Ophelina grandis ( Pillai, 1961 )

Parapar, Julio, Al-Kandari, Manal, Barroso, María & Moreira, Juan, 2023, The genus Ophelina Örsted, 1843 (Annelida: Opheliidae) in the coast of Kuwait (northern Indian Ocean), with the description of a new species, European Journal of Taxonomy 870 (1), pp. 1-29 : 12-21

publication ID	https://doi.org/ 10.5852/ejt.2023.870.2113
publication LSID	lsid:zoobank.org:pub:21226C21-DFF4-4EFD-A715-48EFF16C5F55
DOI	https://doi.org/10.5281/zenodo.7908239
persistent identifier	https://treatment.plazi.org/id/CF4F1F70-B832-FFCE-B379-196F14F9F9A3
treatment provided by	Felipe
scientific name	Ophelina grandis ( Pillai, 1961 )
status

Treatment

Ophelina grandis ( Pillai, 1961) View in CoL

Figs 6–11 View Fig View Fig View Fig View Fig View Fig View Fig , 12 A–B, D–E View Fig , 13 View Fig

Ammotrypane grandis Pillai, 1961: 25-27 View in CoL , fig. 9a-c.

Ammotrypane grandis Pillai View in CoL – Hartman 1959: 428. — Gallardo 1968: pl. 52 fig. 5: 112. — Hartman 1974: 627. — Phasuk 1992: 85.

Ophelina grandis (Pillai) View in CoL – Eibye-Jacobsen 2002: 69. — Neave & Glasby 2013: 336, tab. 4.

Diagnosis

Parapodial prechaetal lobe elongated and triangular throughout; ventral lobe low and lingulate. Anal tube long, delicate, spoon-shaped, annulated; posterior and ventral margins free, tube opening well-defined, provided with about 15 pairs of marginal papillae; a pair of basal papillae and unpaired anal cirrus attached basally on ventral margin and projecting inside tube.

Material examined

Holotype

SRI LANKA • Tambalagam Lake ; NHM 1960.3.13.17 .

Paratypes

SRI LANKA • 1 spec.; same collection data as for holotype; NHM 1960.3.13.18 • 1 spec.; same collection data as for holotype; NHM 1960.3.13.19 • 1 spec.; same collection data as for holotype; NHM 1960.3.13.20 • 1 spec.; same collection data as for holotype; NHM 1960.3.13.21 .

Additional material

KUWAIT • 1 spec.; Failaka Island ; 29.39383° N, 48.39930° E; 24 Dec. 2014; sample P12610 code FI3; mid intertidal; fine sand; MNCN 16.01/17005 GoogleMaps • 1 spec. (mounted for SEM); same collection data as for preceding; MNCN 16.01/17006 GoogleMaps • 1 spec.; Failaka Island ; 29.65636° N, 48.66550° E; 24 Dec. 2014; sample P12611 code FI3; mid intertidal; fine sand; MNCN 16.01/17007 GoogleMaps • 1 spec.; Sulaibikhat Bay ; 29.352483° N, 47.887467° E; 13 Oct. 2019; sample M1828 code KB5; subtidal; mud; MNCN 16.01/17009 GoogleMaps • 1 spec.; same collection data as for preceding; sample M1835 code KB5; MNCN 16.01/17010 GoogleMaps .

Description

MEASUREMENTS. Complete specimens ranging from 15–31 mm in length and 1.0–2.0 mm in width for 61–64 chaetigers.

BODY. Body slender, tubular, progressively tapering in last 5–6 chaetigers ( Figs 8A, C View Fig , 11A–B View Fig ); lateral and ventral grooves extending from anterior to posterior body end ( Fig. 11A, E–F View Fig ).

PROSTOMIUM AND PERISTOMIUM. Prostomium pointed; terminal palpode on distal end ( Figs 7A View Fig , 8A–B View Fig , 11E View Fig ). Prostomial eyes not seen. Nuchal organs large, as deep oval lateral depressions ( Figs 7A View Fig , 8B View Fig , 9A, C View Fig ). Buccal tentacles of one type, ca 150 mm long, apparently arranged in two rows of three each ( Fig. 9A–B View Fig ).

