Taxonomic Identity of Two Amnicolid Gastropods of Conservation Concern in Lakes of the Pacific Northwest of The

Journal of The Malacological Society of London Molluscan Studies Journal of Molluscan Studies (2016) 82: 464–471. doi:10.1093/mollus/eyw009 Advance Access publication date: 13 May 2016 Taxonomic identity of two amnicolid gastropods of conservation concern in lakes of the Pacific Northwest of the USA Hsiu-Ping Liu1, Darcy Marceau1 and Robert Hershler2 1Department of Biology, Metropolitan State University of Denver, Denver, CO 80217, USA; and 2Department of Invertebrate Zoology, Smithsonian Institution, PO Box 37012, Washington, DC 20013-7012, USA Correspondence: R. Hershler; e-mail: [email protected] Downloaded from (Received 14 January 2016; accepted 1 April 2016) ABSTRACT In this paper we attempt to clarify the identity of two purportedly new species of amnicolid snails in Pacific Northwest lakes that were vaguely described in grey literature and recently petitioned for federal http://mollus.oxfordjournals.org/ listing. As currently understood the western American amnicolid fauna consists of the endemic genus Colligyrus (three species) and Amnicola limosa, which is distributed in a single site in western Montana (and also throughout much of eastern North America). The ‘Washington duskysnail’ was proposed for the Montana population of A. limosa and two recently discovered populations in northern Washington. The ‘masked duskysnail’ is a small amnicolid of uncertain generic status from two lakes in northern Washington. Our assessment of these putative species was based on genetic and morphological study of specimens from previously reported sites and recently discovered localities in Montana (both snails) and Washington (the first only). Molecular analyses (based on the mtCOI gene) resolved the western American populations of Amnicola as a weakly supported subunit of a clade that also contained eastern at smithsonia3 on July 17, 2016 A. limosa and A. dalli; the western Amnicola differed from eastern A. limosa and A. dalli by 2.1% mean se- quence divergence. We also found that western Amnicola and eastern A. limosa do not differ in body pigmentation as previously postulated and that these snails are closely similar in all other morphological details. We conclude that the Washington duskysnail is not a distinct species and that all of the western populations of Amnicola are A. limosa. This finding extends the range of A. limosa westward almost to the Pacific margin. Our molecular phylogenetic analyses and study of the female reproductive anatomy of the masked duskysnail congruently indicated that this snail, which was previously compared with other western amnicolids, belongs to the genus Lyogyrus, which is otherwise restricted to eastern North America. We were unable to resolve the taxonomic status of the masked duskysnail further, owing to the paucity of pertinent data for the poorly known eastern Lyogyrus fauna. We recommend that the masked duskysnail be treated as ‘Lyogyrus sp.’ pending further study of this genus. INTRODUCTION identified in grey literature (i.e. unpublished contract reports) The Amnicolidae are a medium-sized (150–200 species; Strong and subsequently become focal points of attention of state and et al., 2008) family of freshwater caenogastropods distributed in federal land management agencies and conservation organiza- temperate Asia, Europe and North America (Wilke et al., 2013). tions. This is the second of two papers in which we evaluate the As currently understood, the western North American amnicolid taxonomic status of these purported new species. Previously we fauna is composed of the three species in the genus Colligyrus, showed that the ‘Columbia duskysnail’, distributed in springs in which live in springs and streams in portions of the northwestern the lower Columbia River basin, is a broadly disjunct subunit of United States (Hershler, 1999; Hershler et al., 2003); and C. greggi (Liu, Hershler & Roessell, 2015). The present study Amnicola limosa (Say, 1817), which is distributed in a single lake focuses on two amnicolids of conservation concern in Pacific in Montana (Taylor & Bright, 1987: 252) and also throughout Northwest lakes. much of eastern North America. A second western population of The vernacular name ‘Washington duskysnail’ was used for A. limosa (in Utah Lake) is apparently extinct (Taylor & Bright, the first reported western population of A. limosa and two 1987; Oliver & Bosworth, 1999). During the past few decades recently discovered populations in northern Washington (Frest & several putatively undescribed western amnicolids have been Johannes, 1995; WDNR, 2007). Frest & Johannes (1995) vaguely Published by Oxford University Press on behalf of The Malacological Society of London 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US. IDENTITY