Stephanids are difficult to work with, mainly because of their highly uniform morphology. It is so extreme that some authors were inclined to propose a single "all-emcopassing" genus for the whole family (e.g. Ceballos, 1926). It is obvious, however, that extreme morphological similarity does not mean that discrete, monophyletic groups do not occur. It means only that they are more difficult to decipher. The South American genus Hemistephanus for example, is clearly monophyletic, as is the Indo-Australian Parastephanellus (Aguiar, in preparation), but they are very similar morphologically, being often confounded with each other.
Stephanid species can be recognized mainly by variations on the cuticular microsculpturing, which varies immensely, being of difficult interpretation. The shape of the pronotum and of the female pygidium, and some biometric ratios are also useful, but not for all genera, and these characters almost always show significant differences between the sexes.
Intermediate forms can be found for many pairs of stephanid species, no matter how close they are. Consequently, an almost perfect morphological gradient will usually be noticed, making the recognition and/or charachterization of a stephanid species a very laborious deal.
Interespecific Reproduction
In fact, some specimens are such perfect intermediates that it is tempting to think of them as possible hybrids, thus raising questions on the probability of interespecific reproduction. The extremely generalized male and female genitalia, almost identical on the two ends of the family, is a "mechanical" support to this idea. However, I have neither experimental evidence of interspecific reproduction, nor information on how compatible stephanids are geneticaly.
In any case, this context makes obvious to me that the availability of consistent taxonomic works on the Stephanidae will depend, at first, on a careful and thorough analysis of as many specimens and as many types as possible, what is precisely what I am doing now.
This page last updated: November 2, 1997.