Leiocanthus nagini sp., 2016

Sørensen, Martin V., Gąsiorowski, Ludwik, Randsø, Phillip V., Sánchez, Nuria & Neves, Ricardo C., 2016, First report of kinorhynchs from Singapore, with the description of three new species, Raffles Bulletin of Zoology 64, pp. 3-27 : 20-25

publication ID	https://doi.org/ 10.5281/zenodo.4502533
publication LSID	lsid:zoobank.org:pub:819AC644-37BC-43DB-8E11-984D77804AFE
DOI	https://doi.org/10.5281/zenodo.4776238
persistent identifier	https://treatment.plazi.org/id/03D187A7-DA26-4E1B-39C1-FF55FD6FFBA8
treatment provided by	Carolina
scientific name	Leiocanthus nagini sp.
status	sp.

Treatment

Leiocanthus nagini sp. nov.

( Figs. 11–13 View Fig View Fig View Fig )

Material examined. Holotype adult male, collected from sand with mud on 16 May 2014, at station SI-05 ( Fig. 1 View Fig , Table 1), at 52 m depth, at the locality “ Eastern Fairway ” southeast of Singapore Island (01°15.589’N 103°56.680’E), mounted in Fluoromount G, deposited at the Lee Kong Chian Natural History Museum, under catalogue number ZRC. MIS.0004. GoogleMaps Additional, non-type material, includes one adult female, collected from sand with mud on 16 May 2014, at station SI-03 ( Fig. 1 View Fig , Table 1), at 9 m depth, between Bedok Jetty and Sungei Bedok in the southeast part of Singapore Island (01°18.387’N 103°57.591’E), and mounted for SEM. GoogleMaps

Diagnosis. Leiocanthus without middorsal elevations. Paradorsal setae present on segments 2–9, paired ones on segment 4. Tergal anterior margin of segment 1 strongly denticulated and followed by a broad, ornamented area. Dorsal and ventral sides on segment 10 with longitudinal cuticular thickenings, visible with LM and SEM. Type 1 sensory spots present on segments 1–10, but not detectable on segment 11 .

Etymology. The species name, nagini , is the female version of Nāgá – the Sanskrit word for a group of divine dragons or serpent deities known from Hindu and Buddhist mythology. Nagini is furthermore Lord Voldemort’s serpent, known from J. K. Rowling’s Harry Potter novels.

Description. The single specimen available for SEM was not suitable for introvert examinations, and detailed information on number and arrangement of scalids and oral teeth was thus not possible to obtain.

Neck with four dorsal and two ventral placids ( Figs. 11A, B View Fig , 13A, B View Fig ). All placids are thick and hard, with a depressed surface, and articulating with the anterior edge of the first trunk segment. Dorsal placids are rectangular and of similar size, whereas the ventral ones are broader and curve towards the lateral sides. Cuticular folds appear between dorsal and ventral placids. Trichoscalid plates are absent.

Trunk consisting of 11 segments ( Figs. 11A, B View Fig , 12A, B View Fig ). First segment with one tergal and three sternal plates ( Figs. 11A, B View Fig , 13A, B View Fig ); segments 2–11 with one tergal and two sternal plates ( Figs. 11A, B View Fig , 12B View Fig ). Dimensions and measurements of holotype are summarised in Table 6, and distribution of spines, sensory spots and setae in Table 7. The segment width is nearly constant along the trunk, reaching the maximum width at segment 5 and tapering slightly from this segment towards the posterior ones. Pachycycli of tergal and sternal plates are well-developed, with regular sized peg-and-socket joints from segments 2–10. Hairy tergosternal junctions, with numerous short cuticular hairs present on segments 2–10. Conspicuous, oval glandular cell outlets present in laterodorsal and ventromedial positions on segments 2–10 ( Fig. 11A, B View Fig ). Indistinct, rounded muscular scars present in laterodorsal and ventromedial positions on segments 2–10. One pair of laterodorsal and ventrolateral cuticular ridges present on segments 2–10. One pair of apodemes near the anterior margins of segments 9 and 10 ( Fig. 11A View Fig ).

Segment 1 with anterolateral margins of tergal plate projecting into horn-like extensions. Tergal, anterior margin of the segment strongly denticulated, followed by a broad, longitudinal cuticular ornamentation ( Figs. 11B View Fig , 12E View Fig , 13A View Fig ). Posterior margin of dorsal plate smooth, without middorsal structure specialisation (middorsal process or elevation) or intracuticular atria. Tergal plate with one pair of subdorsal glandular cell outlets, one pair of paralateral setae ( Fig. 13B View Fig ) and three pairs of sensory spots: one pair in subdorsal and two pairs in laterodorsal positions. Sensory spots on this and all following segments belong to type 1, which are rounded and small, consisting of several small cuticular papillae around a central collar of wider papillae. Ventral side with two episternal plates and one trapezoidal midsternal plate, the latter one overhanging the anterior edge of the segment ( Figs. 11A, C View Fig , 13B View Fig ). Anterior margin of each sternal plate is ornamented and followed by a contiguous depressed area ( Fig. 13B View Fig ). Each episternal plate with a glandular cell outlet in the medial region and two ventromedial sensory spots. Pectinate fringe on both dorsal and ventral sides thin, only visible with SEM. Conspicuous parallel, cuticular wrinkles present in the posterior parts of tergal and episternal plates, but absent in the midsternal one.

