Pycnocraspedum phyllosoma ( Parr, 1933 )

Schwarzhans, Werner W., Psomadakis, Peter N. & Nielsen, Jørgen G., 2025, Revision of the bathydemersal fish genus Pycnocraspedum (Ophidiidae; Teleostei), with description of two new species, Zootaxa 5636 (3), pp. 443-472 : 462

Pycnocraspedum phyllosoma ( Parr, 1933)

Figures 1 , 3 , 4 , 5 , 9 , 12 ; Tables 1, 2

Neobythites phyllosoma Parr, 1933: 44–46 , fig. 20, off Turks Island, Bahamas, 21°30'N, 71°11'W, Pawnee St. 52. Pycnocraspedum phyllosoma ( Parr, 1933) : Nielsen et al. (1999), Evseenko & Okiyama (2006), Prokofiev (2022).

Material examined (4 specimens, 130–355 mm SL): 1 specimen USNM 227413, 230 mm SL, 20.85°N 71.52°W (off Caicos Island), RV Oregon cr. 101, st. 5427, 40 ft shrimp trawl, 512–576 m, 27 May 1965 ; 1 specimen USNM 421586, 355 mm SL, 12.0832°N 68.8991°W (off Curacao), RV Curasub , Deep Reef Observation Project ( DROP), May 2013 ; 1 specimen USNM 412587, 295 mm SL, 12.0832°N 68.8991°W (off Curacao), RV Curasub , Deep Reef Observation Project ( DROP), May 2013 ; 1 specimen USNM 470952, 130 mm SL, 25.97°N 78.48°W, RV Gerda cr. 6720, st. 925, 10 Otter trawl, 439–457 m, 29 September 1967 .

Diagnosis. Precaudal vertebrae 12–13, total vertebrae 52–54; dorsal-fin rays 96–101; anal-fin rays 70–73; pectoral-fin rays 25–27; long gill rakers on first gill arch 4–5; pseudobranchial filaments 5–6; 3–4 dorsal-fin rays in front of first vertebra; HL 22.7–26.5% of SL; body depth at vent 21–23% of SL; predorsal length 18.8–23% of SL; rear margin of preopercle with 3 spines, 2 lower and 1 upper, with flashy flap between spines 2 and 3; transversal scale rows above origin of anal fin 72–78, and above lateral line 20–21; otolith (23.3 mm in length) OL:OH = 2.15, dorsal rim smooth, ventral rim symmetrical to dorsal rim.

Description. Relatively robust fish with stout tapering tail and rounded snout.Maximal size of fishes investigated 355 mm SL. Preopercular rim with 3 spines, 2 spines positioned at bend and 1 further up, with fleshy flap in between spines 2 and 3.

Meristics (4 specimens, not including juvenile holotype of P. phyllosoma ): precaudal vertebrae (12–13); total vertebrae 52–54; dorsal-fin rays 96–101; anal-fin rays 70–73; pectoral-fin rays 25–27; caudal-fin rays 10; D/V = -3– -4; D/A = 29–30; V/A = 16–17; long gill rakers on first gill arch 4–5; pseudobranchial filaments 5–6; transversal scale rows above origin of anal fin 72–78, and above lateral line 20–21; pyloric coeca 18–21.

Morphometrics (4 specimens) in % of SL: HL 22.7–26.5; body depth at vent 21–23; diameter of eye 4.4–5.0; upper jaw length 11.4–14.5; interorbital width 6.5–8.1; pelvic-fin base to anal-fin base 22.2–26; predorsal length 18.8–23; preanal length 41.7–51; prepelvic length 19.1–27; pectoral-fin length 14.5–17.2; pelvic-fin length 11.5– 13.

Otolith morphology (1 specimen from specimen of 295 mm SL). Size 23.3 mm in length; OL:OH = 2.15; OH: OT = 2.4. Moderately thin, oval, elongated, anteriorly moderately rounded, posteriorly distinctly pointed, anterior and posterior tips positioned along median sulcus axis. Dorsal rim regularly curved, relatively high, smooth; ventral rim about as deep as dorsal rim high, smooth. Inner face distinctly bent/convex in horizontal and vertical directions, with long, undivided sulcus reaching relatively close to anterior and posterior rims of otolith. Sulcus with shallow, undivided, uniform colliculum with slightly concave dorsal rim and slightly convex ventral rim and rounded anterior and posterior tips. OL:CL = 1.25. Dorsal field smooth, without depression; ventral field smooth. Outer face nearly flat, rather smooth.

Coloration. Live coloration pale with small dark spots in small individuals ( Girard et al. 2023). Color of preserved large specimens medium to dark brown, with dusty dark brown coloration on scales.

