development ( oviparous species) . It has long been 

 known that orectolobid species are either oviparous 

 or ovoviviparous, but according to Bigelow and 

 Schroeder (19-18, p. 196), the scyliorhinids so far 

 as known are oviparous. Poll (1951) and Cadenat 

 (1959) subsequently reported the ovoviviparous 

 condition in one species of Galeus. Probably more 

 data will show that additional scyliorhinid species 

 are ovoviviparous. 



Began (1908) separated the scyliorhinids and 

 orectolobids as families and included Pseudotri- 

 akis in the Scyliorhinidae. He recognized only 

 two other genera in the family and included espe- 

 cially divergent species within the genus Scylwr- 

 hinus. White (1937), with the intention of 

 providing a vertical classification that would bet- 

 ter reflect phylogenetic lines, proposed two new 

 families, Aetelomycteridae and Halaeluridae, and 

 retained the family Catulidae ( = Scyliorhinidae) . 

 All genera of these three families of White except- 

 ing Prist iurus (= Galeus) were included in 

 Regan's genus Scyliorhinus. 



Bertin (1939) in a review of the classification 

 of the cartilaginous fishes placed the cat sharks 

 together with the orectolobids in the family 

 Scyliorhinidae, but placed PseudotriaJcis and 

 Pentanchus in monotypic families. Pseudotriakis 

 has a very long and low first dorsal fin with its 

 base entirely in advance of the pelvic fins, and this 

 is the primary morphological feature separating 

 it from the scyliorhinids which have short-based 

 dorsal fins (or single dorsal fin) located poste- 

 riorly, over or behind the pelvics. Pseudotriakis 

 is represented by two large species, one, Pseudo- 

 triahis microdon Brito Capello, reported from the 

 western Atlantic. Both species are larger than 

 any known cat sharks. Although PseudotriaJcis 

 is not treated here as a member of the family 

 Scyliorhinidae, its relegation to another family 

 may not be warranted. The distinctive arrange- 

 ment of tooth rows as diagonal bands character- 

 istic of PseudotriaJcis also occurs to a lesser degree 

 in Atelomycterus and has some similarities to the 

 tooth arrangement in Apristurus. Additional 

 similarities are found between PseudotriaJcis and 

 the small scyliorhinid shark from the coast of 

 Chile originally designated Scyllium canescens 

 Giinther, 1878. 



Pentanchus profundicollis Smith and Radcliffe, 

 1912, was described from a single Philippine speci- 



men as a notidanoid shark intermediate between 

 the Hexanchidae and Chlamydoselachidae but 

 with five gill openings instead of six or seven char- 

 acterizing the former. It is so close to the scylio- 

 rhinids of the genus Apristunis in general appear- 

 ance and details of gross structure, however, that 

 except for the presence of only one instead of two 

 dorsal fins, it would certainly fall within that 

 genus. Regan (1908) was of the opinion that 

 Pentanchus belonged in the family Scyliorhinidae 

 and suspected that the absence of one dorsal fin was 

 abnormal or accidental. Although additional 

 specimens are not yet known, the type USNM 70260 

 is an adult male in fair condition. This specimen, 

 disregarding the number of dorsal fins as a charac- 

 teristic, does not fit the description of any known 

 species of Apristurus. Furthermore, there is no 

 evidence from external examination or the appear- 

 ance in radiographs that the absence of a dorsal 

 fin (absent from the position occupied by the first 

 dorsal in Apristurus) is in any way a result of 

 accident or structural abnormality. Short sections 

 of the vertebral column from the trunk and caudal 

 portions of the type were missing when I examined 

 the type specimen but dissections had been care- 

 fully made somewhat off center and should not 

 have affected fin-base vestiges had these been pres- 

 ent. It appears to me that the separation of 

 Pentanchus and Apristurus (as in Bigelow and 

 Schroeder, 1948) is justified and that the two 

 genera are properly to be placed in the family 

 Scyliorhinidae. 



Distribution and Segregation 



About 58 species in 14 genera are known in the 

 family Scyliorhinidae. With the exception of the 

 Indian Ocean species, Atelomycterus marmoratus 

 (Bennett), cat sharks appear very rarely in warm 

 waters and inhabit shore waters only in the higher 

 latitudes or in comparatively cool-water areas. 

 The common rough-dog, Scyliarhmus caniculus 

 (Linnaeus), of Europe, which figures as a labora- 

 tory animal in much of the physiological and ex- 

 perimental work on sharks, is an example of a 

 species entering shallow waters. Cephaloscyllium 

 uter (Jordan and Gilbert) of the California coast 

 frequents relatively shallow water. In the west- 

 ern Atlantic one species is occasionally taken on 

 the continental shelf north of the Carolinas and 

 another species is said to frequent the shallow shore 

 waters in the vicinity of Cape Horn, but from the 



REVIEW OF WESTERN ATLANTIC CAT SHARKS 



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