Elizabeth Borda

The curious case of Hermodice carunculata (Annelida: Amphinomidae): evidence for genetic homogeneity throughout the Atlantic Ocean and adjacent basins

Over the last few decades, advances in molecular techniques have led to the detection of strong geographic population structure and cryptic speciation in many benthic marine taxa, even those with long‐lived pelagic larval stages. Polychaete annelids, in particular, generally show a high degree of population divergence, especially in mitochondrial genes. Rarely have molecular studies confirmed the presence of ‘cosmopolitan’ species. The amphinomid polychaete Hermodice carunculata was long considered the sole species within its genus, with a reported distribution throughout the Atlantic and adjacent basins. However, recent studies have indicated morphological differences, primarily in the number of branchial filaments, between the East and West Atlantic populations; these differences were invoked to re‐instate Hermodice nigrolineata, formerly considered a junior synonym of H. carunculata. We utilized sequence data from two mitochondrial (cytochrome c oxidase subunit I, 16S rDNA) markers and one nuclear (internal transcribed spacer) marker to examine the genetic diversity of Hermodice throughout its distribution range in the Atlantic Ocean, including the Mediterranean Sea, the Caribbean Sea, the Gulf of Mexico and the Gulf of Guinea. Our analyses revealed generally low genetic divergences among collecting localities and between the East and West Atlantic, although phylogenetic trees based on mitochondrial data indicate the presence of a private lineage in the Mediterranean Sea. A re‐evaluation of the number of branchial filaments confirmed differences between East and West Atlantic populations; however, the differences were not diagnostic and did not reflect the observed genetic population structure. Rather, we suspect that the number of branchial filaments is a function of oxygen saturation in the environment. Our results do not support the distinction between H. carunculata in the West Atlantic and H. nigrolineata in the East Atlantic. Instead, they re‐affirm the older notion that H. carunculata is a cohesive species with a broad distribution across the Atlantic Ocean.

Towards a revised Amphinomidae (Annelida, Amphinomida): description and affinities of a new genus and species from the Nile Deep-sea Fan, Mediterranean Sea

Borda, E., Kudenov, J.D., Bienhold, C. & Rouse, G.W. (2012). Towards a revised Amphinomidae (Annelida, Amphinomida): description and affinities of a new genus and species from the Nile Deep‐sea Fan, Mediterranean Sea. —Zoologica Scripta, 41, 307–325.

Cryptic species of Archinome (Annelida: Amphinomida) from vents and seeps

Since its description from the Galapagos Rift in the mid-1980s, Archinome rosacea has been recorded at hydrothermal vents in the Pacific, Atlantic and Indian Oceans. Only recently was a second species described from the Pacific Antarctic Ridge. We inferred the identities and evolutionary relationships of Archinome representatives sampled from across the hydrothermal vent range of the genus, which is now extended to cold methane seeps. Species delimitation using mitochondrial cytochrome c oxidase subunit I (COI) recovered up to six lineages, whereas concatenated datasets (COI, 16S, 28S and ITS1) supported only four or five of these as clades. Morphological approaches alone were inconclusive to verify the identities of species owing to the lack of discrete diagnostic characters. We recognize five Archinome species, with three that are new to science. The new species, designated based on molecular evidence alone, include: Archinome levinae n. sp., which occurs at both vents and seeps in the east Pacific, Archinome tethyana n. sp., which inhabits Atlantic vents and Archinome jasoni n. sp., also present in the Atlantic, and whose distribution extends to the Indian and southwest Pacific Oceans. Biogeographic connections between vents and seeps are highlighted, as are potential evolutionary links among populations from vent fields located in the east Pacific and Atlantic Oceans, and Atlantic and Indian Oceans; the latter presented for the first time.

