Classification, natural history, and evolution of the Epiphloeinae (Coleoptera : Cleridae). Part II. The genera Chaetophloeus opitz and Plocamocera spinola
- ISSN: 00030090
- DOI: 10.1206/0003-0090(2004)280<0001
This study deals with the sister genera Chaetophloeus, new genus and Plocamocera Spinola of the checkered beetle subfamily Epiphloeinae. Chaetophloeus is monotypic and is described on the basis of C. hispidus, new species. Plocamocera is revised to include 35 species as follows: P. castanea, new species; P. pupula, new species; P. jayhawkalis, new species; P. confrater Kuwert; P. procera, new species; P. aliguantula, new species; P. minima, new species; P. manausensis, new species; P. coactilis, new species; P. sericella Spinola; P. auratilis, new species; P. argentea, new species; P. lucis, new species; P. sesquipedalis, new species; P. salasis, new species; P. iota, new species; P. prolixa, new species; P. quadrula, new species; P. baria, new species; P. aura, new species; P. buenavista, new species; P. taruma, new species; P. aspera, new species; P. paris, new species; P. bispina, new species; P. onorei, new species; P. carnegei, new species; P. santa, new species; P. sericellopsis, new species; P. insula, new species; P. ambra, new species; P. similis, new species; P. bolivari, new species; and P. selva, new species. A neotype is selected for P. sericella Spinola. Lectotypes are designated for P. confrater Kuwert and P. byssinus Erichson (junior synonym of P. sericella Spinola). Five new synonymies are recognized, they are P. confrater var similis Kuwert (junior synonym of P. confrater Kuwert), P. confrater var. sericelloides Kuwert (junior synonym of P. confrater Kuwert), P. impressicollis Pic (junior synonym of P. confrater Kuwert), Epiphloeus byssinus Erichson (junior synonym of P. sericella Spinola), and P. latefasciata Pic (junior synonym of P. sericella Spinola). Plocamocerans are diurnal, but are considerably active at night, highly cryptic on bark, when disturbed conduct flylike escape behavior, and are predators of lignicolous insects. The morphology of integumentary sensilla on the antenna, pronotum, and elytra are described, and SEM photographs of them is provided. Described for the first time are four types of antennal sensilla (one type of sensilla trichodea, two types of sensilla chaetica, and one type of sensilla basiconica), four pronotal trichobothria, and three types of pronotal sensilla trichodea, and on the elytra of Plocamocera confrater Kuwert eight trichobothria and two types of sensilla trichodea. It is postulated that filamentous sensilla trichodea on the antenna serve to perceive volatile tree trunk chemicals and/or aggregate pheromones of prey bark beetles. The study includes a review of trichobothrial function and distribution among insects. Morphological analysis is extended to include structure of the internal reproductive organs of some plocamoceran species. Also included are a discourse on species-level discontinuities; discussion of the specimen-study methods; methods for phylogenetic analysis; a treatise of evolutionary relationships based on Hennigian principles implemented in a data base analysis involving Farris's Hennig 86 which produced a computer-based phylogeny involving genera, species groups, and species; a list of specimen repositories (with e-mail addresses); key to species groups and species; table of character-state analysis; four color photographs; 20 SEM photographs; a total of 219 illustrations; 12 distribution maps; and one diagram of phylogeny that depicts a hypothesis of inter-and intrageneric evolutionary relationships. The 35 plocamoceran species are categorized into six species groups whose combined distribution extends from southern Mexico to southern Brazil. The members of the confrater and coactilis species groups are superficially very similar; their aedeagal structure and shape of antennomeres must be examined in detail for credible identifications at the species level. The sister group relationship between Chaetophloeus and Plocamocera is supported by the following four synapomorphies, they are pedicel very large, aedeagus lanceolate, male accessory glands reduced to two pairs, and metabasitarsomere one longer than metabasitarsomere two. Profuse distribution of bristlelike setae (chaetosomes) on the dorsum, forebody, and elytral disc and presence of moderately elongated sensilla trichodea on the antenna are autapomorphies for Chaetophloeus, whereas filamentous sensilla trichoidea on the antenna, boldly transverse pronotum, very robust metacoxa, very robust metafemora, presence of trichobothria on the epipleural margin, and sex dimorphism of abdominal color are synapomorphic character states that establish the monophyly of Plocamocera and define its ancestral basic plan. It is postulated that South America was the ancestral environs of Chaetophloeus and Plocamocera and that there were three independent northward extensions of major plocamoceran lineages into Central America.