Description of a new species of cryptic snubnose darter (Percidae: Etheostomatinae) endemic to north-central Mississippi

Abstract

Many subclades within the large North American freshwater fish genus Etheostoma (Percidae) show brilliant male nuptial coloration during the spring spawning season. Traditionally, perceived differences in color were often used to diagnose closely related species. More recently, perceived differences in male nuptial color have prompted further investigation of potential biodiversity using genetic tools. However, cryptic diversity among Etheostoma darters renders male nuptial color as unreliable for detecting and describing diversity, which is foundational for research and conservation efforts of this group of stream fishes. Etheostoma raneyi (Yazoo Darter) is an imperiled, range-limited fish endemic to north-central Mississippi. Existing genetic evidence indicates cryptic diversity between disjunctly distributed E. raneyi from the Little Tallahatchie and Yocona river watersheds despite no obvious differences in male color between the two drainages. Analysis of morphological truss and geometric measurements and meristic and male color characters yielded quantitative differences in E. raneyi from the two drainages consistent with genetic evidence. Morphological divergence is best explained by differences in stream gradients between the two drainages. Etheostoma faulkneri, the Yoknapatawpha Darter, is described as a species under the unified species concept. The discovery of cryptic diversity within E. raneyi would likely not have occurred without genetic tools. Cryptic diversity among Etheostoma darters and other stream fishes is common, but an overreliance on traditional methods of species delimitation (e.g., identification of a readily observable physical character to diagnose a species) impedes a full accounting of the diversity in freshwater fishes in the southeastern United States.

Systematics of the Stripetail Darter, Etheostoma kennicotti (Putnam), and the Distinctiveness of the Upper Cumberland Endemic Etheostoma cumberlandicum Jordan and Swain

“…Ichthyologists studying the North American freshwater fish fauna are entering the last stages of describing all species of darters. As reflected by research of the past decade, this last phase of biodiversity discovery in darters will likely combine traditional morphological data with genetic and genomic analyses as has been deployed over the past decade (Keck and Near, 2013; Robison et al, 2014; Near and Thomas, 2015; Powers et al, 2015; Kozal et al, 2017; Near et al, 2017, 2021; Sterling and Warren, 2020).…”

Integrating fish swimming abilities into rapid road crossing barrier assessment: Case studies in the southeastern United States

“…Yoknapatawpha Darter, recently split from the Yazoo Darter ( E . raneyi ), has a limited distribution in the Yocona River watershed of north-central Mississippi [ 28 ]. Having been largely channelized and incised, streams in this watershed are characterized by shallow, sandy, homogenous, unstable habitat, and are subject to flashy hydrology [ 29 , 30 ].…”

“…Having been largely channelized and incised, streams in this watershed are characterized by shallow, sandy, homogenous, unstable habitat, and are subject to flashy hydrology [ 29 , 30 ]. Yazoo Darters in the Yocona River watershed had been considered in critical need of conservation [ 30 , 31 ] before the Yoknapatawpha Darter was formally described [ 28 ]. The earliest account of Yoknapatawpha Darter habitat use indicates association with hard clay riffles in forested streams [ 32 ].…”

“…The earliest account of Yoknapatawpha Darter habitat use indicates association with hard clay riffles in forested streams [32]. They are associated with instream cover in less-disturbed streams and anthropogenic structures in more disturbed streams [28]. Habitat degradation and fragmentation have reduced gene flow and population sizes [28,[33][34][35][36].…”

The influence of habitat characteristics on the occupancy and dispersal of two headwater fishes in a dendritic network

“…The goldstripe darter (Bart & Taylor, 1999) is broadly distributed across the southeastern United States, and the Yazoo darter is endemic to the Upper Yazoo River basin (Suttkus et al, 1994; Thompson & Muncy, 1986) and listed as vulnerable by the Southeastern Fishes Council (Warren et al, 2000) and the American Fisheries Society (Jelks et al, 2008). Recently, the Yazoo darter was formally split into two species (Powers & Warren, 2009; Sterling et al, 2012; Sterling & Warren, 2020) in accordance with the stated criteria of the unified species concept (De Queiroz, 2007). The newly described species, the Yoknapatawpha darter ( Etheostoma faulkneri ), is endemic to the YRSB.…”