Nanaloricus valdemari, Neves & Kristensen & Møbjerg, 2021

Neves, Ricardo Cardoso, Kristensen, Reinhardt Møbjerg & Møbjerg, Nadja, 2021, New records on the rich loriciferan fauna of Trezen ar Skoden (Roscoff, France): Description of two new species of Nanaloricus and the new genus Scutiloricus, PLoS ONE (e 0250403) 16 (5), pp. 1-42 : 4-15

publication ID	https://doi.org/ 10.1371/journal.pone.0250403
DOI	https://doi.org/10.5281/zenodo.12630837
persistent identifier	https://treatment.plazi.org/id/0396B203-6914-517B-FD9F-FC62C3F8FA67
treatment provided by	Felipe
scientific name	Nanaloricus valdemari
status	sp. nov.

Treatment

Nanaloricus valdemari View in CoL sp. nov.

( Figs 1–7 View Fig 1 View Fig 2 View Fig 3 View Fig 4 View Fig 5 View Fig 6 View Fig 7 ).

urn:lsid:zoobank.org:act:A0E2CDB1-6F62-4F86-82DF-43F2A06ED519

Synonymy. Nanaloricus sp. sensu [ 26]; Nanaloricus n. sp. sensu [ 27].

Material examined. Holotype ( Fig 1 View Fig 1 ). Adult male collected on 7 February 2013 at the type locality at ca. 45 m water depth, mounted in glycerin on a glass slide, and deposited at the Natural History Museum of Denmark under accession number NHMD-678720.

Allotypic paratype ( Fig 4 View Fig 4 ). Adult female collected on 15 May 2013 at the type locality at ca. 50 m water depth, mounted in glycerol on a glass slide, and deposited at the Natural History Museum of Denmark under accession number NHMD-678736 .

Paratypes. 27 adults (5 males, 21 females, 1 of unkown gender) and 6 tentatively assigned postlarvae collected at the type locality between 12 July 1985 and 15 May 2013 at 43–55 m water depths. The 33 paratypic specimens are mounted in glycerin, Vectashield or Fluoromount-G on glass slides, and deposited at the Natural History Museum of Denmark under the access numbers NHMD-677708 to NHMD-677713, NHMD-677716 to NHMD-677719, NHMD-677721 to NHMD-677734 and NHMD-677737 to NHMD-677744. The specimen registered with access number NHMD-677725 is shown in Fig 5 View Fig 5 . In addition , three adult males collected at the type locality on 12 July 1985 at ca. 55 m water depth, and mounted on SEM stubs (NHMD-866002 to NHMD-866004) were analyzed for comparative purposes ( Fig 7 View Fig 7 ) .

Additional reference material ( Fig 6 View Fig 6 ). In addition to the fixed material examined, 11 non-type specimens (one tentatively assigned postlarva, four males and six females), collected at the type locality in April 2019 and August 2020, were observed and photographed alive.

Habitat and distribution. Marine sediments composed of clean shell gravel at type locality.

Type locality. Trezen ar Skoden, Roscoff, France, (48˚45’55”N, 04˚06’45”E).

Etymology. The species is named after Valdemar MØbjerg Boslev Kristensen, who is grandson and nephew to the middle author and last author, respectively.

The following description will solely focus on adult specimens, as postlarvae have only been tentatively assigned to species (see section below: "Notes on the postlarvae found at Trezen ar Skoden").