PARAPODIA AND CHAETAE. Parapodia biramous; each parapodium provided with a prechaetal lobe and a ventral lobe; dorsal cirrus not present. Prechaetal lobe elongated, triangular throughout; ventral lobe low, lingulate ( Figs 7B–D View Fig , 9D–F View Fig , 10A–D View Fig ). CH 3 prechaetal lobe 0.2 times as long as branchiae; from following chaetigers 0.1 times as long as branchiae. Chaetae all simple, long capillaries, arranged in two rows ( Fig. 10B View Fig ); those of anterior parapodia oriented laterally or posterolaterally. Notochaetae generally longer than neurochaetae; in anterior and posterior parapodia as long as branchiae and 0.5 times as long as branchiae in mid-body.

BRANCHIAE. Present from CH 2 ( Figs 7A View Fig , 9A View Fig ) to last chaetiger ( Fig. 7E–G View Fig ). Anterior chaetigers branchiae as long as body width, about 0.8 times as long in mid-body and 1.2 times as long in posterior chaetigers.

ANAL TUBE. Anal tube spoon-shaped ( Figs 7E, G View Fig , 11C–D, F View Fig ) slightly compressed laterally at most, three times longer than wide, as long as 10 posterior-most chaetigers; with about 40 annulations ( Figs 7E View Fig , 8C View Fig , 11C–D View Fig ); posterior and ventral margins free, not fused, tube opening well defined, margins provided with about 15 pairs of deciduous marginal papillae, highly variable in length; the longest about 0.5 times as long as tube width ( Figs 7E–G View Fig , 8C View Fig , 11C–D View Fig ); a pair of basal papillae about 0.25 as long as anal tube and 0.5 times as long as last branchiae ( Figs 7E–F View Fig , 8C View Fig ); unpaired anal cirrus attached basally on ventral margin and projecting inside, about 0.66 times as long as tube ( Figs 7E, G View Fig , 8C View Fig , 11B View Fig ).

PIGMENTATION. Light brown in preserved specimens ( Figs 8 View Fig , 11 View Fig ).

Remarks

Ophelina grandis ( Pillai, 1961) was originally described from Tambalagam Bay ( Sri Lanka) ( Fig. 13 View Fig ). Pillai (1961) characterises this species by the following: (1) body length ranges from 18.0 to 34.5 mm for 62–66 pairs of parapodia; (2) proboscis funnel-shaped with 7 short oral cirri; (3) notochaetae of first 2–3 chaetigers much larger than those of following and directed forward ( Fig. 12A View Fig ); (4) long cirriform branchiae from CH 2 to the last segment ( Fig. 12B View Fig ); (5) small reddish-brown pigment spot (“not eyes”, sensu Pillai 1961) present in each branchia (“not in all specimens”, sensu Pillai 1961); (6) anal tube spoon-shaped with rim provided with short and slender papillae, the posterior ones being shorter ( Fig. 12B View Fig ); (7) two quite short and slender paired basal papillae and unpaired anal cirrus (“missing in some specimens, very short in few and long in the others”, sensu Pillai 1961) ( Fig. 12B View Fig ). These diagnostic characters were present in the specimens we examined from the Arabian Gulf, apart from (3) (= long anterior notochaetae). In fact, this feature could not be confirmed in the photographs of the type of material provided by the NHM ( Fig. 11 View Fig ).

