Bathytoshia brevicaudata ( Hutton, 1875 )
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publication ID |
https://doi.org/10.3897/zse.101.164102 |
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publication LSID |
lsid:zoobank.org:pub:05A33FE9-5BF1-4C9F-8432-92E172DF5DEA |
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DOI |
https://doi.org/10.5281/zenodo.17633831 |
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persistent identifier |
https://treatment.plazi.org/id/3C72E54E-CA8D-53AF-914A-A7B59506CECF |
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scientific name |
Bathytoshia brevicaudata ( Hutton, 1875 ) |
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Bathytoshia brevicaudata ( Hutton, 1875) View in CoL
Diagnosis.
Large, plain-colored stingray with broad rhombic disc, short snout; dorsal surface greyish-brown, ventral surface whitish with grey margins; oblique white spots and paired anterolaterally-directed white pores at pectoral-fin bases dorsally; pelvic fins small; tail dusky, midline preceding caudal sting bearing row of spear-shaped or star-based thorns and tubercles, post-sting portion blackish distally and covered with sharp thornlets.
Description.
Based on 2 specimens, 1,810–1,955 mm TL. Proportional measurements and counts are given in Table 1 View Table 1 .
Body large and flattened but thick, with a broad rhombic disc (Figs 1 View Figure 1 , 2 View Figure 2 ). Disc width 1.2 (female) – 1.4 (male) times its length (Table 1 View Table 1 ). Back smooth with large backward-pointing tubercles (9 in male, 3 in female); tail mid-line with similar tubercles extending anterior to caudal sting (Figs 1 View Figure 1 , 2 View Figure 2 ). Snout short and blunt, length 0.22–0.23 times disc length, with irregularly distributed upright tubercles bearing blunt stellate bases, clustered discontinuously between snout tip and anterior orbital margins (Fig. 3 A, B View Figure 3 ). Eyes small, length of orbit and spiracle 2.2 times (male) and 2.7 / 1.7 times (female) of snout length; interorbital space broad, up to 6 times orbit length (Table 1 View Table 1 ).
Pectoral fins broad; anterior margins nearly straight; distal apex narrowly rounded; posterior margins smoothly convex; posterior insertion deeply notched; posterior angle bluntly pointed. Pectoral insertions slightly exceeding interorbital width. Pelvic fin origin slightly anterior to pectoral insertion; extending posteriorly beyond pectorals; anterior margin and lateral margins nearly straight, lateral and posterior angles smoothly rounded; pelvic insertion deeply notched (Figs 1 View Figure 1 , 2 View Figure 2 ). Claspers (male) moderately elongate, length 0.24 times tail length; tips not reaching caudal sting (Table 1 View Table 1 ).
Tail stout and tapered (not whip-like), short to moderately elongate, length 0.8–1.0 times disc width (males 0.8, females 1.0, estimated); base broad and depressed, width 1.4–1.6 times depth (Table 1 View Table 1 ); single caudal sting positioned midway, immediately posterior to dorsal thorn row comprising 15 densely arranged enlarged thorns with sharp-tipped projections from base (male) or 7 sparsely spaced thorns (female) (Fig. 3 C, D View Figure 3 ); lateral serrated thorns upright, blunt, stellate-based, numerous, extending to tip; minute thorns densely cover dorsal surface from posterior to caudal sting, extending to terminus; ventral fold distinct (Fig. 3 E, F View Figure 3 ), moderately long (0.3 times tail length) (Table 1 View Table 1 ), originating slightly posterior to caudal sting origin, extending toward tip but falls far of terminus; dorsal fold degenerated (Fig. 3 E, F View Figure 3 ).
Labial furrows deep; lower jaw weakly convex. Nasal curtain square-shaped, very broad, with margin fringed; nostrils oval, oblique (Fig. 4 A, B View Figure 4 ). Mouth small (Figs 1 View Figure 1 , 2 View Figure 2 ); floor of mouth with transverse series of 5 (female) or 7 (male) oral papillae; midregion with 3 (male) or 4 (female) prominent elongated papillae, lateral papillae shorter, 1–2 per side (Fig. 4 C, D View Figure 4 ). Teeth small, granular, with 31 (male) and 33 (female) rows on upper jaws, and 34 (male) and 37 (female) rows on lower jaws, arranged in an interlocking pavement pattern. Upper and lower teeth similar, with sharp cusps in male while rounded in female (Fig. 4 C, D View Figure 4 ).
The male specimen ZJOUMBM F 00035 possesses claspers measuring 257 mm in length, situated on the posteromedial aspect of the pelvic fins (Suppl. material 1: fig. S 5). The dorsal surface of the claspers exhibit a slate-gray coloration, while the ventral surface appears pinkish due to subcutaneous hemorrhaging, with a seminal groove on the dorsal side. The claspers are robust, rigid, and exhibit a fully calcified structure, confirming the adult status of the specimen.
Color.
Dorsal surface pale grey, darkest above eyes and on tail tip, with 26–30 (female) or 21–24 (male) white pores arranged diagonally from pectoral fin bases toward pectoral fin leading edges; spiracles white internally; lateral head-encircling pore rows white; disc margin grey; ventral surface white (Figs 1 View Figure 1 , 2 View Figure 2 ).
To aid in the morphological identification of genus Bathytoshia , we propose the following diagnostic key, building upon the taxonomic framework of Last et al. (2016 b):
Feeding habits.
Dissection of the female specimen revealed stomach contents (Fig. 5 View Figure 5 ) comprising fragmentary prey remains, specifically two Branchiostegus japonicus (Houttuyn, 1782) (Horsehead Tilefish) , one Trachurus japonicus (Temminck & Schlegel, 1844) (Japanese Jack Mackerel) , one Neobythites Goode & Bean, 1885 sp. , and three longline fishhooks. The hooks included one circle hook (front length (FL) 20.2 mm, width (WD) 25.0 mm, gap (GP) 12.4 mm, shaft length (SL) 38.7 mm, offset 10 °) piercing the gastric wall into the liver (Suppl. material 1: figs S 6, S 7) and two J hooks (FL 17.8 mm, WD 17.8 mm, GP 15.2 mm, SL 42.6 mm) lodged within the stomach lumen.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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