Description of a soft-bodied invertebrate with microcomputed tomography and revision of the genus Chtonobdella (Hirudinea: Haemadipsidae)

Two‐jawed (duognathous) terrestrial leeches in the Haemadipsidae are major pests across their wide geographic range, represented by numerous endemic species in Australia and across many islands in the Indian and Pacific Oceans. However, haemadipsid taxonomy, based largely on externally visible characters, remains in conflict with phylogenetic relationships. We capitalize on the power of microcomputed tomography (μCT), allowing for the first description of an extant soft‐bodied species – Chtonobdella tanae sp. n. – using this technology. Several fixation strategies for soft‐bodied invertebrates in μCT scanning applications are also evaluated. Expanding on prior work, higher taxonomy of duognathous haemadipsids also was evaluated with phylogenetic analyses of DNA sequence data. Whereas monophyly of duognathous leeches was supported, substantial conflict remained with respect to named genera. Consequently, the genus Chtonobdella was revised to include all duognathous leech species previously distributed in 31, mostly monotypic genera.

Revamping Amphinomidae (Annelida: Amphinomida), with the inclusion of Notopygos

This study revises the taxonomic status of the formerly monotypic Archinomidae, which is nested within paraphyletic Amphinomidae according to recent phylogenetic work. We focused our taxonomic sampling to evaluate the affinities of Notopygos and genera classified as ‘fusiform’ in body shape, including Archinome and Chloeia. Prior to this study, the phylogenetic placement of Notopygos had not been evaluated. We inferred the phylogenetic relationships of Notopygos within Amphinomidae based on nuclear and mitochondrial markers, and cytochrome c oxidase subunit I genetic divergences of five Notopygos species, including the newly described Notopygos kekooa sp. n. from the Gulf of California. The phylogenetic and morphological evidence, now including Notopygos species, justified the establishment of two subfamilies within Amphinomidae. In accordance with ICZN Article 36 (Principle of Coordination), both subfamilies are presented as status novus in the nomenclature ranks.

Phylogeny and systematics of Aphroditiformia

Aphroditiformia represents one of the most successful radiations of annelids, and is therefore an interesting model to understand morphological and functional evolution. Previous phylogenetic analyses yielded most families as monophyletic but excluded anchialine and interstitial species while failing to recover relationships within Sigalionidae. Here we address these shortcomings through the analysis of four molecular markers and 87 morphological characters sampled across 127 species under the assumptions of parsimony and model‐based methods. Of the 34 newly sequenced taxa, five anchialine and 24 interstitial species were included, with increased representation of Sigalionidae. An additional 28 elusive Sigalionidae taxa were included, represented only by morphological partitions. Molecular and morphological partitions were evaluated under exhaustive sensitivity analyses, testing the effects of alignment algorithms and optimization criteria on tree topologies. Our trees congruently recovered six clades corresponding to the families within Aphroditiformia: Acoetidae, Aphroditidae, Eulepethidae, Iphionidae, Polynoidae and Sigalionidae, respectively. An anchialine polynoid lineage was nested among strictly deep sea species, and interstitial pisionids and pholoids formed two independent clades nested within Sigalionidae. Additionally, Sigalionidae resulted in four clades, defined by combinations of apomorphies, and hereby we propose the subfamilies Pelogeniinae, Pholoinae, Pisioninae, Sthenelanellinae, as well as the provisionally included polyphyletic Sigalioninae.

Euphrosinidae (Annelida: Amphinomida) collected from Antarctica (R/V Polarstern, 1984, 1986) with comments on the generic placement of Euphrosine magellanica Ehlers, 1900

Abstract The Euphrosinidae (Polychaeta: Amphinomida) collected during cruises of the R/V Polarstern, and described by Hartmann-Schröder & Rosenfeldt (1988, 1992) are re-examined. In all, four of five species are here assigned to two previously described taxa: Euphrosine monroi, and Euphrosinella cirratoformis and a fifth species, Euphrosine antarctica, is newly referred to the genus Euphrosinopsis, as a new combination. Euphrosinopsis antarctica n. comb., has priority as type species of the genus, rendering Euphrosinopsis antipoda as the junior synonym. We suggest that Euphrosine magellanica is a misidentified Euphrosinella cirratoformis. Previous Antarctic records of Euphrosine cirrata are also referred to the genus Euphrosinella Detinova, 1985, and are likely E. cirratoformis. Diagnoses or additional descriptive information and appropriate illustrations are provided for all taxa.