Rullier (1965) describes Ophelina gigantea ( Rullier, 1965; as Ammotrypane ) from eastern Australia ( Fig. 13 View Fig ), that resembles O. grandis in the number of chaetigers (65–68), parapodia shape (“sétigères suivants portent une longue branchie cirriforme et un court cirre ventral”; Rullier 1965: 190), branchiae of same length present to the last chaetiger (“branchies se rencontrent jusqu’à pygidium et elles sont pratiquement la même taille”; Rullier 1965: 190) and anal tube shape (“...en cuiller, ouvert ventralement, formé d’une membrane translucide veinée d’une quarantaine de côtes transversales et bordée d’une centaine de très petites papilles cylindriques. Il existe deux petites papilles anales continuant les bords du tube anal et un cirre impair beaucoup plis long, logé dans la cavité du tube anal”; Rullier 1965: 191) ( Fig. 12C View Fig ). However, O. gigantea is much longer (62–64 mm vs 15–31 mm in O. grandis ) and marginal papillae are proportionally smaller when compared to anal tube width. Rullier (1965) does not provide a comparison with type specimens of O. grandis and compares O. gigantea instead with O. sibogae ( Indonesia) , O. kampeni ( Malaysia) , O. buitendyki ( Horst, 1919) (Java) and O. norvegica Støp-Bowitz, 1945 ( Norway) . These four species are shorter in length, bear fewer chaetigers and anal tube shape is different (“De plus, la forme de la tête et surtout du tube anal distinguent ces espèces de celles que nous décrivons”; Rullier 1965: 191).

Gallardo (1968) later reported O. grandis from Nha Trang Bay ( Vietnam) ( Fig. 13 View Fig ), highlighting the similarities with O. gigantea , but proposing two distinctive characters: in O. gigantea the anal tube is longer (“pygidial organ” sensu Gallardo 1968), and marginal papillae are shorter (cf. Fig. 12B View Fig vs Fig. 12C View Fig ). We agree with Gallardo (1968) but also noticed that the pair of basal papillae and posterior marginal ventral papillae are of different sizes in O. grandis while in O. gigantea they are mostly similar to each other and smaller, in turn, than those of O. grandis . Furthermore, the anal tube looks truncated posteriorly in O. grandis but more pointed distally instead in O. gigantea . Gallardo (1968) also proposed a novel taxonomic character not previously considered for the genus (and not considered afterwards so far): number, shape, and arrangement of buccal tentacles (cf. Gallardo 1968: pl. lii–liii). Examination of tentacles with SEM in a specimen from Kuwait ( Fig. 9A–B View Fig ) confirms previous observations by Pillai (1961) and Gallardo (1968) ( Fig. 12D View Fig ). These tentacles are similar to those of O. dubia ( Caullery, 1944) (cf. Gallardo 1968: pl. lii fig. 2) and quite different from those of O. longicaudata and O. leptocirris ( Gallardo 1968: pl. lii figs 3–4); therefore, examination and description of tentacles in future work might serve indeed to differentiate species ( Gallardo 1968).

More recently, Eibye-Jacobsen (2002) also reported O. grandis from the Andaman Sea, including specimens previously studied by Phasuk (1992). This material differs from the original description regarding the size and arrangement of chaetae of CH 1–2 and by having fewer marginal papillae in the anal tube ( Fig. 12E View Fig ); the latter might be due, however, to manipulation of specimens ( Eibye-Jacobsen 2002).

Ophelina sibogae was originally described from depths of 9 m, which agrees with our findings in Kuwait. This species is similar to O. grandis in body length (15–30 mm), number of chaetigers (55–65) and anal tube shape (“forme de cuiller à concavite ventrale, pourvue d’une fine annulation transversale … Sur les bords latéraux libres, sont insérées un certain nombre de papilles cirriformes … A son interieur, sur la ligne médiane, on trouve un cierre impar”; Caullery 1944: 41). However, both species differ in the following ( Fig. 12F View Fig ): (1) marginal papillae are of the same length in O. sibogae ; (2) the unpaired anal cirrus is small and about 0.8 times as long as the tube (cf. Neave & Glasby 2013); (3) branchiae are shorter on last chaetigers. In addition, the pair of basal papillae are apparently not present, but Neave & Glasby (2013) mentioned such a feature probably after the illustration provided by Caullery (1944: fig. 31). However, a revision of the type specimens of O. sibogae is needed to assess whether O. grandis is a different species.

