Jerry D. Kudenov

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.

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.

Regeneration of posterior segments and terminal structures in the bearded fireworm, Hermodice carunculata (Annelida: Amphinomidae)

Like many other annelids, bearded fireworms, Hermodice carunculata, are capable of regenerating posterior body segments and terminal structures lost to amputation. Although previous research has examined anterior regeneration in other fireworm species, posterior regenerative ability in fireworms remains poorly studied. As the morphology of the anal lobe (a small, fleshy terminal structure of unknown function) has been used to distinguish East and West Atlantic H. carunculata populations, there is a more imminent need to understand the morphology and organization of tissues in specimens undergoing posterior regeneration, and the timeframe in which significant developmental changes occur. To further investigate this phenomenon, we amputated the posterior segments of living H. carunculata specimens collected from the Gulf of Mexico and monitored posterior regeneration over a 6‐month study period. Although many aspects of posterior regeneration in H. carunculata are consistent with the findings of other annelid regeneration studies, histological analysis revealed that once formed, anal lobe morphology remains relatively unchanged at all stages of posterior regeneration; East Atlantic morphotypes were not observed in the West Atlantic specimens studied here. Additionally, we found that the ventral nerve chord, which is partially responsible for the regeneration of lost body parts in polychaete annelids, terminates within the anal lobe, suggesting that this structure may play a role in the formation of new segments. J. Morphol. 275:1103–1112, 2014.

Complex morphology in a simple chemical system

Chemical systems, far from thermodynamic equilibrium, may spontaneously self-construct complex structures mimicking biological structures.