taxonID	type	description	language	source
03BB8796F8556E72FF23EC44DD989C54.taxon	type_taxon	Type species: Krohnia lepidota (Krohn, 1845)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8556E72FF23EC44DD989C54.taxon	diagnosis	Diagnosis. Body moderately elongate, transparent. Prostomium extending in front of eyes or greatly reduced. Median antenna present. Eyes large, directed obliquely forward and upward. Margin of proboscis with papillae, without lateral horns. Tentacular cirri according to the formula. Segment 4 and all subsequent ones with fully developed parapodia having foliaceous dorsal and ventral cirri and chaetigerous lobe with one cirriform appendage. Chaetae all simple; mainly capillaries, acicular chaetae at least in anterior parapodia.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8556E7FFF23EDECDD249F7C.taxon	description	(Figs 1 – 4)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8556E7FFF23EDECDD249F7C.taxon	materials_examined	Material examined. One specimen: ZMMU WS 20944 (FA, Et).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8556E7FFF23EDECDD249F7C.taxon	description	Description. Moderately preserved anterior part with 11 chaetigers, 2.5 mm long, 0.7 mm wide at 10 th chaetiger. Body slender, fragile. Prostomium small, not extending in front of eyes. Frontal antennae subequal, large and tapering, inserted close to each other (Fig. 2). Their ventral surface with a few longitudinal rows of small papillae (ventro-lateral rows may be seen from above). Median antenna of about same length, fusiform, its base sandwiched dorsally between eyes (Fig. 2 A). Proboscis not everted in our specimen. Eyes large and directed obliquely forward and upwards (Fig. 2 A). Tentacular cirri arranged as (Fig. 2 B). Dorsal cirri of second pair (D 2) shorter than D 1 and D 3 (D 3> D 1> D 2). D 1 stout, extending considerably beyond outer margin of the eyes. D 3 enlarged; cirrophores extend laterally as wide as eyes’ outer margins. Cirrostyles long, cylindrical, with longitudinal row of large papillae ventrally. Total length of each cirrus exceeds distance between eyes’ outer margins. Ventral cirri smaller than corresponding dorsal ones; V 2 tapering, V 3 foliaceous, can be mistaken for ventral parapodial cirri in dorsal view. All parapodia well-developed (Fig. 3). Dorsal parapodial cirri lost in our specimen; their cirrophores swollen. Chaetigerous lobes with short cirriform appendage and protruding aciculum. Ventral cirri 1.5 – 2 times shorter than parapodial lobes, asymmetrically lanceolate, slightly swollen. Chaetae all simple. First pair of parapodia with one or two stout acicular chaetae (Fig. 3 A). They are straight with the very tip distinctly curved. Next 4 parapodia with 2 – 5 stout acicular chaetae with smoothly curved tips located ventral to aciculum (Fig. 3 B). Two straight acicular chaetae per parapodium in succeeding 4 – 5 chaetigers (Fig. 3 C); single straight and long acicular chaeta per parapodium in rest of segments (Fig. 3 D). Capillaries present in all parapodia. In first pair, one or two chaetae of transitional type present (either short stout capillaries, or slender acicular chaetae). Several short regular capillaries present from second pair of parapodia. Posteriorly, capillaries form broad fan; their size and number increase backwards (Fig. 3 B – D). Segmental glands are vertical cushions located laterally posterior to parapodia from segment 9 (sixth parapodium) (Figs 2, 3 C – D). Margins of ventral parapodial cirri, antennae and tentacular cirri are highly glandular (seen as granular areas which are densely stained by methyl green). Coloration: anterior part transparent with brownish pigmentation confined to parapodial bases, boundaries of segments and mid-ventral line. From first segment with glands, coloration becomes darker, especially around glands. Segmental glands dark brown (almost black). Characteristic pattern is formed by brown dots. Dorsum (Fig. 2 A): two longitudinal rows formed by one or two dots at each parapodial base. Ventrum (Fig. 2 B): two lateral rows formed by dots at parapodial bases (posteriorly obscured by segmental glands. Three (rarely four) dots per segment form ventral middle row. Areas of midline containing dots are slightly swollen. One to three faint (reddish) brown dots along margins of ventral parapodial cirri (Fig. 3).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8556E7FFF23EDECDD249F7C.taxon	discussion	Remarks. Many authors described Krohnia lepidota from different localities; however, their descriptions do not quite match and / or leave some important features uncertain. These differences cannot be readily attributed to geographically distinct populations because contradicting statements are sometimes obtained from the same area. The main features used to distinguish between species of Krohnia are the size of dorsal parapodial cirri, the number of acicular chaetae in anterior chaetigers and the size of the tentacular cirri pair D 3. Of these, only strongly enlarged tentacular cirri D 3 are consistent throughout the descriptions of the species. Along with the characteristic pattern of black / brown dots they were used as the basis for synonymization of some Alciopa, Callizona and Callizonella species with Krohnia lepidota (Apstein 1900; Støp-Bowitz 1948; Dales 1957; Dales & Peter 1972). These notably enlarged tentacular cirri D 3 are found in our specimen, as well. However, a unique feature of its tentacular arrangement is that the smallest pair of dorsal tentacular cirri is D 2, whereas in all available descriptions the size of dorsal cirri simply increases from D 1 to D 3. The presence of acicular chaetae in the anterior segments is not specified in the first description by Krohn (1845); just their presence is noted in descriptions of Callizona cincinnata and Alciopa cirrata by Greeff (1876). Apstein (1900) who studied Krohn’s and Greef’s specimens along with his own material mentions a “ big number ” of acicular chaetae in anterior segments. The same is described by Fernández-Álamo (1983), Ushakov (1972) states that they “ predominate ”. On the