Phylogenetic systematics of the enigmatic genus Horologion Valentine, with description of a new species from Bath County, Virginia (Coleoptera, Carabidae, Trechinae, Horologionini)
Data files
Jan 12, 2024 version files 37.92 MB
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Horologion.MatricesAndAnalyses.nex
37.92 MB
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README.md
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Abstract
Horologion Valentine, one of the rarest and most enigmatic carabid beetle genera in the world, was until now known only from the holotype of Horologion speokoites Valentine, discovered in 1931 in a small cave in West Virginia. A single specimen of a new species from Virginia was collected in 1991, but overlooked until 2018. DNA sequence data from specimens of this new species, Horologion hubbardi sp. nov., collected in 2022 and 2023, as well as a critical examination of the external morphology of both species, allow us to confidently place Horologion in the supertribe Trechitae, within a clade containing Bembidarenini and Trechini. A more specific placement as sister to the Gondwanan Bembidarenini is supported by DNA sequence data. Previous hypotheses placing Horologion in or near the tribes Anillini, Tachyini, Trechini, Patrobini, and Psydrini are rejected. The existence of two species of Horologion on opposite sides of the high mountains of the middle Appalachians suggests that these mountains are where the ancestral Horologionpopulations dispersed from, and predicts the discovery of additional populations and species. All specimens of H. hubbardi were collected in or near drip pools, and most were found dead, suggesting that the terrestrial epikarst, rather than caves, is the true habitat of Horologion, which explains their extreme rarity since epikarst has not been directly sampled. We recognize the tribe Horologionini, a relict lineage without any close relatives known in the Northern Hemisphere, and an important part of Appalachian biodiversity.
https://doi.org/10.5061/dryad.73n5tb33p
This file is intended to be opened in Mesquite (http://mesquiteproject.org). Contains DNA sequence data from eight genes, sampled from 259 carabid beetles. Matrices of individual genes and a concatenated matrix, as well as all trees resulting from analyses of this data, are included.
When opened in Mesquite, it displays six tabs. The “Taxa” tab includes a list of the 259 beetles and their associated voucher codes, as well as GenBank accession numbers for each of the sequences obtained. The “Character matrices” tab is a list of the matrices of DNA sequence data in the file. The user may view each of these by right clicking and selecting “Show”. The “Tree blocks” tab includes a list of trees obtained from maximum likelihood analysis of the DNA sequence data in the file. The last on the list is a block of hypothetical tree topologies used to test support of various clades.
The last three tabs are tree windows. The one titled “IQ-TREE ML Trees” is a set of all of the Maximum Likelihood trees obtained from each matrix in the dataset, with one tree visible at a time. The user may scroll between these using the arrows in the upper left. The name of the tree, including the abbreviation of the gene, is visible at the bottom of the screen while viewing it. The other two tree windows, titled “Consensus of *IQ-TREE Bootstrap Trees (Matrix: 8gene” and “IQ-TREE UF Bootstrap Trees (Matrix: 8gene.concatenated)” are showing a maximum likelihood consensus tree and Ultrafast Bootstrapping tree, respectively. By default, both are showing these tress from the concatenated 8-gene matrix. The user may view bootstrap trees from other genes by using the Tree menu; for the standard bootstrap consensus window, select “Tree> Tree Block (for Consensus Tree)>” and then select the block of Bootstrap Trees from the gene of interest; for ultrafast bootstrap trees, select “Tree> Tree Block (for Tree Window)” and select the IQ-TREE UF Bootstrap tree from the gene of interest.
The DNA sequence data in this file can be exported in a variety of formats and used in virtually any phylogenetic analysis program.