Discussion. Pycnocraspedum phyllosoma resembles P. armatum in many traits and differs only in relatively subtle features such as the number of spines on the preopercle (3 vs. 4), 72–78 transversal scale rows (vs. 60–68), 18–21 pyloric coeca (vs. 12–16), and a relatively dark body coloration. Its otoliths show a symmetrical shape of dorsal and ventral rim while in other species the ventral rim is shallower than the dorsal rim or vice versa in P. squamipinne , where the ventral rim is deeper than the dorsal rim.

Distribution. Pycnocraspedum phyllosoma is the only species of the genus known from the tropical West Atlantic while all other extant species of Pycnocraspedum occur in the Indo-West Pacific. The 136 mm SL holotype was caught pelagic in the Turks Island Passage, Pawnee St. 52.

Figures

FIGURE 1. Radiograph figures of selected specimens of the genus Pycnocraspedum to visualize position of dorsal-fin rays in relation to first vertebra; “1” denotes the first dorsal-fin ray above the first vertebra; numbers with negative denotation represent dorsal-fin rays in front of the first vertebra. 1A) Pycnocraspedum armatum, USNM 227390; 1B) Pycnocraspedum phyllosoma USNM 227413; 1C) Pycnocraspedum squamipinne, ZMUC P771871; 1D) Pycnocraspedum fulvum (holotype), BSKU 27497.

FIGURE 3. Detail figures and drawings of preopercular spines and lower preopercular pores in Pycnocraspedum; preopercular spines are numbered from 1 through 4 from the lower angle of the preoperculum upwards; abbreviation lpp = lower preopercular pore. 3A–3B) Pycnocraspedum armatum, USNM 227412, 3A1-3A2 specimen 1 left side, 3A3 specimen 1 right side (mirror imaged), 3B specimen 2; 3C–3D) Pycnocraspedum phyllosoma, 3C USNM 421587, 3D USNM 421586; 3E) Pycnocraspedum fulvum (holotype), BSKU 27497; 3F–3G) Pycnocraspedum africanum sp. nov., 3F holotype, MNHN 2000-5691, 3G paratype, MNHN 2000-5692; 3H) Pycnocraspedum rowleyensis sp. nov., holotype, WAM I.28059.021; 3I–3K) Pycnocraspedum squamipinne, 3I lectotype, BMNH 1890.7.31.1, 3J ZMUC P771871, 3K ZMUC P771737.

FIGURE 4. Head and body squamation details in Pycnocraspedum phyllosoma, USNM 421587; abbreviations used: aip-1–aip- 3 = anterior infraorbital pores 1–3, asp = anterior supraorbital pore, pip-1 = posterior infraorbital pore 1; preopercular spines numbered. 4A) head squamation in lateral view; 4B) trunk squamation and every 10 scale row count marked by white dot; 4C) snout squamation and pores detail; 4D) head squamation in ventral view.

FIGURE 5. Otoliths, inner faces (if not noted otherwise) shown from right side. 5A–5C) Pycnocraspedum africanum sp. nov., 5A holotype, MNHN 2000-5691 (5A2 dorsal view), 5B paratype MNHN 2000-5692, 5C tentatively assigned specimen, IRSNB (5C2 dorsal view, 5C3 anterior view); 5D–5E) Pycnocraspedum armatum, 5D USNM 227412 (5D2 ventral view), 5E USNM 227390 (5E2 ventral view); 5F) Pycnocraspedum fulvum (holotype), BSKU 27497 (5F2 ventral view, 5F3 anterior view); 5G) Pycnocraspedum rowleyensis sp. nov., holotype, WAM I.28059.021 (5G2 ventral view); 5H) Pycnocraspedum phyllosoma, USNM 421587 (5H2 ventral view, 5H3 anterior view); 5I–5K) Pycnocraspedum squamipinne, 5I lectotype, BMNH 1890.7.31.1 (5I2 ventral view), 5J ZMUC P771871, 5L ZMUC P771739 (5L2 ventral view), 5K ZMUC P771738 (5K2 ventral view); 5M) †Pycnocraspedum cetonaense (holotype) SMF P.5694 (5M2 dorsal view, 5M3 anterior view).

FIGURE 9. Pycnocraspedum phyllosoma (Parr, 1933); 9A, 9C) USNM 412587, 295 mm SL, 12.0832°N 68.8991°W; 9B) radiograph of USNM 227413, 230 mm SL, 20.85°N 71.52°, 512–576 m.

FIGURE 12. Geographic distribution of the species of Pycnocraspedum. One symbol can represent more than one location.