contrary, their number is defined as “ some ” by Støp-Bowitz (1948), “ few ” (Day, 1967) or “ several ” (Rozbaczylo et al., 2020), all agreeing in that posteriorly their number reduces to 1 or they disappear. Rice (1987), who regarded the number of acicular chaetae per parapodium in anterior segments as one of the important features was the first to provide certain values: 1 – 3 per parapodium; the same is given in (Støp-Bowitz 1992). A curious case is Callizonella pigmenta which was described as having more numerous acicular chaetae (“ crotchets ”) in parapodia of its rear rather than anterior part (Treadwell 1943). However, Dales (1957) examined Treadwell’s type specimen and came to a conclusion that it is with no doubt conspecific with K. lepidota. Unfortunately, he did not comment on its acicular chaetae arrangement. In our specimen, 2 – 5 acicular chaetae are found in anteriormost chaetigers which is in line with more moderate estimates by Rice (1987) or Day (1967). Length of dorsal parapodial cirri is described as equal to, or even shorter than parapodial lobe in Rice (1987). On the contrary, dorsal parapodial cirri exceeding parapodial lobe (2 – 3 times in anterior region and about 1.5 times posteriorly) are shown by Day (1967: Fig. 7.1, j – k), Ushakov (1972: pl. XXVI, 3) and Rozbaczylo et al. (2020: Fig. 5, E – F). However, some authors draw attention to the fact that dorsal cirri are easily lost and so cannot be described (Støp-Bowitz, 1948; Fernández-Álamo, 1983). This is also true for our specimen. The first description (Krohn 1845) states that frontal antennae are attached close to each other. Frontal antennae arising “ close together ” from small prostomium which does not extend beyond eyes are also described by Day (1967) and can be seen from pictures by Ushakov (1972) and Fernández-Álamo (1983), although this is not specifically mentioned in descriptions. On the contrary, Greeff (1876) describes frontal antennae in Callizona cincinnata as located at both sides of anterior lobe of prostomium extending forward. Rozbaczylo et al. (2020) state that frontal antennae are located closely, but their picture clearly shows antennae attached at a distance from each other to a bluntly conical anterior portion of prostomium extending in front of eyes. Our Red Sea specimen agrees with the first description in having frontal antennae attached close to each other to a small anterior portion of prostomium. Direction of eyes’ axes is described as obliquely forward and upward (Støp-Bowitz 1948), slightly forward (Day 1967; Rozbaczylo et al. 2020), sideways and slightly down (Ushakov 1972), forward (Fernández-Álamo 1983). In the Red Sea specimen, eyes’ axes are directed obliquely forward and upward in accordance with the description by Støp-Bowitz (1948). Thus, compared to any of the cited description, some features of our specimen agree and some do not; but the same happens when comparing different descriptions to each other. The only unique feature of the Red Sea specimen is the arrangement of its tentacular cirri. However, without understanding true intra- and interspecific variability in Krohnia, size ratio of tentacular cirri alone is not enough to justify a new species without support from molecular data, especially with only one specimen at hand. Unfortunately, no sequences from K. lepidota s. l. (or any other species of the genus) are available so far. Thus, we regard K. lepidota as a species complex, until a study including material from different locations and involving molecular methods is carried out.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8556E7FFF23EDECDD249F7C.taxon	distribution	Distribution. The type locality of K. lepidota s. l. is Sicily, the Mediterranean. Later records include: equatorial to temperate Atlantic and Pacific; southwest Indian Ocean; central Red Sea (this study).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8586E7EFF23EE84D8ED99F8.taxon	type_taxon	Type species: Vanadis formosa Claparède, 1870	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8586E7EFF23EE84D8ED99F8.taxon	diagnosis	Diagnosis. Body long and slender. Prostomium not extending in front of eyes. Median antenna present or absent. Proboscis long, often with lateral horns. Three pairs of tentacular cirri arranged as 1 + 1 + 1. First one to seven parapodia (on segments 4 – 10) reduced and may lack chaetigerous lobes and / or chaetae. Dorsal parapodial cirri of one or two anterior segments enlarged in females to form a receptacula seminis. Normal parapodia of succeeding segments have foliaceous dorsal and ventral cirri and long chaetigerous lobes bearing one cirriform appendage. Apart from projecting aciculum, chaetae all compound spinigers. Segmental glands usually pigmented, may be underdeveloped in some segments; in the latter case, alternation of well-developed and underdeveloped glands forms a specific pattern.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8596E7AFF23ED47DC019A88.taxon	description	(Figs 1, 4 – 6)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8596E7AFF23ED47DC019A88.taxon	materials_examined	Material examined. Eighteen specimens: ZMMU WS 20945, ZMMU WS 20946, ZMMU WS 20947, ZMMU WS 20948, ZMMU WS 20949, ZMMU WS 20950, ZMMU WS 20951, ZMMU WS 20953, ZMMU WS 20954, ZMMU WS 20955 (FA, Et); ZMMU WS 20952, ZMMU WS 20956, ZMMU WS 20957, ZMMU WS 20958, ZMMU WS 20959, ZMMU WS 20960, ZMMU WS 20961, ZMMU WS 20962 (FA).