Chilomycterus, Brisout de Barneville in Brisout de Barneville, 1846

Leis, Jeffrey M., 2006, Nomenclature and distribution of the species of the porcupinefish family Diodontidae (Pisces, Teleostei), Memoirs of Museum Victoria 63 (1), pp. 77-90 : 82-83

“Atlantic Chilomycterus ”

Lyosphaera Evermann and Kendall, 1898: 131 (type species Lyospharea globosa Evermann and Kendall, possibly = Diodon schoepfii Walbaum, 1792 )

Atinga Le Danois, 1954: 2356 . (type species Diodon atringa

Linnaeus – see Eschmeyer, 2005, and below).

Diagnosis. All spines fixed; all spines with 3 bases; 9 C rays; 19–20 vertebrae; tentacles present on lower jaw and usually over eye; nostril in adult a short tube with 2 openings; no spines wholly on dorsal surface of caudal peduncle; no fins spotted (except in large C. antennatus ); large blotches present on dorsal surface. Some additional osteological characters are given by Tyler (1980, ref. 4477). At least 2 of the species of this group share the “ Lyosphaera ” larval stage ( antennatus and the type species of Lyosphaera ), and others may do the same.

Although the genus Lyosphaera Evermann and Kendall (1898, ref. 1281) is available as a generic name for this group, I recommend against its use until a cladistic analysis of the “Atlantic Chilomycterus ” species and their relationship to other diodontids is undertaken. Lyosphaera has never been used in this way, and the identity of the type species is unclear (although most likely to be schoepfii based on distribution). The species upon which Atinga Le Danois (1954, ref. 6451) is based is unclear. The type species, D. atringa Linnaeus (1758, ref. 2787), is not identifiable (see above under C. reticulatus ). It is clear that Le Danoisʼ (1954, ref. 6451; 1959, ref. 12003; 1962, 21440) concept of atinga included a species of the “Atlantic Chilomycterus ” group, although which species is unclear as her illustrations of Atinga atinga atinga in the 1954 paper are of C. antillarum (identified as male) and C. spinosus mauretanicus (identified as female). In view of this confusion about the identity of the type species, use of Atinga Le Danois (1954: ref. 6451) is not recommended. It has been little used since its description.

The “Atlantic Chilomycterus ” is a group of similar species previously recognized in various ways by Günther (1870, ref. 1995), Le Danois (1959, ref. 12003) and Tyler (1980, ref. 4477). See above regarding the generic status of these species. Chilomycterus antennatus is the only member of this group that I can separate on morphological grounds; principally, the development of the fleshy tentacles over the eye. It also has a colour pattern that differs more from the other species of the “Atlantic Chilomycterus ” group than they do from each other. The other four taxa differ only in colour, and have largely nonoverlapping distributions. In all but the case of the very similar forms, C. spinosus (Linnaeus, 1758, ref. 2787) and C. mauretanicus (Le Danois, 1954, ref. 6451), the distributions do at least seem to come into contact. In contrast, the latter two taxa occur only on opposite sides of the Atlantic and they have only very minor differences in colouration. Hence, I treat these two as subspecies: Chilomycterus spinosis spinosus and Chilomycterus spinosus mauretanicus . In some cases, colour patterns do exhibit intermediacy. Chilomycterus schoepfii adults have a distinctive lined pigment pattern, but the youngest C. schoepfii have a colour pattern not unlike that of C. spinosus (dark background with lighter, diffuse spotting), and at intermediate sizes, the dark background may have shrunk to a mesh-like pattern with expanded lighter centres similar to that of C. antillarum . Similarly, in northern South America, a colour pattern with elements of both C. spinosus and C. antillarum is present. Examination of the genetics of these “Atlantic Chilomycterus ” species would be very interesting.