Diagnosis. Adults. (1) mouth cone with 8 oral ridges of different length and characterized by posterior sclerotized oral furcae, a telescopic mouth tube, and a well-defined honeycomb sculpture; (2) introvert with 9 rows of scalids; (3) first row with eight clavoscalids that differ between males (multiform, broad or slender, all branched except for the midventral pair) and females (four-segmented, slender, unbranched); (4) second row with 9 four-segmented, leg-like spinoscalids; (5) third row with 7 two-segmented, feather-like scalids; (6) fourth row with 16 spinoscalids of two types: 8 two-segmented, leg-like scalids (type A) alternate with 8 two-segmented spinoscalids with feather-like distal segment (type B); (7) fifth to seventh rows all similar, each row with 30 leg-like, three-segmented scalids; (8) eighth row with 30 very long unsegmented spinoscalids with a small bulbous base; (9) ninth row with 30 small, teeth-like scalids characterized by three cuspid-like protrusions; (10) neck with 8 single trichoscalids alternating with 7 double trichoscalids, with both the single and each of the double trichoscalids protruding from a single, trapezoid trichoscalid plate; (11) trichoscalid plates of the upper appendages of ventrally situated trichoscalids characterized by a short sensory organ with serrated margins and a small, anteroproximal pore; (12) lorica composed of six cuticular plates,

posteriormost region of the dorsolateral plates. Abbreviations: af, anal field; bu, buccal tube; cc, cuticularized crest; cs, clavoscalid; dlp, dorsolateral plate; dp, dorsal plate; lo, lorica; mc, mouth cone; or, oral ridge; sp (and black arrowheads), anterior spike; ss, spinoscalid; tr, trichoscalid; vp, ventral plate.

https://doi.org/10.1371/journal.pone.0250403.g004

with honeycomb sculpturing and bearing 14 large anterior spikes and a small midventral spike; (13) dorsal plate characterized by two narrow, longitudinal stripes spanning laterally along its anterior two thirds; (14) 9 flosculi (4 laterodorsal pairs and 1 dorsal) present posteriorly on the dorsal side of the lorica (dorsolateral and dorsal plates); (15) posterior region of the lorica characterized by a small anal cone, a pair of putative gonopores located postero-dorsally and a pair of ventrally located pores (gland outlets?).

Description. Body ( Figs 1–7 View Fig 1 View Fig 2 View Fig 3 View Fig 4 View Fig 5 View Fig 6 View Fig 7 ). Divided into head (mouth cone and introvert), neck, thorax, and abdomen. The holotypic adult male ( Fig 1 View Fig 1 ) is 235 μm long, including the mouth cone, and 74 μm wide.

Mouth cone (mc, Figs 1 View Fig 1 , 2 View Fig 2 , 4 View Fig 4 , 5 View Fig 5 and 7 View Fig 7 ). Long (ca. 60 μm in length), and with three distinct sections. The proximal section is broad, short and with eight conspicuous, sclerotized oral

arrows point to lorical pores. (D) Close up of the midventral pair of single trichoscalids, each of which protrudes from a plate characterized by a large pore (white double-headed arrow). The inset shows a magnification of the double trichoscalid sensory organ (to), which possesses a small pore (black arrows). (E) Close up of spinoscalids of 9 th row (sr 9) and basal plates, one of each type (bpa and bpb). Note the long hairs (ha) scattered along the length of the distal segments of a spinoscalid of 7 th (?) row. (F) Detail of a cluster of flosculi arranged in a rectangular pattern on the dorsolateral plate. Same specimen as in G. (G) Overview of the posterodorsal region of the lorica. Note the pair of longitudinal stripes (ls) that span the anterior two thirds of the dorsal plate (dp). Black double arrowheads indicate the clusters of flosculi situated on the dorsolateral plates (dlp), while the white double arrowheads point to the small flosculum situated on the dorsal plate. Abbreviations: ac, anal cone; cs, clavoscalid; dlp, dorsolateral plate; fu, oral furca; lo, lorica; mc, mouth cone; or, oral ridge; ss, spinoscalid; sp, anterior spike; tp, trichoscalid plate; tr, trichoscalid; vlp, ventrolateral plate; vp, ventral plate.

