Cephalotes Species Groups

The following is based on de Andrade, M. L.; Baroni Urbani, C. 1999. Diversity and adaptation in the ant genus Cephalotes, past and present. Stuttgarter Beitrage zur Naturkunde Series B (Geolgie and Palaontologie). 271:1-889.

hamulus clade

 * Cephalotes argentiventris
 * Cephalotes auricomus
 * Cephalotes flavigaster
 * Cephalotes hamulus
 * Cephalotes resinae
 * Cephalotes taino
 * Cephalotes unimaculatus
 * Cephalotes vinosus

This clade corresponds to the former genus or subgenus Hypocryptocerus and contains all the less specialised species of the genus Cephalotes. It is characterised by only three synapomorphies: (1) the vertexal angles broad, round and with crenulate margin, (2) the outer face of tibiae with longitudinal, irregular rugae, a character shared homoplastically also with the far relative rohweri (a member of the phylogenetically distant wheeleri clade) and with some species of the sister genus Procryptocerus, and, (3) petiolar spines present but shorter than 1/3 of the petiolar length, a character re-appearing in a number of distantly related, more specialised Cephalotes species. We regard this as an additional demonstration of the inappropriateness of considering Hypocryptocerus as a valid genus. We shall name the species of this group as hamulus clade for uniformity with other, comparable, phyletic lines we recognize within Cephalotes. Since the name Hypocryptocerus already exists in the literature, there are, however, no serious reasons against the use of this name as a subgeneric name for those preferring this formal solution.

Practically, if one disposes of abundant Cephalotes nest series, he should be able to recognise the members of the hamulus clade at glance by their possibly unique possession of one very important plesiomorphy: the absence of soldiers and the monomorphism of the worker caste, a character state unknown in other Cephalotes (though it may be present in the poorly known species Cephalotes placidus and Cephalotes oculatus in the atratus clade), but which is the rule among the species of the sister genus Procryptocerus.

Within the hamulus clade we recognise eight valid species and there is a possible, insufficiently known, ninth species. All these species are presumably endemic on the Island of Hispaniola and two of them are known only from copal samples of probable historical age. One could expect to encounter them again in the Recent fauna of the island.

A circumstance apparently contrasting with the antiquity of the clade is that its members are very similar each other and are likely to be the product of relatively young speciation events, a hypothesis supported also by palaeogeographic evidence. The main diagnostic characters among them appear to be confined to integumental sculpture, pilosity and coloration. As a result of this situation, the internal phylogeny of the clade is far from being properly understood and, due to our incapacity to detect sufficient, plausible synapomorphies, the internal phylogeny of this clade should be considered as tentative.

atratus clade

 * Cephalotes alfaroi
 * Cephalotes atratus
 * Cephalotes marginatus
 * Cephalotes oculatus
 * Cephalotes opacus
 * Cephalotes placidus
 * Cephalotes serraticeps