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8596E7AFF23ED47DC019A88.taxon	description	Description (based on all our material). Material represented by anterior fragments 2 – 4.5 mm long comprised by 10 – 17 ch and middle fragments of various length. Width at 10 chaetiger 0.3 – 0.4 mm. Body long and very slender with length of parapodia in mid-body noticeably exceeding body width. Prostomium not extending in front of eyes (Fig. 5). Inferior pair of frontal antennae long, digitiform, superior pair stout and 2 – 3 times shorter. Median antenna transformed into more or less distinct ridge between eyes. Eyes large, directed sideways and slightly forward. Proboscis long, slender, with one pair of long pointed lateral horns (Fig. 5 A). No marginal lobes or folds between horns; entire membraneous flanges extend from each horns’ base and converge in center. Three pairs of tentacular cirri arranged as 1 + 1 + 1 (Fig. 5 B). First pair is the longest; cirrostyle is mounted on broad cirrophore attached to lower surface of eye; cirrostyle tip extends to eye’s lens but does not reach eye’s outer margin. Second pair markedly shorter, third one shorter yet. Parapodia of segments 4 to 9 are reduced; parapodial lobe lacking (Figs 5 A – B, 6 A – D). Their dorsal cirri are relatively well developed from first pair. Ventral cirri of first pair of parapodia absent or almost indiscernible (Fig. 6 A). In segments 5 – 8, ventral cirri have appearance of small papillae at bases of dorsal ones (Fig. 6 B – C). In segment 9, ventral cirri almost equal in length to dorsal ones (Fig. 6 D). In females, dorsal cirri of segment 5 are transformed into globular receptacula seminis (Fig. 5 A). Parapodial lobes with chaetae in parapodia from segment 10 onwards (Fig. 6 E – F). They extend only slightly beyond dorsal cirri in segment 10 (Fig. 6 E) but rapidly increase. Their length exceeds body width by segment 14 – 15 (Fig. 6 F) and still continues increasing up to middle body region. Each lobe bears cirriform appendage exceeding tip of protruding aciculum and tuft of fine compound spinigers with obliquely cut shaft-heads and short blades. Subdistal widening only slightly expressed (Fig. 6 F). Dorsal cirri (nearly) reach chaetigerous lobe’s tip in anterior half, extend slightly beyond in remaining part; their shape is ovoid to almost round. Ventral cirri up to two times shorter than dorsal ones, elongated and indistinctly pointed, slightly asymmetrical. Body highly transparent. Majority of specimens completely uncolored with no glands visible (Fig. 5 A). Fewer ones have pale brown coloration of segmental glands usually represented by large central spot accompanied by a few pigment granules (Fig. 5 B).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8596E7AFF23ED47DC019A88.taxon	discussion	Remarks. Dales & Peter (1972) noted that Dales’ earlier figures (Dales 1957) refer to Vanadis fuscapunctata Treadwell, 1906 = Vanadis studeri Apstein, 1893. They did not specify whether it also refers to the text of the paper, but the details of description (primarily brightly colored segmental glands from segment 7 and 5 pairs of reduced parapodia) make us think that it belongs to V. studeri as well. However, this note has been largely overlooked and the material of Dales (1957) has been repeatedly included in synonymies as V. minuta (see e. g. Ushakov 1972; Fernández-Álamo 1983; Rozbaczylo et al. 2020). Vanadis minuta has been previously confused a lot with Vanadis crystallina Greeff, 1876. However, the mentionings of only one pair of receptacula seminis and reduction of the median antenna show that some of such “ V. crystallina ” records and descriptions actually refer to another species; we agree with Støp-Bowitz (1992) that descriptions of Apstein (1900), Fauvel (1923), and Wesenberg-Lund (1939) actually refer to V. minuta. A more confused case is the relation between V. minuta and A. longirhyncha Greeff, 1885. Dales (1957) listed them as synonyms. Although he did not discuss the reasons, this is apparently justified, because Greef (1885) observed only 1 pair of receptacula seminis in his type specimen, followed by 4 segments with reduced parapodia, which conforms to V. minuta. But in their later synopsis, Dales & Peter (1972) listed A. longirhyncha as a synonym of Vanadis formosa Claparède, 1870 without giving any reason for this. However, V. formosa has only 2 pairs of fully reduced parapodia with dorsal cirri of both pairs transformed into receptacula seminis in females. Podial lobe in the third pair is usually just smaller than succeeding ones, although may sometimes need a careful examination to be detected. Thus, maximum 1 pair of partially reduced parapodia are present after 2 pairs of receptacula seminis in this species. Also, V. formosa is characterized by boldly colored segmental organs starting immediately after the beginning of well-developed parapodia, whereas pl. XIV Fig. 37 in Greef’s description shows no pigmentation at all. Thus, we support the earlier Dales’ view. Still, despite the priority of the older name longirhyncha, we consider changing the name of the species undesirable for the following reasons. There are not so many long-accepted names in pelagic polychaetes, and, particularly, in Alciopini. V. minuta is one of the few, whereas A. longirhyncha is apparently one of “ little-known, or even long-forgotten ” names, as defined in the Code. Also, it has been long synonymized with V. formosa and its resurrection as a valid name in replacement of the long-accepted V. minuta could cause confusion. Thus, we consider that this is the occasion when the Principle of Priority is “ to be set aside <…> when its application would be destructive of stability or universality or would cause confusion ” (ICZN 1999). Treadwell (1906) in his description of V. minuta mentions “ segmental organ which is the only trace of color to be seen behind the eyes ”. On the contrary, picture of Alciopa longirhyncha by Greef (1885) shows no pigmentation. Day (1967) described segmental glands in V. minuta as either uncolored or possessing faint brown coloration from segment 12. The same is found in (Orensanz & Ramírez 1973; Fernández-Álamo 1983). It is noteworthy that uncolored specimens are usually recorded from Atlantic, while (weakly) colored ones are more typical of Indo-Pacific. In our material from the Red Sea, both uncolored and colored specimens were present. In the phylogenetic tree, all sequences fell apart in two well supported lineages (Fig. 4) coinciding with these two coloration patterns. No other morphological differences between them could be found. Each lineage itself was quite homogenous. The distance between lineages estimated from nuclear markers (0.4 % for 18 S and 1 % for 28 S) was higher than within-species distances in Vanadis