Scyliorhinus garmani ( Fowler, 1934 )

Soares, Karla D. A. & De, Marcelo R., 2019, The catshark genus Scyliorhinus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae): taxonomy, morphology and distribution, Zootaxa 4601 (1), pp. 1-147 : 65-68

Scyliorhinus garmani ( Fowler, 1934)

( Figs. 46–48 ; Tab. 10 )

Halaelurus garmani Fowler 1934: 235 , fig. 1 (original description, type locality: East Indies); Fowler, 1941: 49, fig. 1 (catalogue, Philippines); Herre, 1953: 11 (listed, Philippines).

Scyliorhinus garmani: Springer & Garrick, 1964: 86 (listed); Springer, 1979: 135 (taxonomic review); Compagno, 1984: 362 (FAO catalogue); Carpenter & Niem, 1998: 1205 (FAO catalogue, Western Central Pacific); Randall & Lim, 2000: 579 (listed, southern China Sea); Compagno, 1999: 480 (listed); Compagno et al., 2005: 249 –250, pl. 52 (compilation); Ebert et al., 2013a: 374, 380, pl. 51 (compilation); Weigmann, 2016: 43 (listed).

Holotype. USNM 43749 , female, 267.2 mm TL (“ East Indies ”, probably Philippines).

Diagnosis. Scyliorhinus garmani differs from all congeners by presenting a color pattern with dark brown spots, greater than the spiracles and scattered on body (vs. dark spots absent in S. hesperius , S. capensis , S. comoroensis , S. meadi , S. torazame , and S. torrei ; reticulate pattern in S. retifer ; spots predominantly smaller than spiracles in S. cabofriensis and S. canicula ; dark spots more frequent within saddles and subsaddles in S. boa , S. haeckelii and S. ugoi ); pelvic fins trapezoidal (vs. subtriangular in other species, except S. stellaris ); counts of monospondylous vertebrae 48 (vs. lower values in all other species, except S. meadi ). The following combination of characters, although less conspicuous, also helps distinguish this species: saddles inconspicuous (vs. saddles prominent in S. capensis , S. comoroensis , S. haeckelii , S. hesperius , S. meadi , S. torazame , and S. ugoi ); light spots absent (vs. present in all other species, except S. cervigoni ); anterior nasal flaps reaching the upper lip (vs. not reaching in other species, except S. canicula , S. cervigoni , S. comoroensis , S. duhamelii , and S. stellaris ); interdorsal space 0.7 times the anal base length (vs. greater than the anal base in S. boa , S. cabofriensis , S. haeckelii , S. hesperius , S. meadi , S. retifer , S. torrei , and S. ugoi ).

Description. Morphometric and meristic data of the holotype (and only known specimen) are given in Table 10 .

Body slender and cylindrical, tapering considerably posterior to cloaca ( Fig. 46 ). Prepectoral length 0.4 times the prepelvic length. Trunk shorter than tail; snout-vent length 0.8 times vent-caudal length. Pectoral-pelvic space 1.8 times the pelvic-anal space. Interdorsal space 1.5 times the dorsal-caudal space ( Tab. 10 ). No interdorsal, postdorsal or postanal ridges; lateral crest on caudal peduncle absent.

Head moderately broad and depressed; head length 1.7 times head width ( Figs. 46 , 47 ). Snout relatively short, preoral length 0.6 times mouth width and 0.8 times smaller than preorbital length. Prenasal length 0.7 times internarial space; preorbital length 0.8 times interorbital space.

Eye large and slitlike, eye length 2 times its height and 0.2 times smaller than head length ( Figs. 46 , 47 ). Eye dorsolateral on head, with lower edge medial to horizontal head rim in dorsal view; subocular ridge strong. Nictitating lower eyelid of rudimentary type, with shallow subocular pouch and secondary lower eyelid free from upper eyelid. Spiracle close behind but well separated from eyes, dorsolaterally on head and somewhat lower than level of eye notch. Spiracle diameter goes 4.3 times in eye length and 10 times in interorbital width.

First two gill openings about equally wide; first one twice as long as fifth. All gill openings slightly concave and not elevated on dorsolateral surface of head; gill filaments not visible externally.

Nostril with broad incurrent aperture, without nasoral groove or nasal barbel, and small and oval excurrent aperture. Anterior nasal flap large, triangular, and covering posterior nasal flap excurrent aperture and upper lip ( Fig. 47A ). Mesonarial ridge distinct and exceeding the posterior border of the anterior nasal flap, overlapping upper lip and jaw. Posterior nasal flap rectangular, situated on the posterior border of the anterior nasal flap. Mesonarial superior and inferior flaps conical and corresponding to 1/4 of the anterior nasal flap. Internarial space 0.6 times smaller than interorbital space.

Mouth arched, moderately wide and short, its length goes 1.7 times in mouth width ( Fig. 47 ). Lower labial furrow short and narrow, 3.4 times smaller than mouth width. Dorsal labial cartilage 1.3 times the ventral cartilage; anterior tip of dorsal labial cartilage reaching the orbital process of the palatoquadrate. Tongue flat and rounded, light-colored, with oral papillae hardly detectable.

Monognathic heterodonty gradual well developed; anterior teeth abruptly larger than the parasymphysial ones and lateral teeth smaller distally, with smaller and thicker principal cusps. Tooth counts 22–24/ 22–1–22. Upper teeth with slightly higher principal cusps than lower ones, and striae longer and stouter. Parasymphysial and anterior teeth similar in shape and principal cusp straight; one cusplet on each side of the principal cusp. Lateral teeth with principal cusp slightly oblique and one cusplet at each side. Commissural teeth not examined.

