Squatina caillieti Walsh, Ebert & Compagno, 2011, sp. nov

Autor: Walsh, Jonathan H., Ebert, David A., Compagno, Leonard J. V.
Rok vydání: 2011
Předmět:
DOI: 10.5281/zenodo.6191153
Popis: Squatina caillieti sp. nov. (Figures 1, 2, Table 1) Holotype, CAS 226473, immature female, 328 mm total length, Taiwan Fisheries Research Institute Fishery Researcher 1 sta. FR 1 -PHI-02-95, 23 September 1995, 363��� 385 m, Philippines, Luzon, 13 ��08.98���09.84'N, 124 ��04.72���00.01'E, collected by L.J.V. Compagno and P.R. Last. Squatina formosa: Compagno et al., 2005 a, Sharks of the World, p 142, fig, pl. 18. Compagno et al., 2005 b, Checklist of Philippine Chondrichthyes, p 56. Diagnosis. A squatinid distinct from other western North Pacific squatinids based on the following characteristics: unfringed barbels with rod-like tips; upper lip arch semi-oval in shape, upper lip arch height (1.2), upper lip arch width (4.3); large papillae present on the inside posterior margin of the spiracles; a greater interspiracle space (8.9) than interorbital space (8.6); lacking midback row of thorny tubercles; large prominent ocelli not present on pectoral fins; pelvic fintips reaching the first dorsal origin, pelvic fin base short (12.9), pelvic inner margin very short (8.6) and short pelvic posterior margin (16.3); pelvic girdle width (27.9) more than 1.4 times greater than head length (18.7); dorsal fins angular, greater interdorsal space (7.4) than dorsal caudal space (6.4), subdorsal saddles present; caudal fin lobed, very short upper postventral caudal margin (2.5). Description. Dorsal surface covered with interspersed denticles of moderate roughness; ventral surface comparatively smooth, except for narrow bands of denticles along anterior margins of both pectoral and pelvic fins. Head rounded, length slightly less than 0.2 times total length, with a maximum width occurring anterior of gill openings. Moderate tubercles interspersed above mouth and eye crests, smooth oval patch above midpoint of mouth in between eyes. Eyes are almond-shaped, closely set, with an interorbital space of 8.6; eye-spiracle distance short (1.5). Spiracles are crescent shaped with pronounced papillae on interior along posterior margin. Interspiracle space (8.9) is slightly greater than interorbital space (8.6). Center of upper lip arch exposed at midpoint of upper jaw, exposure semi-oval in shape, extending dorsally approximately 0.6���0.7 of upper jaw space, upper lip height (1.2), and upper lip arch width (4.3). Labial furrows, roughly equal in length, extending from corners of mouth medially, with upper labial furrow partially covered with dermal folds. Distinct nasal flaps protruding from dermal folds above mouth, two barbels protruding from each flap; inner nasal barbel rod-like with small branch protruding ventrally near tip, inner basal portion contains little if any fringe; outer nasal barbel rod-like. Nostrils large, protruding slightly, and tear-shaped. Dermal folds along exterior of head, one small lobe present at corners of mouth extending ventrally. Mouth length about 0.3 times as long as mouth width. Dentition consisting of small, daggerlike teeth, conical without cusplets on a broad base, in 2 orderly longitudinal rows on upper jaw, 3 rows on bottom jaw, no teeth at symphysis, teeth by row 10 ��� 10. 9 ��� 9 Pectoral fins large and broadly rounded, originating just behind gills. Anterior margin of pectoral fin mostly straight and about three quarters as long as pectoral length, extending to a lateral apex. Angle of lateral apex is slightly more obtuse than 120 ��. Margin from lateral apex to posterior-most lobe slightly concave. Posterior lobe broadly rounded. Pectoral inner margin is slightly less than one half of pectoral length, convex, and with a small lobe near pectoral base. Overall pelvic fin shape is somewhat triangular with rounded fintips. Pelvic fins originating anterior to pectoral fin free rear tips. Pelvic fin length approximately three quarters as long as pectoral fin length. Pelvic fin base is approximately equal to pectoral fin base. Anterior margin slightly curvilinear, extending at roughly a 45 �� angle from trunk to rounded apex lateral of body, anterior margin 0.4 times as long as pelvic fin length. Pelvic girdle span (27.9) between pelvic fin apices moderately broad, about 1.5 times head length. Posterior margin of pelvic fin straight to posterior free tip