antarctica (McIntosh, 1885) (0.1 % for 18 S and 0.2 % for 28 S), the only Vanadis species for which relatively abundant molecular data from different locations is available. At the same time, it was lower than the between-species distance (0.6 % for 18 S and 2.1 % for 28 S) in the closely related V. antarctica – Vanadis longissima (Levinsen, 1885) species group (Tebble 1960), and considerably lower than the majority of between-species distances in Vanadis (1 to 1.7 %, 1.5 % on average for 18 S; 2.1 – 5.3, 3.4 on average for 28 S; and 18 – 24 % for COI). Interestingly, the distance between the V. minuta lineages estimated from the COI fragments amplified with the PolyLCO – PolyHCO pair (25 %) was even higher than those between all other species in our material (18 to 24 %). However, the doubtfulness of the reliability of the use of sequences obtained from pelagic polychaetes with universal COI primers is argued in the Discussion. Thus, the existence of two (sub) species, one with an Atlantic origin (referring to A. longirhyncha Greef, 1885, tentatively associated with the uncolored lineage), and another one with a Pacific origin (referring to Treadwell’s V. minuta, colored lineage) is likely. However, a study involving additional sequences from Atlantic and Pacific material is needed to confirm their validity and actual distribution.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8596E7AFF23ED47DC019A88.taxon	distribution	Distribution. Type locality of Vanadis minuta Treadwell, 1906 is Hawaii, Pacific. Type locality of Alciopa longirhyncha Greef, 1885 is Gulf of Guinea, Atlantic. Later records of Vanadis minuta s. l. include: tropical and subtropical Pacific, southwest Indian Ocean, tropical and subtropical Atlantic; Central Red Sea (this study).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F85D6E7AFF23EBCADD559C2E.taxon	type_taxon	Type species: Plotohelmis alata Chamberlin, 1919	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F85D6E7AFF23EBCADD559C2E.taxon	diagnosis	Diagnosis. Body small, slender and elongate. Prostomium projecting in front of eyes. Proboscis with marginal papillae but without lateral horns. First three segments bear tentacular cirri according to formula 1 + 1 / 1 + 1 / N or 1 + 1 / 1 + 1 / 1. Segment 4 and all subsequent segments fully developed with foliaceous dorsal and ventral cirri and chaetigerous lobe without cirriform appendage but with projecting aciculum. Chaetae mainly compound spinigers plus few simple acicular chaetae which are more numerous in anterior segments.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F85D6E79FF23ED75DDF49E60.taxon	description	(Figs 1, 4, 7 – 8)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F85D6E79FF23ED75DDF49E60.taxon	materials_examined	Material examined. Seven specimens: ZMMU WS 20963, ZMMU WS 20964, ZMMU WS 20965, ZMMU WS 20966 (FA, Et); ZMMU WS 20967, ZMMU WS 20968, ZMMU WS 20969 (FA).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F85D6E79FF23ED75DDF49E60.taxon	description	Description (based on all our material). Material represented by fragments 2 – 3 mm long comprised by 13 – 20 chaetigers; width at 10 th chaetiger 0.4 – 0.5 mm. Prostomium projects in front of eyes. Frontal antennae tapering, subequal; median antenna hardly discernible, as round papilla (Fig. 7 A). Eyes directed sideways and slightly forward. Proboscis short with 12 marginal papillae. Tentacular cirri arranged as; dorsal ones increasing in size caudally with D 3 being almost equal to body width without parapodia; ventral cirri minute, V 2 <V 3 (Fig. 7 B). All parapodia well-developed, each with oviform and bluntly pointed dorsal cirrus and small ventral cirrus of elongated oviform shape 1.5 – 2 times smaller than dorsal one. Chaetigerous lobe bluntly conical, reaching approximately as far as dorsal cirrus, without cirriform appendage. Parapodia of segments 4 – 12 or 4 – 13 with several strong and stout acicular chaetae with slightly curved tips. In most well-preserved specimen, 3 acicular chaetae are present in parapodia of segments 4 and 5 (Fig. 8 A), 4 – 5 in segments 6 – 11 (Fig. 8 B), and 3 – 4 again in segments 12 and 13 (Fig. 8 C). In some individuals, number of last segments with multiple acicular chaetae lower, as well as their maximum quantity; but see Remarks. Acicular chaetae may be accompanied with single or few short spinigers whose occurrence increases posteriorly. Starting from segment 14 onwards each parapodium bears a tuft of long and fine compound spinigers with obliquely pointed shaft tips and short blades, and only one long and slender acicular chaeta with straight tip (Fig. 8 D). Latter decreases in length caudally. Three or four pairs of genital papillae present in males below parapodia within range of segments 10 – 15 (Fig. 7 B). Segmental glands as vertical ventro-lateral bars behind parapodia. Coloration: body slightly yellowish; small granules of brown pigment scattered across body. Anteriorly, they occur mainly around segmental glands and under parapodia, thus forming two indistinct longitudinal bars on ventral area. Posteriorly they group near segment boundaries. Dorsum pigmented much scarcer than ventrum. Location of pigment granules on dorsum seems irregular. Segmental glands pigmented entirely or contain granules of pigment similar to those scattered across body, but darker and larger, but no branching chromatophores. Pigmentation differs between individuals from rather dense to very poor one including only rare spots confined to segmental glands (especially in females).