Chevroderma cuspidatum, Ivanov & Scheltema, 2008

Ivanov, Dmitry L. & Scheltema, Amélie H., 2008, NMR solution structures of KAP- 1 PHD finger-bromodomain, Zootaxa 1885, pp. 1-60 : 6-9

publication ID	https://doi.org/ 10.13018/bmr11036
DOI	https://doi.org/10.5281/zenodo.5134419
persistent identifier	https://treatment.plazi.org/id/3076EC0B-FF84-FF85-5DAB-FEA1FDC80812
treatment provided by	Felipe
scientific name	Chevroderma cuspidatum
status	sp. nov.

Treatment

Chevroderma cuspidatum View in CoL n. sp.

( Figures 1A View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 , 4A–C View FIGURE 4 , 24A View FIGURE 24 ; Table 1)

Type material: Holotype USNM 1112616 View Materials . Paratypes: USNM; TAML ; ZMUM Le1-166 (type locality); Le1- 164 (DGoMB, MT2 /2); Le1-165 (DGoMB, MT3 /3) .

Type locality: Gulf of Mexico, 28°13.22'N, 89°29.77'W, 983 m (DGoMB, MT3 /1, 16.06.2000) GoogleMaps .

Material examined: Gulf of Mexico, 564 specimens ( Table 1) .

Diagnosis: Small (<3 mm), slender, smooth, translucent, posterium often longer than trunk; sclerites adpressed; trunk sclerites short (to 120 µm), thin (to 5 µm), curved, sausage-shaped, blade as a small, sharp nipple; sclerites fringing knob in single row, extending beyond knob; 2 rows oral shield sclerites indistinct.

Etymology: L. cuspidatus -a, -um = pointed.

Description: External appearance ( Figs. 1A View FIGURE 1 , 2A, B View FIGURE 2 ): Nearly transparent, smooth body <3mm long and narrow, junction between trunk and shank clear owing to internal organs seen through transparency of trunk as well as usually by body shape, posterium/trunk length index 0.85–1.30; holotype length 2.4 mm, anterium <0.1 mm, trunk 1.3 x 0.4 mm, shank 0.8 x 0.2 mm, knob 0.3 mm, posterium/trunk index 0.85; oral shield small, often exposed, oral shield sclerites scarcely evident; trunk sclerites at 45º angle to body axis on trunk ( Fig. 2A, B View FIGURE 2 ), diverging along ventral midline ( Fig. 2A View FIGURE 2 ), converging along dorsal midline; shank sclerites adpressed, noticeably shorter than on trunk; knob cone-shaped, fringing sclerites in single row extending beyond end of cone.

Sclerites ( Figs 2F, G View FIGURE 2 , 3 View FIGURE 3 , 4A–C View FIGURE 4 ): General: anterium through shank with slightly raised, distal, pointed blade, or nipple; base curved toward body ( Fig. 3J View FIGURE 3 ); from ventral anterium, dorsal trunk, and ventral trunk, sausageshaped, of even width; juveniles as in adults but smaller ( Fig. 2G View FIGURE 2 ). Beside oral shield ( Fig. 3A View FIGURE 3 ): asymmetrical, curved, rounded basally and distally, groove indistinct, thin, to 36 x 16 x 2 µm, thickest medially. Dorsal to oral shield ( Fig. 3B View FIGURE 3 ): grooved thin scales tapered to blunt point, to 30 x 14 x 1 µm. Dorsal and lateral anterium ( Fig. 3C View FIGURE 3 ): of even width or basally broad, most with distinct, medially offset groove, proximal end angular, to 90 x 18 x 4–5 µm, gradually becoming narrower and thicker ventrally ( Fig. 3D View FIGURE 3 ), similar to ventral trunk sclerites. Ventral trunk ( Fig. 3E View FIGURE 3 ): shorter than dorsal trunk, to 80 x 15 µm. Dorsal trunk ( Fig. 3F View FIGURE 3 ): as in diagnosis, to 120 x 20 x 5 µm, thickest medially beside distinct or indistinct groove. Shank ( Fig. 3G View FIGURE 3 ): from small sausage-shaped to long and tapered from angular proximal end to distal end, thickest medially, to 140 x 30 x 7 µm. Fringing ( Fig. 3I View FIGURE 3 ): long, straight, narrow, some with distinct waist, to 190 x 10 µm, most to 4 µm thick but up to 7 µm. Knob ( Fig. 3H View FIGURE 3 ): short, extremely narrow to somewhat proximally broadened needles, to 90 x 7 x 2 µm.

Radula and jaws: 2 examined. Jaws 210 x 75 µm ( Fig. 2D View FIGURE 2 ); radula teeth 53 µm long, serrated membrane about 30 µm, situated almost in middle of tooth; central plate symmetrical, to 25 µm ( Fig. 2E View FIGURE 2 ).

Distribution: Known only from the continental slope of the Gulf of Mexico between 357 and 1,032 m ( Fig. 24A View FIGURE 24 ; Table 1).

Remarks: Chevroderma cuspidatum inhabits shallower depths than other known Chevroderma species. It is the only Chevroderma species in the Gulf of Mexico. C. cuspidatum may be endemic to the Gulf of Mexico. The closely adpressed, sausage-shaped sclerites with a sharp, distal nipple diverge morphologically from all other Chevroderma sclerites, although a similar morphology occurs in two undescribed Pacific species. In outline they are similar to those of Prochaetoderma ? atlanticum Scheltema & Ivanov, but having a groove and chevron-shaped growth lines, as well as the angled base of Chevroderma species on anterium and shank sclerites. We interpret the slightly raised, sharp nipple as all that remains of a blade on these otherwise closely adpressed sclerites ( Figs 3J View FIGURE 3 , 4A – C View FIGURE 4 ).