Galeus priapus, Séret, Bernard & Last, Peter R., 2008

Séret, Bernard & Last, Peter R., 2008, Galeus priapus sp. nov., a new species of sawtail catsharks (Carcharhiniformes: Scyliorhinidae) from New Caledonia, Zootaxa 1813, pp. 19-28 : 21-26

Galeus priapus sp. nov.

Figs 2 and 3 , Tables 1–3

Phallic catshark (English), chien Priape (French)

Galeus sp. n.: Séret, 1994: 7 (listed).— Grandperrin et al., 1995: table 4, p. 33 (listed).

Material examined (11 type specimens). Holotype: HALIPRO 1: stn. CH 872, 23°03’S, 166°56’E, 620–700 m depth, bottom trawl, R.V. “ Alis ”, 30 March 1994, adult male 391 mm TL ( MNHN 1997-3534).

Paratypes: (10 specimens): New Caledonia: BATHUS 3: stn. CC 848, 23°02’S, 166°52’E, 690–700 m depth, shrimp trawl, R.V. “ Alis ”, 1st December 1993, 4 paratypes: 1 adolescent male 376 mm TL ( MNHN 1997-3533), 1 mature male 383 mm TL ( MNHN 1997-3530) and 2 females 354 mm TL ( MNHN 1997-3531) and 430 mm TL ( MNHN 1997-3552).— HALIPRO 1: stn. CH 872, 23°03’S, 166°56’E, 620–700 m depth, bottom trawl, R.V. “ Alis ”, 30 March 1994, 1 paratype female 388 mm TL ( MNHN 1997-3535).— Stn CH 873, 23°03’S, 166°53’E, 640–680 m depth, 30 March 1994, 3 paratypes: 1 male 375 mm TL ( MNHN 1997- 3536), 1 female 455 mm TL ( MNHN 1997-3537) and 1 adult male 446 mm TL ( CSIRO H 6622-01).— Stn CH 874, 23°06’S, 166°53’E, 708–830 m depth, 30 March 1994, 1 paratype female 295 mm TL ( MNHN 1997-3538). Vanuatu: MUSORSTOM 8, stn CP 1123, 15°07’S, 166°55’E (Big Bay, Espiritu Santo Isl.), 262– 352 m depth, beam trawl, R.V. “ Alis ”, 9 October 1994, 1 paratype female 327 mm TL ( MNHN 1997-3529).

Non-type material (7 specimens). New Caledonia: BATHUS 3: stn. CC 841, 23°02.92’S, 166° 53.10E, 640–680 m depth, shrimp trawl, R.V. “Alis”, 30 November 1993, 2 females 357–367 mm TL and 2 males 394–410 mm TL ( MNHN 2002-1150) - BATHUS 3: stn. CP 832, 23°03.07’S, 166°53.57’E, 650–669 m depth, beam trawl, R.V. “Alis”, 30 November 1993, 2 males 373–430 mm TL and a juvenile male 320 mm TL ( MNHN 2002-1151).

Diagnosis. A small, slender Galeus with the following combination of characters: claspers extremely long and slender in adult males, distal tips extending to near anal origin or beyond, their outer length 9.2–11.2% TL, 7.2–8.7 times base width; clasper without hooks or spiny denticles; exorhipidion greatly elongated, about 4 times spiracle length when fully developed; anterior inner margin of pelvic fin not fused to clasper; anal fin relatively small, length 9.8–12.0% TL; posterior anal-fin margin 4.7–5.9% TL, 1.4–1.8 in anterior margin of second dorsal fin; prepectoral length relatively short, about 17.8–19.4 %TL; labial furrows moderately long, not confined to mouth corners; enlarged denticle crest of upper caudal fin originating almost over origin of ventral caudal lobe, no abrupt demarcation between denticles of crest and those of caudal peduncle; denticles forming 2–5 central rows of denticles between larger oblique lateral rows near crest origin; no subcaudal crest; anterior margin of pectoral fin black; anterior half of dorsal fins almost entirely dark or dusky; precaudal centra 81–86.

