Explanation of Names
Xestocephalus Van Duzee 1892
Numbers
>15 species in our area, ~120 spp. total
(1)
Xestocephalus brunneus Van Duzee, 1907: eastern U.S. and Canada
Xestocephalus coronatus Osborn & Ball, 1897: northeastern and midwestern U.S.
Xestocephalus fulvifrons Peters, 1933: TX
Xestocephalus fulvocapitatus Van Duzee, 1894: eastern U.S.; Canada
Xestocephalus lunatus Peters, 1933: FL
Xestocephalus nigrifrons Osborn, 1915: northeastern U.S. and Canada
Xestocephalus piceus Osborn, 1928: eastern U.S.
Xestocephalus provancheri Knull, 1944: eastern U.S.
Xestocephalus robustus Peters, 1933: FL
Xestocephalus similis Peters, 1933: eastern U.S. and Canada
Xestocephalus superbus (Provancher, 1890): eastern U.S. and Canada
Xestocephalus tessellatus Van Duzee, 1894: southeastern U.S.
Xestocephalus trimaculatus Peters, 1933: LA
Xestocephalus tucsoni Knull, 1944: AZ
Remarks
Many authors treat
Xestocephalus brunneus,
X. fulvifrons,
X. fulvocapitatus,
X. lunatus,
X. nigrifrons,
X. piceus,
X. provancheri,
X. pulicarius,
X. robustus,
X. similis,
X. superbus, and
X. trimaculatus as junior synonyms of the Argentinian species
Xestocephalus desertorum. Cwikla (1984)
(2) treated these species as the same due to the male genitalia of the species being practically identical in addition to the concept that the morphologies of these described species intergrade throughout their range and are indistinct. However, molecular analysis supports that most of these species are distinctive and we have seen that the external morphologies of many of these species are quite distinctive. It is possible that the intergradation observed by Cwikla is evidence of additional undescribed species as it is already clear that there are undescribed members of the genus in the eastern U.S. Because of this, we reject the most commonly used taxonomy for this genus.
Some spp. said to be
myrmecophiles, but some sources dispute this, at least for particular species
(Rakitov 2000)
There are at least four species endemic to Puerto Rico.