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F85D6E79FF23ED75DDF49E60.taxon	discussion	Remarks. Acicular chaetae are easily broken in this species. Without cutting off parapodia and preparing a slide, their number and arrangement can be underestimated. But even studying parapodia preparations under a compound microscope allows tracking bases of broken chaetae (Fig. 8 B) only in well preserved specimens. Otherwise, the true number of acicular chaetae in a parapodium can be underestimated even after a careful examination. In our material, multiple acicular chaetae could be seen up to segment 9 – 13 in different individuals, but the ones with fewer acicular chaetae were also the most poorly preserved ones. In the literature, it is usually just mentioned that acicular chaetae predominate in anterior segments and a single one remains in posterior parapodia (Dales 1957; Orensanz & Ramírez 1973; Fernández-Álamo 1983). Day (1967) noted that “ Segments 4 – 10 have three to five acicular setae with curved tips but later ones have only one to two with straight tips ”. Instead of branching chromatophores extending to the ventrum from segmental glands as described by Day (1967) or Orensanz & Ramírez (1973), brown granules of pigment were scattered across the body in all our specimens, although apparently tending to group around segmental glands. Extent of pigmentation varied between individuals. The number and arrangement of genital papillae in males from our material were within the range described by other authors. Specimens included in our phylogenetic analyses embraced as much morphological variability as was possible: genital papillae located within the range of segments from 10 – 12 to 13 – 15; different number and arrangement of acicular chaetae; and different extent of pigmentation. However, obtained sequences were exactly the same (Fig. 5). This confirms high intraspecific variability; exact numbers of segments with genital papillae and multiple acicular chaetae turn out to be of little importance and only general ranges should be taken into account. The difference in pigmentation between our material and literature descriptions remains unclear. Pigmentation patterns in this genus are considered important (Day 1967), so this inconsistency cannot be disregarded. Unfortunately, no other sequences from this species are available for comparison.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F85D6E79FF23ED75DDF49E60.taxon	distribution	Distribution. Type locality: Arrecife, Canary Islands. Succeeding records included mostly subtropical and tropical Atlantic and Mediterranean, which led to a conception that it is a predominantly warm Atlantic form (Støp-Bowitz 1948). Dales (1957) listed (Izuka 1914) as the only existing record outside Atlantic. However, later studies provided records from southwest Indian Ocean (Day 1967), Indian Ocean between Java and Australia (Peter 1974), tropical and subtropical Pacific (Fernández-Álamo 1983) as well. Central Red Sea (this study).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8406E67FF23ED70DB169F09.taxon	type_taxon	Type species: Pelagobia longicirrata Greeff, 1879	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8406E67FF23ED70DB169F09.taxon	diagnosis	Diagnosis. Prostomium with two antennae and two palps; 1 st segment with chaetae and two pairs of tentacular cirri; 2 nd segment without dorsal cirri. Dorsal and ventral cirri digitiform, longer than parapodial lobes; chaetae compound spinigers with smooth shafts.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8406E65FF23EE53DBFB99D4.taxon	description	(Figs 1, 9)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8406E65FF23EE53DBFB99D4.taxon	materials_examined	Material examined. Three specimens: ZMMU WS 20993 (FA, Et), ZMMU WS 20994 (FA), ZMMU WS 20995 (FA, Et).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8406E65FF23EE53DBFB99D4.taxon	description	Description (based on all our material). Body length 5 mm, 12 segments and also range of chaetigers in the material examined. Live worms transparent, with pale-yellow nuchal organs; intestine yellow. Proboscis muscular, with pair of small terminal jaws. Prostomium pentagonal-elongated, with terminal depression, as long as wide. Two pairs of thin filiform appendages (pair of antennae and pair of palps) reach half of prostomium length. Pair of red eyes with lenses, well visible both in live and preserved specimens. Pair of nuchal organs forming distinct conicalrounded lappets on lateral sides of head. Tentacular segment with fascicle of 3 or 4 minute compound chaetae and two pairs of large tentacular cirri of subequal length, reaching 3 rd segment. Acicular structures in tentacular cirri absent. Parapodia of 2 nd segment without dorsal cirri, parapodia of following segments with dorsal and ventral cirri. Dorsal cirri as long as podial lobes; ventral cirri slightly shorter. Each parapodium with tuft of 12 to 16 chaetae and one thick acicula; all chaetae compound spinigers, with long smooth heterogomph shaft and serrated blade. Additional chaetae mentioned by Tebble (1960) and Böggeman (2009) absent. Pygidium short, bifurcated.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8406E65FF23EE53DBFB99D4.taxon	distribution	Distribution. The type locality of P. longicirrata is the Tenerife Bay, Canarian Islands (Greeff 1879). Later records of P. longicirrata include North, South, tropical and subtropical Atlantic, Mediterranean Sea, North Pacific, Indo-Pacific; South Indian Ocean; Central Red Sea (this study). We do not include here the numerous records of P. longicirrata from the Arctic and Antarctic waters because we believe that these may be Pelagobia viguieri Gravier 1911 (Kolbasova et al. 2023).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8406E65FF23EE53DBFB99D4.taxon	discussion	Remarks. Pelagobia longicirrata from the Red Sea conforms well to the P. longicirrata specimens from the Central Atlantic both morphologically and according to the 18 S marker (Fig. 9). They are notably small, and gametes were not found within the body cavity, but the original description of P. longicirrata also gave a body length of only 3 mm and 15 chaetigers (Greeff 1879), while P. longicirrata specimens from the Azores and Ireland were reported to have 14 – 19 segments with a body length of 7 – 8 mm (Støp-Bowitz 1948). Larger specimens from circumpolar regions with 25 chaetigers and the body length of 8 – 12 mm (Ushakov 1972; Isaychev et al. 2013; Kolbasova et al. 2020, 2023) must be P. viguieri (Gravier, 1911).