https://doi.org/10.1371/journal.pone.0250403.g007

furcae (fu) arranged radially ( Figs 2 View Fig 2 and 7C View Fig 7 ). These eight furcae are of identical structure and they each extend into an oral ridge ( Fig 7A–7C View Fig 7 ). The middle section is long, conical and characterised by the eight oral ridges of different lengths ( Fig 2 View Fig 2 ). Four primary oral ridges (or 1) are long and span the whole middle section, while four secondary oral ridges (or 2) are short and span only the posterior three quarters of the middle section ( Figs 2 View Fig 2 , 4 View Fig 4 and 7A and 7B View Fig 7 ). Both the proximal and middle sections are characterized by a well-defined honeycomb sculpture of the cuticle ( Figs 2 View Fig 2 and 7B View Fig 7 ). The distal section consists of a seemingly short mouth tube (mt), which is slightly bulbous posteriorly and ends with a terminal mouth aperture. However, the mouth tube is telescopic and can extend outside of the mouth cone, significantly increasing its total length ( Fig 5 View Fig 5 ). There are no oral stylets.

Introvert (in, Figs 1 View Fig 1 , 2 View Fig 2 , 4 View Fig 4 , 5 View Fig 5 and 7 View Fig 7 ). Round in shape and characterized by nine rows of scalids arranged radially ( Figs 1 View Fig 1 , 2 View Fig 2 , 4 View Fig 4 and 5–8 View Fig 5 View Fig 6 View Fig 7 View Fig 8 ).

First row (sr1, Fig 8 View Fig 8 ) with eight clavoscalids (cs) that differ between males and females. In females ( Figs 4 View Fig 4 and 5 View Fig 5 ), the clavoscalids are divided into four segments. The first, most proximal segment is relatively short and consists of a conical base that protrudes from the introvert and extends distally into a curved, cylindrical shape with many small papillae arranged anteriorly. The second segment, which is the longest segment of the clavoscalid, is club-shaped and slightly serrated anteriorly. The third segment is very short and thin ( Figs 2 View Fig 2 and 4B View Fig 4 ). The fourth segment is also very short and ends as a spinose tip ( Figs 2 View Fig 2 and 4B View Fig 4 ). In males ( Figs 1–3 View Fig 1 View Fig 2 View Fig 3 and 7 View Fig 7 ) the clavoscalids are multiform. The most ventral pair is exactly as those of the female. The other six clavoscalids possess a robust base and are divided into primary, secondary and tertiary branches. Both the secondary and tertiary branches are broad and flat. However, the former has a thin base and is slightly broader than the latter. The primary branch is three-segmented and very similar to the three most distal segments of the ventral pair of clavoscalids. Indeed, the primary branch possesses distally two short, slightly curved segments: a thin one followed by a terminal spine-like segment.

The second row (sr 2, Fig 8 View Fig 8 ) consists of nine leg-like spinoscalids (ss) divided into four segments ( Fig 2 View Fig 2 ). The first, most proximal segment has a semiround base with a row of papillae arranged laterally on the most proximal region. The base narrows distally to form a cylindrical, short region. The second segment is short and cylindrical with many small papillae. The third segment is slightly thinner and long, representing approximately one half of the spinoscalid. The most distal segment, which represents one quarter of the spinoscalid, is slightly curved and terminates as a spinose tip. Noteworthy, the two midventral and the two ventrolateral spinoscalids of the second row are thinner than all other spinoscalids of the same row. Their bases are characterized by 1–3 small spikes.

The third row (sr 3, Fig 8 View Fig 8 ) is composed of seven short, two-segmented feather-like spinoscalids ( Fig 2 View Fig 2 ). The proximal segment is a small, conical base with several large papillae (up to eight?) arranged anteriorly. The distal segment is relatively long and possesses numerous short, curved hairs.