Segment 2 without middorsal elevation or intracuticular atria at the posterior margin of the dorsal plate. Tergal plate with a single paradorsal seta, and paired setae in laterodorsal and lateroventral positions. Paired sensory spots present in subdorsal and laterodorsal positions. Dorsal side with short secondary pectinate fringes in the anterior part of the segment, present from the tergosternal junction to the laterodorsal longitudinal ridge. Sternal plates with one pair of ventromedial sensory spots. Males with a pair of thick ventromedial tubes ( Fig. 11A View Fig ). Females instead with a pair of ventrolateral setae ( Figs. 11C View Fig , 12F View Fig ). Ventral side with secondary pectinate fringe similar to that on the dorsal side, stretching from the tergosternal junction to the ventromedial cuticular ridge. Posterior margin of tergal and sternal plates with conspicuous parallel, cuticular wrinkles. Tergosternal junctions with numerous short cuticular hairs. Muscular scars and glandular cell outlets present in laterodorsal and ventromedial positions. Pachycycli of tergal and sternal plates well-developed, with regular sized peg-and-socket joints. Pectinate fringe as on the preceding segment.

Segment 3 without middorsal elevation or associated intracuticular atria on tergal plate. A single paradorsal seta, one pair of laterodorsal setae, and two pairs of laterodorsal sensory spots are present on tergal plate. Both pairs of laterodorsal sensory spots are located mesially to the laterodorsal setae. Lateroventral setae absent. Sternal plates with one pair of ventromedial setae and sensory spots, with the sensory spots located lateral to the setae ( Fig. 12F View Fig ). Otherwise similar to preceding segment.

Segment 4 without middorsal elevation or associated intracuticular atria on tergal plate. Paired setae present in paradorsal, laterodorsal and lateroventral positions. Three pairs of sensory spots present, one in subdorsal and two in laterodorsal positions, all of them located mesially to the laterodorsal setae. Sternal plates as on segment 3. Otherwise similar to preceding segments.

Segment 5 with tergal plate ( Fig. 13C View Fig ) almost similar to that of segment 3 ( Fig. 11B View Fig ), but only with a single pair of laterodorsal sensory spots. Sternal plates similar to those on segment 3, except for the presence of paired ventrolateral setae. Otherwise similar to preceding segments.

Segment 6 with tergal plate ( Figs. 11B View Fig , 12D View Fig , 13C View Fig ) almost similar to that of segment 4, but with a single paradorsal seta. Sternal plates same as those of segment 3, but with the ventral setae in females displaced to a ventrolateral position ( Figs. 11A View Fig , 13D View Fig ). Otherwise similar to preceding segments.

Segment 7 with tergal and sternal plates ( Figs. 11A, B View Fig , 12D View Fig , 13D View Fig ) almost as those of segment 5, except for the ventral setae that are displaced to a ventrolateral position ( Figs. 11A View Fig , 13D View Fig ). Otherwise similar to preceding segments.

Segment 8 with tergal plate ( Figs. 11B View Fig , 12C View Fig , 13F View Fig ) similar to that of segment 6, but with one additional pair of laterodorsal sensory spots, making it three laterodorsal pairs in total ( Fig. 11B View Fig ). Sternal plates as those on segment 3. Otherwise similar to preceding segments.

Segment 9 with tergal ( Figs. 11B View Fig , 12C View Fig , 13F View Fig ) and sternal plates similar to those of segment 3. Protonephridial opening in paralateral position, with the pore surrounded by a few short cuticular hairs; opening not sieve-like. Paired apodemes (or anteromesial thickenings of ventral pachycycli) present near the anterior margin of segment ( Fig. 11A View Fig ). Otherwise similar to preceding segment.

Segment 10 without dorsal structures ( Figs. 11B View Fig , 12G View Fig ). Tergal plate with one pair of lateroventral setae and a pair of laterodorsal sensory spots. Sternal plates with ventrolateral setae. Ventromedial sensory spots not found. Paired apodemes present near the anterior margin of the segment ( Figs. 11A View Fig , 13E View Fig ). Lateral margins of tergal and sternal plates with conspicuous, longitudinal cuticular thickening visible with LM and SEM ( Figs. 12G View Fig , 13E View Fig ). Otherwise similar to preceding segment.

Segment 11 with a pair of lateral terminal spines ( Fig. 11A, B, D View Fig ). Males with two pairs of penile spines and genital pores surrounded by a tuft of long hairs. Posterior segment margin with characteristic, irregularly fringed shape ( Fig. 13E View Fig ).