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8426E65FF23E9B4D8CC9BE0.taxon	type_taxon	Type species: Typhloscolex muelleri Busch, 1851	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8426E65FF23E9B4D8CC9BE0.taxon	diagnosis	Diagnosis. Body short, fusiform. Lamellar parapodial cirri cover all the body from lateral sides. Head (prostomium) mushroom-shaped, round, encircled with ventral and dorsal belts of long cilia. Palpodium terminal. Nuchal organs as two rounded dorso-lateral lappets beside dorsal ciliary belt. Head and two first (neck) segments with only one pair of cirri each; following segments (chaetigers) of body trunk with dorsal and ventral cirri. Parapodia uniramous, small, conical, with two short thick chaetae and stout medial protruding aciculum. Pygidium with two flattened caudal cirri.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8426E63FF23EE10DA5D98A4.taxon	description	(Figs 1, 10 C)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8426E63FF23EE10DA5D98A4.taxon	materials_examined	Material examined. Four specimens: ZMMU WS 25592 (Et), ZMMU WS 20977, ZMMU WS 25591, ZMMU WS 25594 (FA).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8426E63FF23EE10DA5D98A4.taxon	description	Description (based on all our specimens). Body 1.2 mm long, 0.2 mm wide without parapodia, 0.4 mm wide with parapodia and cirri with 15 – 23 chaetigers of body trunk. Live worms semitransparent, with orange parapodial cirri, preservedspecimens white. Prostomium mushroom-shaped, round in frontal view, 0.9 body diameter; dorsal and ventral prostomial lobes of similar size, with dorsal and ventral marginal belts of long thick cilia (Fig. 10 C). Apical palpodium consists of cylindrical base and thin distal part (Fig. 10 C). Nuchal lappets rounded, ciliated, attached to base of dorsal prostomial lobe (Fig. 10 C). Extended proboscis not observed. Three anterior cirri situated in angle, 1 st (cephalic) and 3 rd (neck) situated one above another, whereas 2 nd (neck) one displaced ventrally. First (cephalic) cirrus cordiform (with anterior cleft or notch) or butterfly-shaped (with anterior notch and posterior cleft), 2 nd and 3 rd (neck) cirri bean-shaped or oval. All following segments (chaetigers) with dorsal and ventral podial cirri (Fig. 10 C). Dorsal cirri cordiform-rounded in mid-region, oval in posterior; the largest ones in the middle of the body. Ventral cirri of same shape, usually slightly smaller, than dorsal. Parapodia start from 3 rd chaetiger, small, conical, uniramous, each with two simple recurved capillary chaetae, and one thick aciculum penetrating epidermis. Caudal cirri oval (Fig. 10 C).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8426E63FF23EE10DA5D98A4.taxon	distribution	Distribution. Cosmopolitan. Red Sea (this study).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8426E63FF23EE10DA5D98A4.taxon	discussion	Remarks. Our T. cf. muelleri specimens do not have reliable morphological differences from T. mullerii specimens from the Atlantic. However, 18 S and 28 S LSU markers show significant difference; therefore, we use a “ cf. ” qualifier, as recommended in Sigovini et al. (2016).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8446E63FF23ED87D8F19FF6.taxon	type_taxon	Type species: Sagitella kowalewskii Wagner, 1872	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8446E63FF23ED87D8F19FF6.taxon	diagnosis	Diagnosis (emended). Body short, fusiform. Prostomium with terminal palpodium, ciliary belts absent. Caruncle absent or poorly pronounced. Nuchal organs not encompassing the caruncle, as two semicircular ridges on posterior part of prostomium. First three segments lack parapodia and bear three pairs of lamellar cirri enfolding head. Each chaetiger of body trunk with large lamellar dorsal and ventral cirrus and poorly marked podial lobe. Parapodia uniramous, acicular, with two simple stout chaetae and one thick protruding aciculum. Pygidium with two flattened appendages.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8446E63FF23E9FCD81D9C7D.taxon	description	(Figs 1, 10 D, 11)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8446E63FF23E9FCD81D9C7D.taxon	materials_examined	Material examined. Two specimens: ZMMU WS 20978, (Et), ZMMU WS 20979 (FA).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8446E63FF23E9FCD81D9C7D.taxon	description	Description (based on all our material). Body 1 – 1.5 mm long, 0.14 – 0.2 mm wide without parapodia, 0.3 – 0.4 mm wide with parapodia and cirri, robust and stocky, with 9 – 12 chaetigers. Live worm is orange-brown, translucent, proboscis opaque red, prominently visible inside the head, even when inverted. Preserved specimen white, without pigment patterns. Prostomium mushroom-shaped, round in frontal view, like in T. muelleri and T. phyllodes, dorsal and ventral prostomial lobes of similar size, with dorsal and ventral marginal belts of cilia (Fig. 10 D). Apical palpodium consists of cylindrical base and thin distal part (Fig. 10 D). Nuchal lappets rounded, ciliated, attached to base of dorsal prostomial lobe (Fig. 10 D). Extended proboscis small, conical. First (cephalic) cirrus butterfly-shaped (with anterior and posterior notches or with anterior notch and posterior cleft), 2 nd pair bean-shaped or oval, 3 rd pair spoon-like (Fig. 10 D). Dorsal cirri of body chaetigers rounded cordiform in mid-region, oval in anterior and posterior, 0.5 – 0.8 diameters of chaetiger in length; the largest ones in the second third of the body. Ventral cirri slightly smaller than dorsal ones, oval (Fig. 10 D). Parapodia from 3 rd – 4 th chaetigers, small, conical, uniramous, each with two simple recurved capillary chaetae and one thick aciculum penetrating through epidermis. Caudal cirri oval, elongated, slightly tapering (Fig. 10 D).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8446E63FF23E9FCD81D9C7D.taxon	distribution	Distribution. Type locality: North, tropical and subtropical Atlantic (Friedrich 1950); Central Red Sea (this study).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8446E63FF23E9FCD81D9C7D.taxon	discussion	Remarks. Typhloscolex robustus differs from other Typhloscolex species by 1) spoon-like 3 rd pair of cephalic cirri, 2) very conspicuous red proboscis inside the head, and 3) intensive orange-brown coloration. Specimens from the Red Sea are similar to T. robustus from the Central Atlantic and agree with Friedrich’s original description (Friedrich 1954).