Chalk See Cretaceous

Char Members of the genus Salvelinus, large troutlike fishes of northern Eurasia and North America. Salvelinus umbla (Linnaeus, 1758) is a form whose specific status has been questioned until recently, and most of the biological knowledge on char is thus derived from close relatives, notably the Brook and Arctic char, S.fontinalis and S. alpinus, respectively.

Char show up only once in CD's writings: the males of the char (S. umbla) are likewise at this season rather brighter in colour than the females23 (Descent II, p. 340; this season refers to the breeding-season and n. 23 refers to Thompson (1841), p. 440).

However, p. 440 in CD's source only states that "the male fish can at a glance be distinguished from the females either by colour or by the many characters which are comprised under 'form'". It is on other pages of that source that the brighter colours ofthe males are described. But should anyone care.?

Characins Members of a very speciose freshwater family, the Characidae, related to the Salmonidae, and ranging from Southern Texas to Argentina.

The most famous members of this family are the piranha, never mentioned by CD, notwithstanding their fearsome, if somewhat ill-deserved reputation (Pauly 1994b) and their occurrence in the upper Parana River, from which some of his fish *collection originates.

In Fish, the characins are classified as harmless cousins of the *trout, i.e. among the salmonids, though their pectoral fin causes painful pricks (Fish in Spirits,no. 180). They consist of six species, of which *Jenyns assigned five to the genus Tetragonopterus (pp. 123-8). For three of these, the only taxonomic updating required is their assignment to the genus Astyanax: A. abramis (Fig. 4A), A. scabripinnis (Fig. 4B), and A. taeniatus (Jenyns, 1842). The fourth species, T. rutilus, was found to be a synonym of A.fasciatus (Cuvier, 1819), while the fifth, T. interruptus, is now Cheirodon interruptus (Jenyns, 1842; Fig. 4C). The sixth species of characin in Fish is Oligosarcus hepsetus (Cuvier, 1829), which Jenyns originally assigned to the genus Hydrocyon (Fish, p. 128; Fish in Spirits, no. 661).

CD collected his characins from a running brook at Socego, province of *Rio de Janeiro (A. scabripinnis; Fish in Spirits, no. 288), near Rosario on the Parana River (A. abramis; A. fasciatus; Fish in Spirits, nos. 747, 748), and a lake near *Maldonado (C. interruptus; O. hepsetus). He reported on the live *colours of three species: Back bluish silvery, with a silver band on the side: a bluish black spot behind the gills. Fins pale orange; tail with a black central band (A. abramis); Back iridescent greenish brown: a silver bandon the side. Fins dirty orange: tail with a central black band: above and below the band bright red and orange (A. fasciatus; Fig. 4D); Bluish silvery (O. hepsetus).

Characins - especially those of the genus Astyanax- have often evolved into eyeless *cave-fishes (Kullander 1999), a topic of much interest to CD.

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