Phylogenetic revision of the genus Arenivaga (Rehn) (Blattodea: Corydiidae), with descriptions of new species, a key to the males, and an investigation of its ecological niche.

摘要

The cockroach genus Arenivaga is revised. Forty-eight Arenivaga species are recognized with nine previously known species and 39 described as new including the following: A. pagana sp. n., A. grandiscanyonensis sp. n., A. haringtoni sp. n., A. hopkinsorum sp. n., A. umbratilis sp. n., A. tenax sp. n., A. impensa sp. n., A. trypheros sp. n., A. darwini sp. n., A. nalepae sp. n., A. sequoia sp. n., A. mckittrickae sp. n., A. gaiophanes sp. n., A. belli sp. n., A. estelleae sp. n., A. delicata sp. n., A. mortisvallisensis sp. n., A. milleri sp. n., A. pratchetti sp. n., A. gumperzae sp. n., A. rothi sp. n., A. ricei sp. n., A. adamsi sp. n., A. nicklei sp. n., A. akanthikos sp. n., A. moctezuma sp. n., A. paradoxa sp. n., A. apaeninsula sp. n., A. hebardi sp. n., A. dnopheros sp. n., A. aquila sp. n., A. florilega sp. n., A. galeana sp. n., A. gurneyi sp. n., A. pumila sp. n., A. hypogaios sp. n., A. diaphana sp. n., A. nocturna sp. n., A. alichenas sp. n. All species are described or redescribed, major morphological features are illustrated, distributions are characterized, and the biology of the species is reviewed. A neotype series is designated for A. investigata Friauf & Edney.;The phylogenetic relationships between 24 species of the Corydiid cockroach genus Arenivaga were investigated using morphological and molecular data. The molecular dataset included the following markers: the nuclear gene histone III (H3), the mitochondrial ribosomal RNA gene 12S (12S), and the mitochondrial cytochrome c oxidase I gene (CO1). The phylogenetic relationships of these 24 species were then explored using three optimality criteria: parsimony, maximum likelihood and Bayesian analyses. The putative sister genus Eremoblatta and more distantly related Blatta orientalis were used as outgroups. A partitioned Bremer analysis was performed to provide some insight into which portions of the data provided the most evolutionary insight into this unusual group of insects. All analyses confirm the genus is monophyletic. Several relationships within the genus are recovered with strong support. Both the parsimony and likelihood estimations fail to provide good resolution along the backbone of the generic tree, whereas the Bayesian estimation resolves most nodes. Most of the strongly supported relationships are reinforced by both geographical distribution and genitalicl morphology.;The relative contributions of 23 ecological variables to the niche of the genus Arenivaga were examined. This analysis revealed that more than 95% of their ecological niche could be described by eight variables: soil, isothermality, minimum temperature of the coldest month, mean temperature of the driest quarter, annual precipitaliction, precipitaliction of the driest month, precipitaliction of the wettest quarter and ground cover. These eight variables with respect to their relative contributions to the niche of the genus as a whole as well as the individual niches of 27 species in the genus were then examined. This revealed the similarity of niche composition of most of the species, as well as how varied the niches were of several species. A species dendrogram built from similarity of contribution of the eight variables to niche composition was compared to a phylogeny of the genus, but few similarities in topology were found. This analysis revealed that soil is the most important contributor to these species' niches, followed by precipitaliction of the driest month, and finally, precipitaliction of the wettest quarter. It also confirmed that the majority of Arenivaga species have niches comprised of similar, but not identical, proportions of as few as four, and as many as eight ecological variables. Currently there is no evidence to support niche conservatism between closely related species, indicating that adapting to new and variable niches is one of the drivers of speciation in this genus.