Ctenacis species

3.4 | Comparison between Ctenacis species

Last and Vongpanich (2004) only provided comparisons of C. magnificum with Proscyllium habereri . As such, C. fehlmanni and C. magnificum have not been previously compared. Both these species have a complex color pattern which distinguishes them from other proscylliid sharks. The color pattern of C. magnificum (Figures 4 and 5) is far more complex than that of C. fehlmanni (Figure 3). The dorsal and lateral color pattern of C. magnificum consists of numerous dark reddish-brown spots and blotches of varying sizes (from size of spiracle to greater than eye), with some coalescing to form mitotic-like short bars (Figures 4 and 5). A series of saddles are evident in dorsal view, each consisting of a symmetrical arrangement of spots and blotches of different shapes. The strong color pattern extends onto all of the fins except the anal and ventral surfaces of the paired fins (although dorsal spots often evident through the skin in ventral view). In contrast, C. fehlmanni has more solid brown saddles, not made up of spots and blotches, with much less spotting on the fins than in C. magnificum .

Ctenacis magnificum also differs from C. fehlmanni in a combination of the following characters: anterior nasal flap edges closer to upper symphysis; anterior and posterior nasal flaps barely fringed (vs. fringed); first dorsal-fin origin just posterior to pectoral-fin free tips (vs. over pectoral-fin inner margins); pre-first dorsal length 31.0 – 32.6 vs. 33.7% TL; eye slightly smaller, length 3.6 – 3.9 vs. 4.3% TL, height 0.8 – 1.4 vs. 1.7% TL; mouth narrower, its width 6.9 – 7.3 vs. 9.3% TL; internarial width greater (2.4 – 2.6 vs. 3.5% TL) and nostrils smaller (2.6 – 2.9 vs. 3.3% TL); dorsal fins slightly lower (first dorsal-fin height 5.9 – 6.4 vs. 7.2% TL; second dorsal-fin height 5.0 – 5.5 vs. 6.3% TL); dorsal fins closer together (interdorsal space 19.3 – 21.0 vs. 17.8% TL); caudal peduncle slightly longer (anal-caudal space 7.8 – 9.4 vs. 6.5% TL); slightly less tooth files (upper jaw with 80 vs. 86 files).