A molecular phylogeny of the gastropod family Haminoeidae sensu lato (Heterobranchia: Cephalaspidea): a generic revision

Abstract

Haminoeidae is the most diverse family of Cephalaspidea with 13 to 17 genera commonly recognised as valid and with 46 genera that historically have been moved back and forth between Haminoeidae and other families. Due to poor definition of most genera the family is plagued by extensive taxonomic confusion and its generic composition and internal relationships remain uncertain. In this work we have integrated the study of type material, original descriptions, shells, morpho-anatomical data, and molecular phylogenetics (Bayesian, maximum likelihood, and maximum parsimony) based on five genetic markers (the mitochondrial genes cytochrome c oxidase subunit I and 16SrRNA and the nuclear genes 18SrRNA, 28SrRNA, and histoneH3) to delimit the valid genera, define synapomorphic traits, and establish synonym lists. Three hundred and ninety novel sequences were generated. In total 14 genera were recognised; one genus (Vellicolla gen. nov.) is here described as new and an additional fifteenth group was identified, but no species could be formally ascribed to it and therefore remains unnamed (here designated informally as mini-haminoeids). The relationships of genera are discussed and seven deep clades have been identified but are not formally named because of lack of recognisable synapomorphies for several of them. A new classification for Haminoeidae is proposed including 14 valid genera and one informal group.

The copulatory apparatus of the marine gastropod Haminella solitaria (Heterobranchia: Cephalaspidea) and its phylogenetic relevance

“…In the latest phylogeny of the family Haminoeidae, the genera Atys Montfort 1810 and Haminella are sister clades. In the genus Atys the prostate is connected to the side of the penial sheath, a shared apomorphy with the hypothesized sister genus Haminella (Oskars et al, ), in which the seminal duct opens laterally on the distal region of the atrium. Conversely, in other species included in the genus Atys ( A. multistriatus , A. pittmani ) the seminal duct is attached to the distal tip of the penial sheath (Too, Carlson, Hoff, & Malaquias, ).…”

“…The hermaphroditic marine snail species Haminella solitaria ( Say 1822) was formerly included in the genus Haminoea Turton & Kingston (in Carrington) 1830, but in a recently published molecular phylogeny of the family Haminoeidae it was assigned to the genus Haminella Thiele 1925 (Oskars et al, ). This small cephalaspidean gastropod is native to the Atlantic coast of North America, occurring in shallow and tidal sandy mud flats from the Gulf of Saint Lawrence to Florida.…”

“…The order Cephalaspidea comprises ~634 known species of marine gastropods living in shallow and deep waters, from tropical to polar seas, distributed into several families (Malaquias, Dodds, Bouchet, & Reid, ; Oskars, Bouchet, & Malaquias, ). The largest is the family Haminoeidae, which, according to the latest review, encompasses 14 genera, totaling ~115 valid species (Oskars et al, ).…”

“…The type species, H. hydatis ( Linnaeus 1758), and the other six native European species of the genus Haminoea (Malaquias & Cervera, ), plus the northeastern Pacific species H. vesicula ( Gould 1855) (see Gibson & Chia, ), H. alfredensis Bartsch 1915 from South Africa, and H. antillarum ( d'Orbigny 1841) from tropical western Atlantic (Thompson, ) have a bilobed prostate and a muscular penis (Figure A). All of these species form a clade in the new phylogenetic tree of the family Haminoeidae, whereas the species with a single‐lobed prostate (Figure B) previously assigned to the genus Haminoea are now placed in the genera Bakawan , Haminella , Haloa , Lamprohaminoea , and Papawera (Oskars & Malaquias, ; Oskars et al, ).…”

“…Therefore, in light of the new phylogenetic framework hypothesized by Oskars et al () for the family Haminoeidae, it becomes extremely important to investigate the internal anatomy, histology, and ultrastructure of the copulatory apparatus in more genera and species of the various clades of the family to evaluate and understand the taxonomic relevance of the morphofunctional features and the evolution of this apparatus. The general morphology of the copulatory apparatus in Haminella solitaria was previously reported by Rudman () and Marcus (), but histological and ultrastructural data were not presented.…”