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8446E60FF23EF0BDC1E9880.taxon	description	(Figs 1, 11, 12 A – B)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8446E60FF23EF0BDC1E9880.taxon	materials_examined	Material examined. Three specimens: ZMMU WS 20980 (FA, Et), ZMMU WS 20981 (FA), ZMMU WS 20982 (Et).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8446E60FF23EF0BDC1E9880.taxon	description	Description (based on all our material). Body 15.8 – 20 mm long, 0.5 – 0.6 mm wide without parapodia, 0.6 – 1 mm wide with parapodia and cirri, graceful and slender, with 28 – 30 chaetigers of body trunk. Live worms transparent, with intersegmental dissepiments well visible through body wall; ethanol- and formalin-fixed specimens semitransparent white. Prostomium conical, pointed, with small terminal palpodium and with dorsal thickening above retort organ (Fig. 12 A). Nuchal organs as two low semi-circular ridges on dorsal side of prostomium (Fig. 12 A). Extended proboscis not observed. Three anteriormost pairs of cirri oval, covering head region. First pair attached near base of palpodium, second pair attached at level of nuchal organs (Fig. 12 A). All chaetigers with dorsal and ventral podial cirri. Dorsal cirri rounded with pointed dorsal edge in first third of body, rectangular with pointed dorsal edge in middle of body; three-four last ones narrow, lanceolate. Ventral cirri of same shape as dorsal ones, but slightly smaller. Parapodia from 3 rd – 4 th chaetiger, small, conical, uniramous, each with two simple recurved capillary chaetae, and one thick aciculum penetrating through epidermis. Caudal cirri broad, irregularly triangular; supporting hyaline rib closer to outer side of cirrus (Fig. 12 B).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8446E60FF23EF0BDC1E9880.taxon	distribution	Distribution. Cosmopolitan. Type locality: Bay of Naples (Wagner 1872). Central Red Sea (this study).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8476E60FF23E9D5DBFD9FBA.taxon	description	(Figs 1, 11, 12 C – F)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8476E60FF23E9D5DBFD9FBA.taxon	materials_examined	Material examined. Seven specimens: ZMMU WS 20983, ZMMU WS 20984, ZMMU WS 20985, ZMMU WS 20986, ZMMU WS 20987 (Et); ZMMU WS 20988 (FA), ZMMU WS 20989 (FA, Et).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8476E60FF23E9D5DBFD9FBA.taxon	description	Description (based on all our material). Body 2.5 – 3.2 mm long, 0.4 – 0.6 mm wide without parapodia, 0.5 – 0.7 mm wide with parapodia and cirri, with 21 – 23 chaetigers of body trunk. Depending on amount of food swallowed, body may be slender or thick and fusiform (Fig. 12 C – E). Live worms semi-transparent; ethanol- and formalin-fixed specimens semitransparent white. Prostomium conical, pointed, with small terminal palpodium. Nuchal organs as two low semicircular ridges on dorsal side of prostomium (Fig. 12 C). Caruncle is poorly pronounced, semiglobular and not encompassed by the nuchal organs (Fig. 12 C). Extended proboscis short, funnel-like (Fig. 12 F). Three anteriormost pairs of cirri oval, covering head region. First pair attached at level of nuchal organs, second pair attached at level of head and neck border (Fig. 12 C). All chaetigers with dorsal and ventral podial cirri. Podial cirri oval and relatively small, they do not cover lateral sides of chaetigers (Figs 12 E – F). Parapodia from 3 rd – 4 th chaetiger, small, conical, uniramous, each with two simple recurved capillary chaetae, and one thick aciculum penetrating through epidermis. Caudal cirri very large, larger than all podial cirri, oval with opaque middle rib (Fig. 12 D).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8476E60FF23E9D5DBFD9FBA.taxon	distribution	Distribution. Type locality: North Atlantic, Gulfstream, 39.50 ° N, 49.70 ° W (Støp-Bowitz 1948). Later records of Sagitella dubia comb. nov. include: tropical and subtropical Atlantic, Indo-Pacific; Central Red Sea (this study).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8476E60FF23E9D5DBFD9FBA.taxon	discussion	Remarks. This species was described by Støp-Bowitz (1948) as Travisiopsis dubia. However, the author himself had doubts about referring this species to the genus Travisiopsis which is reflected in the species name “ dubia ” and is commented on in the original paper: “ In spite of the shape of body resembling more a Sagitella I refer this species to the genus Travisiopsis because of the possession of a caruncle, and the size of the caudal cirri. ” (Støp-Bowitz 1948). Nevertheless, both 18 S and 28 S markers cluster this worm together with S. kowalewskii. Therefore, we emended the diagnosis of Sagitella by deleting the absence of caruncle. Sagitella dubia comb. nov. differs from S. kowalewskii by the location of cephalic cirri. While S. kowalewskii has the 1 st pair of cephalic cirri almost at the base of the palpodium, and the 2 nd pair at the level of the nuchal organs, in Sagitella dubia comb. nov., the 1 st pair is attached at the level of the nuchal organs, and the 2 nd is attached on the neck (Fig. 12 A and C). This morphological characteristic is very convenient, since the places where cirri used to be attached are visible even in damaged specimens.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8476E60FF23EF00DDA19ED8.taxon	materials_examined	Type species: Tomopteris oniscoformis Eschscholtz, 1825	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8476E60FF23EF00DDA19ED8.taxon	diagnosis	Diagnosis. Prostomium with two horns, fused with peristomium and first segment. Pharynx unarmed. First segment is reduced in adults, 2 nd segment with pair of very long cirri supported by long acicula. Parapodia biramous with elongated trunk, short tapering rami, and different types of parapodial glands. Chaetae absent.