Other two species described from the Indian Ocean are similar to O. grandis : O. kampeni and O. langii ( Kükenthal, 1887) ( Fig. 12G–H View Fig ). Ophelina kampeni also has an anal tube that is spoon-shaped and bears short marginal papillae along its free margins; the tube is also provided with a pair of basal papillae and unpaired anal cirrus within ( Horst 1919: fig. 1; Fig. 12G View Fig ); this species lacks instead parapodial ventral cirri (“prechaetal lobe” in Horst 1919) and bears shorter branchiae not reaching median dorsal body line. On the contrary, O. grandis bears a well-developed prechaetal lobe in parapodia ( Figs 9D–F View Fig , 10A, C–D View Fig ), and anterior and posterior branchiae are much longer, surpassing dorsal body margin ( Fig. 8A–C View Fig ). Besides, the anal tube of O. kampeni is provided with a pair of basal papillae and marginal papillae that are of different lengths to those of O. grandis ( Figs 7E–G View Fig , 8C View Fig , 11B–D View Fig vs Fig. 12G View Fig ), i.e., the pair of basal papillae are about 0.2 times as long as last branchiae in O. kampeni ( Fig. 12G View Fig ) and 0.5 times in O. grandis ( Fig. 12B View Fig ); marginal papillae of O. kampeni are of the same length and 0.5 times as long as the pair of basal papillae and about 0.05 times as long as anal tube height. In contrast, O. grandis posterior and ventral marginal papillae differ in length; the latter is also as long as the pair of basal papillae and about 0.2 times as long as the anal tube height. Regarding O. langii , several features are shared with O. grandis following Kükenthal (1887): (1) length (23.0 mm), width (1.3 mm), and a number of chaetigers (50) are similar; (2) branchiae are long and conspicuously pointed and quite crowded in last chaetigers; (3) anal tube is tubular in shape, translucent, opened ventrally and provided with>20 annulations ( Kükenthal 1887: pl. xxi fig. 5; Fig. 12H View Fig ). However, the anal tube of O. langii has free ventral and posterior margins that lack marginal papillae, a pair of basal papillae and the unpaired anal cirrus ( Horst 1919).

Ophelina longicaudata (Andaman Sea) and O. longicirrata Hartmann-Schröder & Parker, 1995 (South Australia) ( Fig. 13 View Fig ) also bear an anal tube similar to that of O. grandis . However, O. longicaudata has the ventral margins totally fused, and the unpaired anal cirrus is much longer as explained above ( Caullery 1944: fig. 35). Regarding O. longicirrata , the anal tube is provided only with marginal papillae on the posterior margin ( Hartmann-Schröder & Parker 1995: fig. 11), that is, in turn, larger than in O. grandis , also lacking the pair of basal papillae and unpaired anal cirrus; Hartmann-Schröder & Parker (1995) refer, however, to a “ventral cushion that may be base of a lost unpaired cirrus” and also state that O. fauveli ( Caullery 1944: fig. 35) is close to O. longicirrata but bears a shorter anal tube (see also Remarks for O. arabica sp. nov.).

Ophelina cyprophilia Neave & Glasby, 2013 (North Australia) ( Fig. 13 View Fig ) is distinguished from O. grandis because of the shorter branchiae, the shape of the anal tube, and having fewer and smaller paired marginal papillae ( Neave & Glasby 2013). We also point to two further differences: (1) the anal tube profile is not truncated in O. cyprophilia ; (2) the pair of basal papillae (as “paired anal cirri” in Neave & Glasby 2013) are shorter in O. cyprophilia (0.3 times as long as anal tube) than in O. grandis (up to 0.5 times as long as tube) ( Neave & Glasby 2013: fig. 6a–b).

Two European species were reported in the Arabian Gulf (namely O. cylindricaudata and O. acuminata ), and their anal tube resembles that of O. grandis . In O. cylindricaudata , the anal tube is tubular in shape and about as long as the last six chaetigers. However, the ventral margin is fused and lacks marginal papillae, as in O. grandis ( Kongsrud et al. 2011: fig. 3c). Ophelina acuminata bears such papillae instead but the anal tube is spoon-shaped, and the pair of basal papillae are thicker than in O. grandis (StopBowitz 1945: fig. 3). Therefore, it is likely that the previous records of these two species in the Arabian Gulf may correspond to O. grandis or other still not described species.