Belongs within: Carcharhiniformes.
Scyliorhinus is a genus of catsharks with the second dorsal fin much smaller than the first, and labial furrows present on the lower jaw only (Compagno 1984).
Characters (from Compagno 1984): Body not tadpole-shaped, moderately stout to slender and cylindrical or spindle-shaped, tapering considerably to caudal fin; body firm and thick skinned, with well-calcified dermal denticles; stomach not inflatable; tail moderately long, length from vent to lower caudal origin between 3/5 to 3/4 of snout-vent length. Head slightly to moderately depressed, narrowly rounded and not wedge-shaped in lateral view; head short, less than 1/5 of total length in adults; snout short, less than 3/4 of mouth width, thick, and slightly flattened, bluntly pointed in lateral view; snout not expanded laterally, rounded-parabolic in dorsoventral view; ampullal pores not greatly enlarged on snout; nostrils not enlarged to moderately enlarged, with incurrent and excurrent apertures only slightly open to exterior; anterior nasal flaps more or less triangular, sometimes slightly elongated, without a prominent barbel, well separated from each other and ending somewhat anterior to mouth but close together and reaching it in S. canicula; internarial space 0.3 to 0.8 times in nostril width; nasoral grooves usually absent except S. canicula in which broad grooves are present; eyes dorsolateral on head, broad subocular ridges present below eyes; mouth angular or broadly arched, moderately long, with lower symphysis somewhat behind upper so that upper teeth are well-exposed in ventral view (except S. canicula, in which upper teeth are obscured by lower jaw); labial furrows present along lower jaw only, these short to moderately long; vestigial uppers occasionally prsent; branchial region not greatly enlarged, distance from spiracles to fifth gill slits 1/2 to 2/5 head length; gill slits lateral on head. Two dorsal fins present, with the second considerably smaller than the first; origin of first dorsal varying from over last half of pelvic bases to over pelvic free rear tips; origin of second dorsal over last third of anal base to slightly behind anal insertion; pectoral fins large, their width about as great or considerably greater than mouth width. Inner margins of pelvic fins more or less fused over claspers in adult males, forming an 'apron'; claspers short, relatively thick, and distally pointed or rounded, extending less than half their lengths behind the pelvic fin tips; anal fin moderately large but not greatly elongated, subequal to pelvic and first dorsal fins but much larger than second dorsal, its base length 1.3 to 2.4 times the second dorsal base; origin of anal well behind pelvic bases, and insertion separated from lower caudal origin by a space varying from half as long to slightly longer than the anal base; caudal fin short and fairly broad, between 1/4 to 1/5 to less than 1/5 of total length in adults. No crests of denticles on the caudal margins; supraorbital crests present on cranium. Colour pattern extremely variable, ranging from simple dark saddles, reticulating dark bars, or large dark spots on a light background to combinations of light and dark spots and saddles.
<==Scyliorhinus Blainville 1816 (see below for synonymy) C84
|--*S. canicula (Linnaeus 1758) C84 (see below for synonymy)
|--S. besnardi Springer & Sadowsky 1970 [=S. retifer besnardi] C84
|--S. boa Goode & Bean 1896 [=S. retifer boa] C84
|--S. capensis (Smith in Müller & Henle 1838) [=Scyllium capense] C84
|--S. cervigoni Maurin & Bonnet 1970 C84
|--S. garmani (Fowler 1934) [=Halaelurus garmani] C84
|--S. haeckelii (Ribeiro 1907) [=Catulus haeckelii, S. retifer haeckelii; incl. S. fernandezi Weibezahn 1953] C84
|--S. hesperius Springer 1966 C84
|--S. meadi Springer 1966 [=S. retifer meadi] C84
|--S. retifer (Garman 1881) [=Scyllium retiferum] C84
|--S. stellaris (Linnaeus 1758) (see below for synonymy) C84
|--S. torazame (Tanaka 1908) [=Catulus torazame; incl. S. rudis Pietschmann 1908] C84
`--S. torrei Howell-Rivero 1936 [incl. Catulus boae Sanchez-Roig 1931] C84
Nomina nuda: Squalus (Scyliorhinus) breviculus Blainville 1816 C84
Squalus (Scyliorhinus) lambarda Blainville 1816 C84
Squalus (Scyliorhinus) myops Blainville 1816 C84
Squalus (Scyliorhinus) punctatus Blainville 1816 non Scylliorhinus punctatus Gilchrist 1914 C84
Squalus (Scyliorhinus) punctulatus Blainville 1816 C84
Squalus (Scyliorhinus) unicolor Blainville 1816 C84
Squalus (Scyliorhinus) variegatus Blainville 1816 C84
Scyliorhinus Blainville 1816 [=Scylliorhinus Blainville 1825, Scylliorhynchus (l. c.), Scylliorhynus (l. c.); incl. Alphascyllium Leigh-Sharpe 1926, Betascyllium Leigh-Sharpe 1926, Catulus Smith 1837 non Kniphof 1759, Scyllium Cuvier 1817] C84
*Scyliorhinus canicula (Linnaeus 1758) C84 [=Squalus canicula C84, Scyllium canicula S93; incl. Scyllium acutidens Vaillant 1888 C84, Scylliorhinus canicula var. albomaculata Pietschmann 1907 C84, Squalus catulus Linnaeus 1758 C84, Catulus duhamelii Garman 1913 C84, Sq. elegans Blainville 1825 C84, Scyllium spinacipellitum Vaillant 1888 C84]
Scyliorhinus stellaris (Linnaeus 1758) [=Squalus stellaris, Poroderma stellare; incl. Scyllium acanthonotum Filippi & Verany 1853] C84
*Type species of generic name indicated
REFERENCES
[C84] Compagno, L. J. V. 1984. FAO Species Catalogue vol. 4. Sharks of the World: An annotated and illustrated catalogue of shark species known to date. Part 2—Carcharhiniformes. United Nations Development Programme, Food and Agriculture Organization of the United Nations: Rome.
[S93] Schultze, H.-P. 1993. Patterns of diversity in the skulls of jawed fishes. In: Hanken, J., & B. K. Hall (eds) 1993. The Skull vol. 2. Patterns of Structural and Systematic Diversity pp. 189–254. The University of Chicago Press.
