A hypothetical evolutionary history of passalid beetles narrated by the comparative anatomy of the hindgut (Coleoptera: Passalidae)

Abstract

When seen as a whole, the hindgut, more than any other section of the digestive tube, provides insights for the taxonomy of higher-level taxa of Passalidae. This comparative cladistics study utilized parsimony analyses, with 57 terminal taxa (including five outgroups) and 18 characters from the ileum of most genera of passalid beetles (Coleoptera: Passalidae), which resulted in a single tree. Based on the results and the topology of the cladogram, the following classification was adopted: (Aulacocyclinae (Solenocyclinae (Proculinae (Passalinae, Macrolininae)))). Three subfamilies (Solenocyclinae, Proculinae, and Macrolininae) are here elevated from the tribal level to the subfamily level. The subfamily Passalinae is redefined and no longer contains any tribes. The family-group name Leptaulacinae is placed in synonym with Solenocyclinae and the family-group name Ceracupedini is placed in synonymy with Aulacocyclinae.

Elongated hindguts in desert‐living dung beetles (Scarabaeidae: Scarabaeinae) feeding on dry dung pellets or plant litter

“…1) is a simple tube of approximately the same width as the midgut in dung and pellet feeders, and a little wider in litter feeders. This morphology is characteristic of adult fresh‐dung feeders within the Scarabaeinae (Umeya,1960; Miller,1961; Edmonds,1974; Lopez‐Guerrero,2002), whereas many other larval or adult Scarabaeoidea (e.g., Wiedemann,1930; Umeya,1960,1974; Lopez‐Guerrero,2002; Egert et al,2005, Fonseca et al,2011) have a differentiated hindgut with at least one expansion behind the pylorus. H/B values are 0.7–0.8, 1.0–1.4, and 2.0–2.5 in dung, pellet, and litter feeders, respectively (Table 1), and thus increase with the content of coarse plant fragments in the ingested food.…”

Two new species of Passalus Fabricius (Coleoptera: Passalidae) from the western Brazilian Amazon with comments on the taxonomic limits of the subgenera

“…The terminology for the cephalic capsule and mandibles follows Boucher (2006) with the addition of the structure "cephalic nodule" = "mamelão" sensu Luederwaldt (1931); other parts of the body follow Reyes-Castillo (1970). The classification of the family follows Fonseca et al (2011), while the classification of Passalus follows Luederwaldt (1931), Hincks & Dibb (1935, 1958 and Reyes-Castillo (1970). Diagnosis: medium sized specimens (22-25 mm total length); body convex; anterior frontal edge straight or slightly convex coarsely punctated; posterior mediofrontal area with large and rounded cephalic nodule; latero + mediofrontal tubercles large and conspicuous, with acute apices attached to inner tubercles (which are larger and with rounded apices) by weak anterofrontal ridges; small secondary mediofrontal tubercles, smaller than the latero + mediofrontal tubercles, with acute apices, near to each other; secondary laterofrontal tubercles nearly inconspicuous with slightly obtuse apices; posterofrontal ridges strong, elevated and straight, attached to the central tubercle, which is small, flat, with only apex pronounced; lateroposterior tubercles conspicuous and transverse; mentum with a dilated mediobasal area and large, deep lateral scars; anterior angles of pronotum acute and protruded; mesosternal scars shallow, triangular-shaped, with opaque surface and presence of micro bristles; metasternal disc barely delimited, with group of punctures in posterior region; metasternal lateral grooves narrow and glabrous; aedeagus elongated and narrow, median lobe elongated, larger than basal piece and parameres together, containing two sclerotized plates (ventral view); parameres separated from basal piece by conspicuous suture (ventral view).…”

Phylogeny of the genus Yumtaax Boucher (Coleoptera, Passalidae, Proculini): Taxonomic and evolutionary implications with descriptions of three new species

“…The tumultuous nomenclatural history of Yumtaax species is due in part to the lack of molecular phylogenetic study of generic relationships in Passalidae . Most phylogenetic studies in the family have concentrated on the resolution of deeper relationships (subfamily and tribal level) (e.g., Fonseca 1987 , Gillogly 2005 , Boucher 2006 , Fonseca et al 2011 ) or have addressed the phylogeny of genera using morphology alone (e.g., Marshall 2000 , Schuster et al 2003 , Boucher 2015 , Jiménez-Ferbans and Reyes-Castillo 2015 ). The most complete generic-level phylogenetic analysis of Passalidae is that of Boucher (2006) , who conducted a phylogenetic analysis of the tribe Proculini based on 51 morphological characters.…”