The fourth row (sr 4, Fig 8 View Fig 8 ) consists of 16 spinoscalids of two types: 8 type A leg-like spinoscalids (sr 4a) alternating with 8 type B feather-like spinoscalids (sr 4b) with numerous short, curved hairs ( Fig 2 View Fig 2 ). The type A spinoscalids are divided into three segments. The first, most proximal segment has a short, round base with several small papillae distributed in a scattered manner. The base narrows distally into a cylindrical, short region. The second segment is thin, serrated posteriorly and rather long, representing half of the total length of the spinoscalid. The third, most distal segment terminates as a thin tip. The type B spinoscalids are two-segmented, each composed of a proximal and a distal segment of similar length. The proximal segment has a round base with several densely distributed papillae. This segment narrows distally to form a cylindrical region with serrated margins. The distal segment has numerous short hairs and, hence, appears feather-like. It terminates in a hook-shaped tip with two short hairs. The fifth to seventh rows (sr 5-7, Fig 8 View Fig 8 ) are each composed of 30 three-segmented, leg-like spinoscalids ( Fig 2 View Fig 2 ). The most proximal segment has a short, narrow base. The middle segment is thin and very long, representing more than half of the total length of the scalid. The most distal segment is relatively long, thin and terminates as a spine-like tip. The two most distal segments have finely serrated margins and several long hairs (ha, Fig 7E View Fig 7 ) scattered along their length. The hairs are only seen by SEM.

The eighth row (sr 8, Fig 8 View Fig 8 ) consists of 30 unsegmented whipe-like spinoscalids with a small bulbous base with a few papillae ( Fig 2 View Fig 2 ). These spinoscalids have finely serrated margins and several long hairs scattered along their length (only seen by SEM), and they terminate as a thin tip.

The ninth row (sr 9, Fig 8 View Fig 8 ) consists of 30 small, teeth-like scalids (well discernible by SEM, Figs 2 View Fig 2 and 7E View Fig 7 ). Each of these scalids possesses an oval anterior edge and three cuspid-like projections that protrude laterally and extend backwards from the posterior edge.

Neck (ne, Figs 2 View Fig 2 and 8 View Fig 8 ). Composed of at least four rows of neck flat plates, which are divided into columns by several longitudinal folds ( Fig 2 View Fig 2 ). A row of 15 small basal plates is present in the most anterior region of the neck, immediately under the ninth row of spinoscalids ( Figs 1D View Fig 1 and 7E View Fig 7 ). This row consists of seven triangular plates (bpa) alternating with eight oval plates (bpb), each with two rows of teeth arranged transversely. The two midventral basal plates are of the latter type (i.e., bpb). Each basal plate is arranged in the center of the neck flat plates. The posterior region of the neck is characterized by 15 trichoscalids (tr) arranged radially: eight single (tr 1) alternating with seven double trichoscalids (tr 2; Figs 1 View Fig 1 , 2 View Fig 2 and 7 View Fig 7 ). The trichoscalids are all flat, with a central ridge, and possess serrated margins with hairs and a blunt tip. The double trichoscalids are composed of two separate appendages, an upper appendage and a lower appendage. The upper appendage is longer (ventrolateral pairs) or slightly longer (lateral pairs) than the lower appendage, which has approximately the same length as a single trichoscalid. Both the single and each of the double trichoscalids protrude from a single trichoscalid plate (tp) with a trapezoid shape; the basal plates of the midventral pair are slightly smaller ( Figs 2 View Fig 2 and 7D View Fig 7 ). Moreover, each ventrolateral single trichoscalid is further characterized by having two sclerotized plates located anteriorly to their trichoscalid plate. Notably, the basal plates of the upper appendages of the double trichoscalids are characterized by a short sensory organ with serrated (toothed) margins and an anteroproximally situated pore, which is only seen by SEM (to; Figs 1D View Fig 1 , 2 View Fig 2 and 7D View Fig 7 ). The trichoscalid sensory organ is situated at the most anterior margin of the upper appendage basal plate. The sensory organs of the ventral double trichoscalid plates are slightly shorter than the ventrolateral ones. The putative sensory organs of the dorsal side could not be observed neither by light nor scanning electron microscopy; their presence/absence remains thus to be determined. In addition, the plate of each midventral single trichoscalid has a large, medially situated pore that is approximately twice the size as the pore on the trichoscalid sensory organs.