approximately 0.7 times fin length. Pelvic inner margin is straight and short, approximately 0.4 times as long as pectoral fin length. Pelvic fin insertion furrows on ventral extend in a narrow ellipse to anterior apogee of vent, vent is within ellipse. One pelvic fin tip extends to first dorsal origin, the other does not. Dorsal fins slightly angular, second dorsal fin slightly smaller than first dorsal fin, with denticles covering the whole of fins. Interdorsal space is about 1.1 times longer than dorsal caudal space. Anterior margin of both dorsal fins straight, nearly equidistant. Dorsal bases equal, first dorsal base (4.6), second dorsal base (4.6). Apex of first and second dorsal fins both lobed. Posterior margins straight, about 0.5���0.6 times as long as anterior margins. Inner margin of dorsal fins straight, approximately 0.4 times as long as anterior margins. Caudal peduncle compressed dorso-ventrally with lateral longitudinal ridges, tapering posteriorly. Caudal fin lobe-like, markedly at dorsal apex, dorsal margin broadly rounded, about 0.8 times as long as preventral caudal fin margin. Subterminal caudal fin margin is approximately 1.4 times longer than caudal upper post ventral margin. Caudal lower postventral margin is slightly convex, approximately 1.5 times longer than caudal upper post ventral margin. Total vertebrae 137; total precaudal vertebrae 111, monospondylous vertebrae 51, diplospondylous vertebrae 60, caudal vertebrae 26. Spiral valve count: 7. Coloration. Dorsal surface of holotype was greenish in color throughout with numerous brown spots, outlined in white; pelvic fins with white margins; black subdorsal saddles were also present. Upon preservation, the specimen faded to a deep uniform brown with numerous white spots; subdorsal saddles were lost with preservation as was the white edging on the pelvic fins; ventral side is uniformly white. Distribution. Holotype and only known specimen caught off Luzon (13 ��08.98���09.84'N, 124 ��04.72���00.01'E), Philippine Islands (Figure 3) at a depth of 363���385 m in a trawl. Etymology. The new species is named in honor of Dr. Gregor Cailliet for his outstanding contributions in the field of ichthyology, especially in the area of chondrichthyan age and growth. Pronunciation of caillieti: [kai- yā - i]. Remarks. Although similar to other western North Pacific (WNP) squatinids, there are several characters that distinguish S. caillieti from other regional squatinids. In our previous work on WNP squatinids (Walsh & Ebert 2007), we showed that a major character in identification of this group was the pelvic fin tips in relation to the first dorsal fin origin. In S. caillieti the fin tips reach the dorsal origin, negating the possibility that the specimen is either S. japonica or S. tergocellatoides. In addition, the specimen lacks midback spines (S. japonica), ocelli or fringed barbels (S. tergocellatoides), has a lower spiral count than other WNP squatinids, and differs dramatically from both in coloration. Squatina caillieti is also distinct from the recently described Indonesian Squatina legnota (Last & White 2008). The pelvic fin tips of S. legnota do not reach the first dorsal fin origin, which is not the case in S. caillieti. Also, S. legnota has a greater dorsal-caudal space (DCS) than inter-dorsal space (IDS), which is the convers condition found in S. caillieti. Additionally, S. caillieti differs slightly from S. legnota as it is a lighter brown color and has more noticeable ocelli after preservation when the mucous layer is not present. Unfortunately, no photos of fresh S. legnota specimens were available for comparison. Squatina caillieti more closely resembles the other two known WNP species, S. formosa and S. nebulosa, but several morphometrics differences are present by which these three species can be distinguished from each other. The pelvic fin measurements for S. caillieti are smaller at the posterior margin (P 2 P) than S. formosa, and smaller at the inner margin (P 2 I) and base (P 2 B) than both S. formosa and S. nebulosa. Squatina caillieti also has a markedly smaller upper postventral caudal margin than both S. formosa and S. nebulosa. In addition, Squatina caillieti also has a greater interspiracle distance (ISP) than interorbital distance (INO), a character unique among all specimens examined. Among the other two species, S. formosa INO is equal to ISP, and S. nebulosa, INO