Description. Body very slender, head height 7.0 (7.1–8.5)% TL; abdomen long, pectoral to pelvic space 14.2 (10.9–16.6)% TL, 1.43 (1.12–1.68) of head length; pelvic to anal space long 1.14 (0.98–1.43) of anal-fin base; caudal peduncle elongate, anal to caudal space 0.71 (0.59–0.96) of anal-fin base; peduncle not greatly compressed, width 1.42 (1.31–2.00) in height. Snout long parabolic, tip narrowly rounded; preoral length 7.9 (6.9–7.4)% TL, 1.01 (0.93–1.06) times mouth width; prenarial snout 1.52 (1.14–1.66) times eye length. Eyes small, length 3.3 (2.6–3.5)% TL, 6.15 (5.31–7.11) in head length in adults; eyes dorsolateral on head, with well-developed subocular ridges.

Mouth moderately large and long, broadly arched, width 7.8 (6.9–8.2)% TL, 2.44 (1.94–2.88) times its length; labial furrows well developed, lower furrows only slightly shorter than mouth length, not extending forward to symphysis. Teeth with 3–5 cusps, mainly tricuspidate in holotype and other adults; cusps adjacent central cusp well developed, about half length (slightly less at centre of mouth) of central cusp, more than half in young; in 60 (57) rows in upper jaw; 60 rows in lower jaw.

Denticles on sides tricuspidate, semi-erect, slightly imbricated; crown broadly parabolic with a long, broad-based central cusp and very short or rudimentary lateral cusps; pronounced longitudinal ridge along midline of crown including central cusp. Supracaudal crest well developed, about equal in length to anterior margin of pectoral fin; origin of crest indistinct, anteriorly pre-crest denticles progressively increasing in size and becoming more oblique on crest; crest evident above origin of lower caudal lobe but becoming elevated slightly behind this point (over origin in one paratype), elevated portion demarcated by strip of naked skin; denticles in mainly 3–4 central rows (in juveniles mainly 2–3 anteriorly, increasing to 3–5 on middle of crest), rows bordered by larger, more posterolaterally directed lateral denticles (usually about twice size of those centrally); subcaudal crest absent.

Claspers subcylindrical, barely tapering, extremely long and slender when fully developed, outer length 9.8 (9.2–11.2)% TL, inner length 10.7 (10.0–12.3), width 2.15 (1.68–1.90) times spiracle length; distal tips reaching to anal-fin origin or beyond; tips somewhat filamentous, twisted slightly (variable in paratypes); pelvic apron not developed, anterior inner margin of pelvic fin not fused to clasper, dorsolateral margin of clasper connected to ventral surface of pelvic fin by a long elastic membrane; glans long, more than half length of clasper from apopyle to tip; ventral and lateral surfaces densely covered with imbricated, erect to semi-erect denticles that are directed toward clasper base; denticles crowns smooth, subcircular, those near base without cusps, those near apex with very short cusps; no hooked denticles or clasper hooks; cover rhipidion very small, pseudosiphon small; with two distinct terminal lobes, exorhipidion elongate, semi-tubular, greatly expanded distally, forming deep concavity with inner lobe in holotype and largest male paratype (shorter exorhipidion and weak concavity in smaller male paratypes with firm claspers considered to be state of development); pseudopera below origin of exorhipidion; no envelope present anterior to hypopyle; rhipidion extending along most of hypopyle.

Dorsal fins variable in shape, first slightly larger than second, originating over hind half of pelvic fins; second inserted well behind insertion of anal fin. Pectoral fins moderately large, broad, anterior margin 10.8 (10.5–12.0)% TL. Pelvic fins small, low, angular, length 12.7 (10.8–12.9)% TL. Anal fin very short, base 8.8 (8.0–10.2)% TL, 1.48 (1.24–1.73) in interdorsal space; origin about under middle of interdorsal space; analfin height 2.74 (2.37–3.28) in base length.