Summing up, the number of introvert and neck appendages (cs = clavoscalids,

ss = spinoscalids, tp = trichoscalid plates, tr = trichoscalids) is given in the following formula ( Fig 8 View Fig 8 ):

Introvert: 8 cs; 9 sr 2; 7 sr 3; 8 þ 8 sr 4; 30 sr 5; 30 sr 6; 30 sr 7; 30 sr 8; 30 sr 9;

Neck: 7a þ 8b bp; 8 þ 14 tp; 8 tr 1 ð single Þ þ 7 tr 2 ð double Þ:

Thorax. Short, enclosed in its own cuticle, surrounded externally by the lorica, and without any appendages or segments.

Abdomen. Enclosed in a lorica (lo; Figs 1–7 View Fig 1 View Fig 2 View Fig 3 View Fig 4 View Fig 5 View Fig 6 View Fig 7 ) composed of six cuticularized plates with honeycomb sculpture: one ventral, two ventrolateral, two dorsolateral and one dorsal. Each plate possesses two robust anterior spikes (sp) except for the dorsal plate, which bears four anterior spikes. In total, the anterior edge of the lorica thus has 14 large spikes of equal length, except for one larger spike on each of the dorsolateral plates. In addition, a small midventral spike is present, located between the two large anterior spikes of the ventral plate ( Figs 1D View Fig 1 , 2 View Fig 2 , 7C and 7D View Fig 7 ). The total number of anterior spikes is thus 15.

Notably, the dorsal plate is characterized by two narrow, longitudinal stripes (ls) spanning laterally along its anterior two thirds ( Figs 1B View Fig 1 and 3–7G View Fig 3 View Fig 4 View Fig 5 View Fig 6 View Fig 7 ). These longitudinal stripes appear as surface ridges and their presence gives the impression that the dorsal plate is partially subdivided into three subplates.

A cluster of four flosculi (fl), arranged in a rectangular pattern, is present on each of the dorsolateral plates (dlp). These flosculi are characterized by 5–6 microvilli-like structures covered with cuticle ( Fig 7F and 7G View Fig 7 ). Additionally, a single smaller flosculum, with only 2–3 microvilli-like structures, is found on the dorsal plate.

The postero-dorsal region of the lorica consists of an anal field (af, Figs 1A View Fig 1 , 2 View Fig 2 , 4A View Fig 4 and 6A View Fig 6 ). More specifically, this anus-gonopore region is characterized, both in males and females, by a small anal cone ( Figs 3 View Fig 3 and 7G View Fig 7 ) and a pair of putative gonopores situated posteriorly on the dorsolateral plates (go?; Figs 3 View Fig 3 and 4E View Fig 4 ). Each of the latter plates is furthermore characterized by a cuticularized crest (cc) that spans internally between the putative gonopores and the posterior end of the lorica ( Fig 4A View Fig 4 ). On the ventral side, a large pore (gland outlet?) is situated posteriorly on each margin of the ventral plate (gl?; Figs 2 View Fig 2 and 4D View Fig 4 ) of both males and females.

Internal anatomy ( Figs 2 View Fig 2 and 4–6 View Fig 4 View Fig 5 View Fig 6 ). A long annulated buccal tube (bu) extends between the mouth aperture (mo) and the pharyngeal bulb (pb; Figs 2 View Fig 2 , 4A, 4B View Fig 4 , 5 View Fig 5 and 6D View Fig 6 ). Posteriorly, the pre-pharyngeal armature is characterized by the presence of three buccal furcae arranged radially, which anchor retractor muscles (not shown). In females, the abdominal region is characterized by the presence of two ovaries (ov; Fig 6A View Fig 6 ), each of which may contain oocytes. Males have two large testes (te) containing spermatozoa (sz; Fig 6C View Fig 6 ).