Cryptic diversity in Andrognathus corticarius Cope, 1869 and description of a new Andrognathus species from New Mexico (Diplopoda, Platydesmida, Andrognathidae)

Abstract

Andrognathus is a genus of small, thin-bodied millipedes found in deciduous forests of North America. Poorly understood, these organisms inhabit decaying wood and have morphologically conserved and difficult-to-identify sexual characters that have limited study historically. Recent use of scanning electron microscopy has uncovered variation in male genitalia that was previously unknown in the genus. The distribution of Andrognathus and the extent of this variability across the continent, however, were undocumented, and a wealth of natural history collections remained uncatalogued. Here a new species of Andrognathus is described from New Mexico, Andrognathusgrubbsisp. n., natural history collections are utilized to create a comprehensive map of the genus, and a neotype established for the type species, Andrognathuscorticarius Cope, 1869. Analysis of the cytochrome oxidase I gene (COI) for A.corticarius was completed for the type series and individuals across the species distribution, but little variation was found. Andrognathusgrubbsisp. n. joins A.corticarius and A.hoffmani Shear & Marek, 2009 as the only members of the genus.

First steps toward suctorial feeding in millipedes: Comparative morphology of the head of the Platydesmida (Diplopoda: Colobognatha)

“…There is variation within the Platydesmida regarding the presence of an entire or composite mentum (promentum + eumentum). An entire mentum is, for example, present in Brachycybe (this study), Platydesmus (Attems, 1951; therein as nomen nudum Raphonotum ), Andrognathus (Shorter et al, 2018), Gosodesmus (this study), and Pseudodesmus (this study). A divided mentum is present in Dolistenus (Attems, 1951; Mauriès, 2015; this study) and Ebenostenus (Mauriès, 2015).…”

“…99 mya (Moritz & Wesener, 2019; Wesener & Moritz, 2018). The Platydesmida often occur in large aggregations (Lewis, 1984; Shorter et al, 2018; Wong et al, 2020). They are fungivorous (Gardner, 1975; Lewis, 1984; Macias et al, 2019) and assumed to show a suctorial liquid‐feeding mode (Lewis, 1984; Macias et al, 2019; Wong et al, 2020).…”

“…The external morphology of the Platydesmida has been described for various taxa (Attems, 1951; Gardner, 1975; Mauriès, 2015; Recuero & Rodríguez‐Flores, 2020; Shorter et al, 2018; Wong et al, 2020). The internal morphology and the muscular system have so far been described for the body rings and legs of Dolistenus savii Fanzago 1876 by Manton (1961, 1977), who also illustrated some muscles of the head.…”

The first true millipede—1306 legs long

“…Tissues were dissected from ethanol preserved specimens and DNA extracted from them according to ref. 39 . 6–10 rings were removed and pulverized with a micro-pestle in 200 uL lysis buffer containing proteinase K using a Qiagen DNeasy kit.…”

“…Standard DNA cytochrome oxidase I gene (COI) barcodes for the holotype specimen, and two juveniles were sequenced with the primer pair LCO1490 and HCO2198 according to methods in ref. 39 (NCBI accession #: OK602741).…”