Monospondylous centra 38 (35–36); precaudal centra 85 (81–86); total (134–144).

Coloration (from preserved specimens). Dark to pale grey above; paler ventrally; four distinct (indistinct in some paratypes), darker dorsal saddles situated beneath each dorsal fin and on tail; saddle below first dorsal fin commencing near fin origin, its width slightly narrower than fin base, extending ventrally almost to lateral midline; saddle below second dorsal fin similar, about as wide as fin base; saddle above apex of lower lobe of caudal fin also of similar size and almost reaches lateral midline of fin; broad saddle before terminal lobe of caudal fin, width subequal to length of first dorsal fin, extending well below lateral midline of fin. Dorsal fins with extensions of dark body saddles above base, narrow whitish posterior margins (width variable in paratypes), remaining fin pale grey. Anal-fin base pale grey, posterior margin whitish, remainder of fin dark grey forming a broad, faint, subtriangular stripe. Pectoral fins with a strikingly distinct, narrow black anterior margin; fins darker dorsally than ventrally. Pelvic fins and claspers pale grey, naked skin along dorsal surface of clasper and near cloaca white. Head distinctly paler ventrally than dorsally, cheek mostly pale; roof of mouth dark grey to black, floor and jaws whitish.

Size. To at least 455 mm TL (biggest female); males maturing at about 380 mm but claspers may not be fully developed until 390 mm or so.

Distribution. Known from the marginal slopes off southern New Caledonia, south of the Loyalty Islands Ridge and north of the Norfolk Ridge in 620–830 m depth and off Espiritu Santo Island ( Vanuatu) in 262–352 m depth.

Etymology. From the Greek “ Priapos ”, God of reproduction in reference to the long claspers.

TABLE 2. Ratios of selected measurements of Galeus priapus sp. nov. and G. gracilis .

Remarks. This species is almost identical in general appearance and colour to G. gracilis . Comparisons of morphometric data from the type series of G. gracilis with those of P. priapus showed the following differences: the caudal-fin of P. priapus is longer (length of ventral caudal lobe 22 % versus 20 %); the anal fin is smaller (length 9.6–12.0% versus 12.4–13.8% TL; posterior anal-fin margin 4.6–5.9% versus 6.4–7.3% TL, 1.4–1.8 versus 1.1–1.2 in anterior margin of second dorsal fin; the pelvic-anal space is greater (10.0–11.7 % versus 8.0–10.3 %) and the prepectoral length is slightly shorter (17.8–19.4 versus 19.2–21.5% TL). The denticles on the upper caudal crest of P. priapus are less distinct anteriorly, originate more posteriorly, and are represented in more rows (mainly in 2–3 central rows anteriorly versus mainly 1). Also, the dorsal fins are mostly dark (rather than being mostly pale distally) and there are more vertebrae (precaudal centra 81–86 versus 74–78). Major differences exist in clasper structure: the claspers are extremely long (outer length 9.2–11.2 versus 5.2–7.3% TL in G. gracilis ( Compagno and Stevens, 1993, give 10.3–10.8% in the diagnosis of G. gracilis but from their data this appears to be based on the inner measurement) and more slender in adult males (7.2–8.7 versus 3.0–4.9 times base width); the distal tips extending almost to the anal origin or beyond (rather than well short); the clasper lacks spiny denticles at its tip (some present on G. gracilis ); the exorhipidion is much more elongate (up to 4 times spiracle length versus about 2.5 times); and the anterior inner margin of the pelvic fin is free from the clasper (rather than connected).

Figures

FIGURE 2. Galeus priapus sp. nov., holotype adult male 391 mm TL (MNHN 1997 - 3534).

FIGURE 3. Ventral view of head of Galeus priapus sp. nov., holotype adult male 391 mm TL (MNHN 1997 - 3534).