is greater than ISP (Figure 4). Squatina caillieti is also the only known WNP squatinid to have a greater interdorsal space (IDS) than dorsal-caudal space (DCS) (Figure 5). Squatina caillieti also appears to be the only WNP squatinid with large papillae in the inner posterior margin of the spiracles, but more specimens should be examined to validate this character. Finally, although possessing similar vertebral counts to S. formosa and S. nebulosa, S. caillieti has less caudal vertebrae and a lower spiral valve count than those species (Table 2). The observed characteristics distinguishing S. caillieti from other western Pacific squatinids were consistent among all individuals of each species examined. Furthermore, individuals of each comparative species were compared between similar sized individuals reducing variation due to ontogenetic changes in size. Although additional specimens, particularly of S. caillieti would benefit character analysis, the study did benefit from comparison between the holotypes of S. formosa and S. nebulosa, the new species, and additional comparative specimens of each of these and other western Pacific squatinids. The genus Squatina is highly diverse in the WNP with at least five species now recognized (Figure 6). All five species based on the current knowledge of their distribution appear to be endemic to the WNP. At the present time the only known capture of a S. caillieti is from off Luzon in the Philippines Islands. However, to the north in the waters surrounding Taiwan at least four other species are known to occur; S. formosa, S. japonica, S. nebulosa, and S. tergocellatoides (Walsh & Ebert, 2007). Interestingly, of the four species known to occur around Taiwanese waters two of them tend to be sympatric in more northerly, cooler waters north of Taiwan. Both S. japonica and S. nebulosa are known to occur from Taiwan northwards to the main Japanese island of Honshu, including the Sea of Japan, and as far north as Hokkaido, also they occur along the Chinese mainland into the Yellow Sea, and along the Korean Peninsula (Compagno et al., 2005 a). The poorly known S. tergocellatoides is known primarily from off Taiwan and Malaysia (Yano et al., 2005). It is likely that this species is wider ranging and may occur in the Philippines. The poorly known S. formosa at the present time has only been reported from Taiwan, but as identification of WNP squatinids improves its distribution will likely broaden. Finally, a sixth species, the recently described S. legnota, is known only from off Cilacap, Central Java, Indonesia, Bali, and Lombok in the western South Pacific (Last & White, 2008) and from discarded specimens from Bali and Lombock, but may be more wide-ranging once its distribution is better understood. With the addition of the new species we herein provide a revised and updated key to the WNP squatinids follows. S. caillieti sp. nov. S. formosa S. nebulosa Vertebral counts n = 1 n = 2 n = 4 Total 137 137���139 138���139 Pre-caudal 111 107���110 108 Monospondylous 51 48���52 49 Diplospondylous 60 58���59 59 Caudal 26 29���30 30���31 n = 1 n = 1 n = 1 Spiral Valve count 7 9 12
Published as part of Walsh, Jonathan H., Ebert, David A. & Compagno, Leonard J. V., 2011, Squatina caillieti sp. nov., a new species of angel shark (Chondrichthyes: Squatiniformes: Squatinidae) from the Philippine Islands, pp. 49-59 in Zootaxa 2759 on pages 50-58, DOI: 10.5281/zenodo.202748
{"references":["Compagno, L. J. V., Dando, M. & Fowler, S. (2005 a) Sharks of the world. Princeton University Press, Princeton and Oxford, 368 pp.","Compagno L. J. V., Last, P. R., Stevens, J. D. & Alava, MNR. (2005 b) Checklist of Philippine Chondrichthyes, CSIRO Marine Laboratories, Report 243, Hobart, Australia, 109 pp.","Walsh, J. H. & Ebert, D. A. (2007) A review of the systematics of western North Pacific angel sharks, genus Squatina, with redescriptions of Squatina formosa, S. japonica, and S. nebulosa (Chondrichthyes: Squatiniformes, Squatinidae). Zootaxa, 1551, 31 - 47.","Last, P. R. & White, W. T. (2008) Three new angel sharks (Chondrichthyes: Squatinidae) from the Indo-Australian region. Zootaxa, 1743,1 - 26.","Yano, K., Ahmad, A., Gambang, A. C., Idris, A. H., Solahuddin, A. R. & Aznan, Z. (2005) Sharks and rays of Malaysia and Brunei Darussalam. SEAFDEC-MFRDMD / SP / 12. Kuala Terengganu, 557 pp."]}
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