OF AMNICOLIDS IN PACIFIC NORTHWEST LAKES differentiated this supposedly new species from eastern North MATERIAL AND METHODS American A. limosa by several details of body pigmentation. There have been no subsequent studies of the Washington duskys- For the molecular component of the project we sequenced speci- nail, which was recently petitioned for addition to the Federal mens of Amnicola limosa from the previously reported site in List of Endangered and Threatened Wildlife (USFWS, 2009). Montana (McWennegar Slough) and seven recently discovered The ‘masked duskysnail’ is a small amnicolid from two sites in localities (lakes) in western Montana and northern Washington northern Washington that is currently protected under the Survey (herein we refer to these populations collectively as ‘western and Manage Program of the Northwest Forest Plan (USDA & Amnicola’). Specimens of the masked duskysnail were sequenced USDI, 2007) and was recently petitioned for federal listing from the two previously reported sites in northern Washington (USFWS, 2012). Clarke (1976: 5) reported the discovery of this “ap- and two recently discovered localities (lakes) in western parently new species of Lyogyrus”inFishLake(ChelanCounty) Montana. The locations of these sites are shown in Figure 1. The without additional comment. Lyogyrus, as currently constituted, is sequenced specimens were either recently (2014) collected by us restricted to eastern North America (Thompson, 1968; Thompson (and preserved in 90% ethanol in the field) or obtained from & Hershler, 1991). Frest & Johannes (1995: 185) stated that the samples in the Smithsonian Institution’s National Museum of masked duskysnail is a new species of Lyogyrus whose “shell shape Natural History (USNM) collection. In order to facilitate com- and pigment pattern are distinctive as compared to previously parisons we also sequenced specimens of the type species of described forms,” but did not elaborate further. In a subsequent Lyogyrus (there are no previously published sequences for this field guide aiming to ‘survey and manage’ freshwater molluscs, Frest genus in GenBank) and three A. limosa populations from eastern & Johannes (1999) figured the headfoot and several shells of the masked duskysnail and differentiated this supposedly new species from other western amnicolids (in a key) by its elongate shell and Downloaded from ‘mask’ of pigment around the eyes. The masked duskysnail was recently assigned to Colligyrus, without explanation, in an unpublished report (Johannes, 2011); this classification was subsequently followed by the USFWS (2012). At present there is no well corroborated evidence supporting recognition of either the Washington duskysnail or the masked http://mollus.oxfordjournals.org/ duskysnail as new species. The USFWS (2012: 57925) cited the absence of this information in ruling that the masked duskysnail does not constitute a listable entity under the Endangered Species Act. Indeed, the scant morphological description of the masked duskysnail is not sufficient to determine whether it belongs to Colligyrus or Lyogyrus, closely similar genera that are differentiated by details of female reproductive anatomy (Hershler, 1999). Here we attempt to clarify the identity of these two purportedly new species based on morphological study and analysis of mt COI Figure 1. Map of the northwestern United States showing the collecting sequences. We also briefly discuss our findings as they relate to the localities for western Amnicola and Masked duskysnail samples used in at smithsonia3 on July 17, 2016 systematics of North American Amnicolidae. the molecular analysis. Specimen codes are from Table 1. Table 1. Samples that were newly sequenced (for COI) for this study, with codes (used in Figs 1 and 2), locality and voucher details, and GenBank accession numbers. Taxon Code Locality (voucher material) GenBank accession number Western Amnicola AM5, AM11 Pattison Lake, east side at Washington Department of Fish and Wildlife boat ramp, KU991117, KU991123 Thurston Co., WA (USNM 1163822, USNM 1258916) AM6 Bonaparte Lake, south end at campground, Okanogan Co., WA (USNM 1256490) KU991118, KU991119 AM7 Curlew Lake at state park west of Hwy 21, Ferry Co., WA (USNM 1256491) KU991120 AM8 Spectacle Lake, south side, near resort, Okanogan Co., WA (USNM 1258913) KU991121 AM9 Leader Lake, north side near dam, Okanogan Co., WA (USNM 1258914) KU991122 AM12 McWennegar Slough, south side near Hwy 35, Flathead Co., MT (USNM 1263000) KU991124, KU991125 AM15 Brown’s Lake, cutoff pond along northeast side, Powell Co., MT (USNM 1263003) KU991126, KU991127 AM16 Georgetown Lake, east side north of Stuart Campground, Granite Co., MT (USNM 1253360) KU991128, KU991129 Amnicola limosa AM2 Clinton River

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