Archocentrus Gill

Juan J. Schmitter-Soto, 2007, A systematic revision of the genus Archocentrus (Perciformes: Cichlidae), with the description of two new genera and six new species., Zootaxa 1603, pp. 1-78 : 4-6

[[ Genus Archocentrus Gill ]]

The cichlid fish genus Archocentrus was originally proposed as a subgenus of Heros Heckel by Gill (in Gill & Bransford 1877), and later treated as an informal “section” of Cichlasoma Swainson in Regan’s (1905) revision of the genus. The generic status of Cichlasoma sensu Regan (1905), encompassing more than 100 species, has been in a state of uncertainty since Kullander’s (1983) restriction of Cichlasoma sensu stricto to 12 South American species. Of the many remaining groups of species formerly referred to Cichlasoma , those referred to Archocentrus have been among the strongest candidates for recognition as a monophyletic group (e.g. Miller 1993, Miller et al. 2005). Species assigned to Archocentrus are major components of the neotropical Central American ichthyofauna from southern Mexico to Panama, occurring across all the ichthyolimnological provinces of Bussing (1976), but the monophyly of the genus has not been explicitly demonstrated and its species composition has been far from clear.

Since a comprehensive analysis of Cichlasoma sensu lato appeared unlikely, Kullander (1996) advocated the provisional use of available generic names, a procedure that some workers had already adopted. Kullander himself (1983), Stiassny (1991), and Miller (1993) had earlier recommended that the use of ‘ Cichlasoma ’- with the quotation marks indicating its informality - would prevent further confusion. Because the systematics of all species previously referred to Cichlasoma had not yet been completely resolved, Nelson et al. (2004: 151-153) chose the conservative approach and tentatively referred all species to Cichlasoma in the most recent checklist of fishes for the United States, Canada, and Mexico.

Several species have been assigned to Archocentrus more or less consistently in the literature (Table 1). Allgayer (2001) restricted Archocentrus to include the two largest species ( Ar. centrarchus and Ar. spinosissimus ), and referred six others to a new genus, Cryptoheros (type species, Cr. spilurus ), which also included the new species Cr. altoflavus . Other species that have sometimes been assigned to Archocentrus (Table 1) include: Heros octofasciatus , though more frequently placed in incertae sedis; H. citrinellus , albeit demonstrated by Roe et al. (1997) to be an Amphilophus ; H. multispinosus , generally considered in the monotypic genus Herotilapia ; and Neetroplus panamensis , variously included in Archocentrus (in Kullander 2003), Theraps (in Eschmeyer 2001), or Hypsophrys (in Bussing 1998).

To complicate things further, variation within some Archocentrus species has not been evaluated before. Hubbs (1936) observed tantalizing meristic and morphometric differences among populations of Cichlasoma octofasciatum , but he chose not to describe any subspecies because, in his material, geographic differences were confounded with differences in body size.

Considering the potential for undetected biodiversity within presently recognized species, especially those more widely distributed, lectotypes are designated in the present work: Amatitlania nigrofasciata , Archocentrus spinosissimus , Cryptoheros septemfasciatus , Cr. spilurus , and Rocio octofasciata . Cichlasoma immaculatum is shown to be a synonym of Cryptoheros spilurus and not of Archocentrus spinosissimus , although it was first described as a “variety” of the latter.

The present revision treats all nominal species ever assigned to the genus Archocentrus , as well as species that have appeared in the same clade as (or as sister group to) Archocentrus centrarchus in relevant phylogenetic analyses ( Roe et al. 1997, Martin & Bermingham 1998, Farias et al. 2000). Six new species are described and a seventh is resurrected from synonymy. Archocentrus , Cryptoheros , and Hypsophrys are redefined, and two new genera ( Amatitlania and Rocio ) are diagnosed.

Genus-level decisions in this work are supported by a phylogeny (Schmitter-Soto, in press), published separately, which includes most character illustrations and analysis.