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8496E6EFF23E8B1DAFD9D4F.taxon	description	(Figs 1, 13, 14)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8496E6EFF23E8B1DAFD9D4F.taxon	materials_examined	Material examined. One specimen: ZMMU WS 20990 (FA, Et).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8496E6EFF23E8B1DAFD9D4F.taxon	description	Description. Body oval, elongate, 10 mm long 1 mm wide without parapodia, 4 mm wide with parapodia Tail absent, posterior ends with short cylindrical pygidium, maximum width with parapodia 3 mm, maximum width of body trunk 1 mm (Fig. 13 A). Live worms transparent, white in preservation, eyes red. Brain transversely oval (Fig. 13 B). Body with 12 pairs of parapodia, increasing in size up to 3 rd pair and then decreasing toward posterior end (Fig. 13 A). Prostomium with frontal cleft, prostomial horns slightly curved backward. Ciliated epaulettes long, narrow, extending to posterior margin of brain. Anterior cirri as long as the frontal horns (Fig. 13 B). Secondary cirri (streamers) approximately 0.85 of body length (Fig. 13 A). Dorsal and ventral rami of parapodia of equal length. Pinnules oval, pinnal membranes do not adnate to parapodial trunk (Fig. 13 C and D). Chromophile glands mammillary, loose and incompact (Fig. 13 C, D). They are present from 1 st pair of parapodia, but poorly visible in first two pairs (seen as 3 – 4 tubes with a common opening). In 3 rd pair of parapodia these tubes become arranged into well-visible chromophile glands, from 4 th pair chromophile glands occupy almost all space between ramus and inferior margin of pinnule (Fig. 13 D). Hyaline glands absent. Rosettes of two types. Large yellow spherical rosettes within trunks of 1 st and 2 nd parapodial pairs, near bases of dorsal rami (Fig. 13 A – C). Smaller yellow rosettes in dorsal and ventral pinnules of all parapodia against inner side of rami (Fig. 13 D). Gonads not observed.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8496E6EFF23E8B1DAFD9D4F.taxon	distribution	Distribution. Type locality: Rolas Canal, Sao Thome (Greeff 1885). Other localities: tropical and subtropical Atlantic, Indo-Pacific, Central Red Sea (this study).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F8496E6EFF23E8B1DAFD9D4F.taxon	discussion	Remarks. According to 18 S and 28 S markers, T. rolasi from the Red Sea is close to T. helgolandica (Fig. 14); nevertheless, these two species are distinctly different morphologically.	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F84B6E6BFF23E8B1DC0B9AE4.taxon	description	(Figs 1, 14 – 15)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F84B6E6BFF23E8B1DC0B9AE4.taxon	materials_examined	Material examined. Four specimens: ZMMU WS 20991, ZMMU WS 20992 (FA, Et), ZMMU WS 22577, ZMMU WS 22578 (Et)	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F84B6E6BFF23E8B1DC0B9AE4.taxon	description	Description (based on all our material). Body oval, elongate, 5 – 10 mm long, 0.6 – 1 mm wide without parapodia, 2.5 – 4 mm wide with parapodia. Tail absent, posterior ends with short cylindrical pygidium, maximum width with parapodia 2.6 mm, maximum width of body trunk 0.9 mm (Fig. 15 A). Live worms transparent, white in preservation. Eyes red. Brain transversely oval (Fig. 15 B). Body with 14 pairs of parapodia increasing in size to 3 rd pair; 4 – 6 pairs longest; from 7 th pair, parapodia decrease toward posterior end. Prostomium with frontal cleft, prostomial horns slightly curved backward. Ciliated epaulettes triangular, extending to posterior margin of brain. Anterior cirri absent (Fig. 15 B). Secondary cirri (streamers) 1 – 1.2 of body length. Dorsal and ventral parapodial rami of equal length (Fig. 15 C – E). Pinnules oval, pinnal membranes do not adnate to parapodial trunk, membrane in dorsal ramus slightly lower than in ventral ramus. Hyaline glands apical, from 1 st pair of parapodia in ventral pinnules (Fig. 15 C – E). Chromophile glands from 3 rd parapodial pair, in 3 rd pair of parapodia they incompact and poorly visible, from 4 th parapodial pair chromopile glands with 8 – 10 tubes, compact and large; base of ventral ramus terminates at proximal end of chromophile gland and not bordered by pinnule (Fig. 15 C – E). Small yellow rosettes present from 1 st pair of parapodia, they are located in ventral pinnule between chromophile and hyaline glands (Fig. 15 C – E). Gonads in dorsal rami (Fig. 15 E).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F84B6E6BFF23E8B1DC0B9AE4.taxon	distribution	Distribution. Type locality: Labrador, Guinea, South Equatorial currents (Apstein 1900). Later records for T. planctonis include: Atlantic Ocean from Greenland to Antarctica, Mediterranean, Pacific; Central Red Sea (this study).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
03BB8796F84B6E6BFF23E8B1DC0B9AE4.taxon	discussion	Remarks. Both morphologically and according to 18 S and 28 S markers, T. planktonis from the Red Sea is similar to T. planktonis from the Weddell Sea. Applicability of the COI marker obtained with universal primers in holopelagic annelid families General topology of the tree inferred from nuclear 18 S and 28 S including all considered families is presented in Fig. 16 A. It conforms to contemporary conception of relationships between holopelagic annelid families. However, including COI sequences in the analysis introduces some changes in the topology above genus level, although it does not affect the species-level results. Thus, in 18 S + 28 S + COI concatenated tree within the family Typhloscolecidae, the genus Typhloscolex becomes non-monophyletic with one lineage merged inside Travisiopsis (Fig. 16 B). Tomopteridae are grouped with Glyceridae in the 28 S + 18 S tree (Fig. 16 A). Conversely, when the COI is added to the analysis, the Tomopteridae clade becomes a sister group to Typhloscolecidae (Fig. 16 B). Nothing changes only in Alciopini, which are nested within Phyllodocidae regardless of which set of markers was used (Fig. 16).	en	KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L., CARVALHO, S. (2025): Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast. Zootaxa 5632 (1): 1-41, DOI: 10.11646/zootaxa.5632.1.1, URL: https://doi.org/10.11646/zootaxa.5632.1.1
