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

Abstract

Yumtaax Boucher (Coleoptera: Passalidae) is an endemic genus from the temperate sierras of Mexico and includes six narrowly distributed species. Yumtaax species have been assigned to several genera of Passalidae throughout history, and a phylogenetic approach is necessary to understand species delimitation and interspecific relationships. This study reconstructed the molecular phylogeny of six Yumtaax morphotypes using parsimony and Bayesian analysis of DNA sequence data from the ribosomal nuclear gene region 28S and the mitochondrial gene regions 12S and cytochrome oxidase I (COI) in addition to morphological characters. Analyses recovered two well-supported Yumtaax clades (the Yumtaax laticornis and Yumtaax imbellis clades) that are possible sister lineages. One synapomorphic morphological character state and the geographic isolation of the group provide corroborative evidence for monophyly. Molecular phylogenetic analyses and traditional morphological examinations also resulted in the discovery of two undescribed Yumtaax species and the discovery of two separate evolutionary lineages (cryptic species) within Yumtaax recticornis. As a result we describe three new species (Yumtaax veracrucensis Beza-Beza, Reyes-Castillo & Jameson, sp. n., Yumtaax cameliae Beza-Beza, Reyes-Castillo & Jameson, sp. n., and Yumtaax jimenezi Beza-Beza, Reyes-Castillo & Jameson, sp. n.), redescribe two species (Yumtaax recticornis [Burmeister 1847] and Yumtaax laticornis [Truqui 1857]), and provide a key to all nine Yumtaax species. This study is one of two studies to use molecular data to evaluate the evolutionary relationships of a genus of Bess Beetles (Passalidae), an ecologically important insect group exhibiting low morphological variability and heretofore lacking molecular phylogenetic study.

Tonantzin, a New Genus of Bess Beetle (Coleoptera, Passalidae) from a Montane Subtropical Forest in Central Mexico, with a Review of the Taxonomic Significance of the Mesofrontal Structure in Proculini

“…But besides these characters, Tonantzin tepetl is clearly morphologically distinct from P. jalapensis . For instance, Tonantzin does not agree with the current concept of Petrejoides , a genus with unclear circumscription [1], and one that has also been recovered as polyphyletic [9]. Petrejoides sensu Boucher [1] is circumscribed based on a single autapomorphy––the convex, curved and narrow anterior border of the clypeofrons.…”

“…The mesofrontal structure [5]; (“mediofrontal structure”/”medio-post-frontal structure” of some recent workers) has long been important in the classification of Proculini and Passalidae in general, e.g., [8,12,28]. As demonstrated by recent taxonomic and phylogenetic studies, e.g., [9,29,30,31], it is clear that characters of the mesofrontal structure (MFS) and their states continue to form important components of the generic- and species-level classification of Proculini. However, we highlight a distinct shift in the application of the MFS to Proculini taxonomy, recognition of which prompted us to explore the morphology of the MFS in light of the discovery of Tonantzin .…”

“…Some montane species in Mexico also show an extreme degree of local endemism. For instance, Y. laticornis is only known from Pico de Orizaba, Veracruz, and Y. cameliae is known only from a small patch of oak forest in Puerto del Aire, Acutzingo, Veracruz [9]. Both of these species are known from altitudes above 2000 masl.…”

“…The PCR reactions for 28s had a final volume of 21 μl each including 1.20× CoralLoad PCR buffer, 1.20× Q solution, 0.11 μM dNTP mix, 1.79 μM MgCl2, 0.71 μM of each primer, and 1.0 μL of DNA (concentration was variable for each sample). Both fragments were amplified following a modified cycling pattern from Beza-Beza et al [9]: (1) 94 °C for 2 min, (2) 94 °C for 40 s, (3) 52 °C for 40 s, (4) 68 °C for 2.5 min, steps 2 to 4 were repeated for 30 cycles, followed by (5) 68 °C for 5 min. Primer sequences are described in Table S1.…”

“…Although changes to some generic concepts were proposed by Boucher [1], not all of those changes have been followed by other passalid workers [6,7]. Taxonomic work on Proculini in Mexico has mainly focused on the description of new taxa, either in isolation, e.g., [6,7], or in the context of larger group revisions, e.g., [8,9]. The last genus to be described for Mexico was Yumtaax , species of which represented a new circumscription of the Petrejoides “ recticornis ” species group sensu Castillo & Reyes-Castillo [8], as well as the recognition of a new rank.…”