Taxonomic status of the Columbia duskysnail (Truncatelloidea, Amnicolidae, Colligyrus)

By

Liu, Hsiu-Ping
Hershler, Robert
Rossel, Chris

Type

Article

Date of Publication

2015

Original Publication

ZooKeys

Volume

514

Pages

1-13

Subjects

aquatic , Conservation , Gastropoda , Phylogeny , systematics , Western United States

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/zookeys.514.9919

 

Abstract

Undescribed freshwater snails (Amnicolidae: Colligyrus) from the Mount Hood region (northwestern United States) identified as a new species (commonly known as the Columbia duskysnail) in grey literature have been provided federal protection under the “survey and manage” provisions of the Northwest Forest Plan and have been placed on conservation watch lists. However, there are no published studies of the identity of these snails aside from a molecular phylogenetic analysis which delineated a close relationship between the single sampled population and C. greggi, which is distributed more than 750 km to the east of the Mount Hood area. Here we examine the taxonomic status of the Columbia duskysnail based on additional molecular sampling of mitochondrial DNA sequences (COI) and morphological evidence. We found that the Columbia duskysnail is not a monophyletic group and forms a strongly supported clade with C. greggi. The COI divergence between these broadly disjunct groups (2.1%) was somewhat larger than that within C. greggi (1.0%) but considerably less than that among the three currently recognized species of Colligyrus (8.7–12.1%). Additionally we found that the Columbia duskysnail and C. greggi cannot be consistently differentiated by previously reported diagnostic characters (size and shape of shell spire, pigmentation of body and penis) and are closely similar in other aspects of morphology. Based on these results we conclude that the Columbia duskysnail is conspecific with C. greggi.