Apristurus laurussoni (Saemundsson), 1922 



Figures 24, 25, and 27 ; tables 1, 7, and 8. 



Saemundsson's only specimen, the type of Scyl- 

 lium laurussonii, was a 673-mm. female. This 

 specimen, which is in excellent condition, was ex- 

 amined through the courtesy of the Natural His- 

 tory Museum, Reykjavik, as a loan. It differs from 

 the type specimen Goode and Bean of Scyllim-hinus 

 profundorum, 1896, with respect to characters 

 given in the preceding key. 



The separation of the broadheaded A. laurus- 

 soni from the narrow-headed A. riven and the 

 separation of A. laurussoni from A. profundorum 

 on the basis of the pelvic shape (see fig. 25) or the 

 denticle distribution problem presents no difficul- 

 ty except perhaps in very small specimens. 



Figure 25. — Diagram to show shapes of pelvci tins : At 

 left, Apristurus profundorum ; at right, Apristurus la-u- 

 ru^soni. 



A. laurussoni differs from our specimens of A. 

 indicus in having the two dorsal fins of approxi- 

 mately equal size. In A. indicus the first dorsal 

 fin has about half the area of the second. Both 

 laurussoni and indicus in the material examined 

 are quite variable in number of tooth rows, num- 

 ber of vertebrae, and fin positions. 



The teeth of A. laurussoni are small and com- 

 paratively numerous in 34 + + 34/34+0 + 32 to 

 42 + + 41/53 + 0+43 rows. The two largest males 

 examined, 520 and 540 mm., are apparently im- 

 mature, but there is no indication of sexual dimor- 

 phism in teeth in comparison with a 580-mm. 

 female or the type, a 673-mm. female. Saemunds- 



son (1922) noted that the teeth of the type are in 

 22 rows on each side of the symphysis. My count 

 of the teeth of the type specimen is approximately 

 41 rows on each side. This difference is the result 

 of a different method of counting rows. The 

 alternate arrangement of teeth together with their 

 generally small size makes routine tooth counting 

 in Apristurus impractical. In many specimens the 

 diagonal rows are very prominent and seem to be 

 the logical ones to count. In our specimens if 

 diagonal rows were counted, the tooth formula 

 would be close to that given by Saemundsson. 



It may be helpful to subsequent workers with 

 the genus to note that Goode and Bean's type and 

 only specimen of profoundorum is an adult male 

 while their illustration (1896, pi. 5, fig. 16) ap- 

 pears to be a female. Saemundsson's text refer- 

 ences to illustrations on plate V (1922, pp. 173 

 and 200) for Pristiurus Jensenii and Scyllium 

 Laurussonii are reversed, and the illustration of 

 the lateral view of a shark in Bigelow and Schroe- 

 der (1948, fig. 38) captioned as the type of 

 profundorum may not represent that species since 

 the illustration shows either a female or a male 

 with claspers not showing, while the type is a male 

 with claspers extending past the tips of the pelvics. 



Exclusive of the type which was collected from 

 560-m. depth near Vestmanneyjar, off the south- 

 ern coast of Iceland, I have examined about 25 

 specimens that I refer to the species. These are 

 from the northern half of the Gulf of Mexico and 

 from the Atlantic coast of the United States from 

 latitude 40°40' N. (off Massachusetts) southward 

 to 38°41' N. (off Delaware). Specimens were 

 taken from depths of 760 to 1,460 meters. 



Genus Halaelurus Gill, 1861 



Type species — Seyllium biirgeri Miiller and Henle, 1841, 

 by original designation. 



The group of scyliorhinid sharks usually as- 

 sembled in the genus Halaelurus seems to include 

 leftovers and poorly known species. It is in 

 special need of nomenclatural revision. Changes 

 can best be made in a general revision of the 

 world's scyliorhinid genera, which will require 

 more extensive collections than are available now. 



The American representatives of Halaelurus 

 have long and strong labial grooves along both up- 

 per and lower jaws and thus differ from American 

 species of the genus Scyliorhinus which have weak 

 and short labial folds only on the lower jaw. The 



REVIEW OF WESTERN ATLANTIC CAT SHARKS 



615 