Lateral trunk denticles with flat, elongated teardrop-shaped crowns (examination under stereomicroscope). Crown with a strong medial ridge extending its entire length onto long principal cusp and flanked by lateral ridges less prominent. Row of denticles on each side on the body extending from the level of pectoral fin origin until the first dorsal fin origin; 25 denticles slightly larger than the adjacent ones, smooth and with no pigmentation.

Pectoral fin base 0.7 times mouth width ( Fig. 47A ). Pectoral anterior margin 2.4 times its base and 2 times the posterior margin. Pectoral fin skeleton not examined.

Pelvic fin subrectangular ( Fig. 47D ); pelvic anterior margin 1.8 times the posterior margin and 1.1 times the pelvic base. Posterior margin perpendicular to the anteroposterior axis of the body.

First dorsal fin subrectangular, with nearly straight anterior margin and rounded apex; angular free rear tip with the same inclination as the anterior margin ( Fig. 46 ). First dorsal fin origin opposite to the 1/4 posterior of pelvic fin base. First dorsal fin insertion opposite to half-length of pelvic fin inner margins. Anterior margin 1.6 times first dorsal fin base; first dorsal fin height 0.8 times its base.

Second dorsal fin smaller than the first and triangular ( Fig. 46 ). Second dorsal fin origin slightly opposite to the half-length of anal fin base. Anterior margin 1.5 times base of second dorsal fin; second dorsal base 1.8 times its height and 1.2 times the dorsal-caudal distance. First dorsal fin 1.2 times larger than the second dorsal fin.

Anal fin low, apically narrow, not falcate and similar to second dorsal fin; anal fin base 1.7 times the second dorsal fin base ( Fig. 46 ). Anal fin anterior margin nearly straight, apex narrowly rounded, free rear tip acutely pointed, and inner margin straight. Anal fin base 1.4 times the interdorsal distance and 2 times the dorsal-caudal distance. Anal anterior margin 2.1 times the posterior margin; anal fin height 0.3 times its base.

Caudal fin narrow-lobed and asymmetrical ( Fig. 46 ). Dorsal caudal lobe 1.7 times larger than preventral lobe; subterminal caudal margin as long as the terminal margin. Caudal crest of enlarged denticles absent on caudal fin margins. Neurocranium examined through radiographs; corresponding to approximately 10% TL.

Coloration in alcohol. Body light beige with nine saddles that are only slightly darker than the background color ( Fig. 46 ). Dark brown spots larger than the spiracle, scattered around the dorsolateral surfaces and fins, including the anal fin. Belly and ventral surface of paired fins without spots, cream in color.

Distribution. The type locality mentioned by Fowler (1934) is “East Indies”. The holotype was captured by RV Albatross during a survey around the Philippines between 1907 and 1910, and probably close to this country, in the Indo-Western Pacific ( Compagno 1984; Compagno et al. 2005; Ebert et al. 2013a) ( Fig. 48 ).

Etymology. The specific name ‘garmani’ was dedicated to Samuel Walton Garman (1843–1927), renowned herpetologist and ichthyologist of the Museum of Comparative Zoology of Harvard University.

Remarks. This species was described by Fowler (1934) and originally allocated in Halaelurus , subgenus Halaelurus . The author suggested there is a similarity between S. garmani and H. analis (= Asymbolus analis ), but pointed out that the first species differs in color pattern by having large and prominent dark spots and saddles on the body.

Fowler (1941) retained the same classification and presented a definition for the genus Halaelurus , but contradicted the characters present in the original description of S. garmani . These characters were the presence of moderate or short labial furrows in both jaws and anterior nasal flaps not reaching the mouth. According to the description of S. garmani , anterior nasal flaps not only reach the mouth but also overlap the upper lip, and only the lower labial furrow is present, although the upper furrow was illustrated ( Fowler, 1941; p. 49, fig. 1). On the other hand, S. garmani could easily have been allocated to Scyliorhinus based on the description provided by Fowler (1941).

Bigelow & Schroeder (1948) emphasized the relevance of labial furrows in definitions of catshark genera. Considering the taxonomic key provided by these authors, however, S. garmani would have been allocated in the genus Scyliorhinus and not Halaelurus . Springer & Garrick (1964) presented a table with counts of vertebrae for catsharks and placed garmani in Scyliorhinus for the first time, but no explanation was provided.

Springer (1979) examined the holotype of S. garmani and pointed out that, besides having labial furrows typical for species of Scyliorhinus , the species presents the supraorbital crest on the neurocranium (absent in Halaelurus ). Therefore, the species was confirmed belonging in Scyliorhinus ; subsequent authors followed this arrangement ( Compagno 1984; Compagno et al. 2005; Ebert et al. 2013a; Weigmann 2016).

Figures

FIGURE 46. Holotype of Scyliorhinus garmani (Fowler, 1934), USNM 43749, female, 267.2 mm TL ("East Indies", probably Philippines). A, dorsal view; B, lateral view. Scale bar = 20 mm.

FIGURE 47. Scyliorhinus garmani, USNM 43749, female, 267.2 mm TL ("East Indies", probably Philippines). A, ventral view of head and pectoral fins; B, lateral view of head; C, dorsal view of head; D, detail of pelvic fins. Scale bar = 10 mm.

FIGURE 48. Map showing the geographic distribution of Scyliorhinus garmani based on material examined in this study. Black star indicates the type locality.