Species boundaries of Gulf of Mexico vestimentiferans (Polychaeta, Siboglinidae) inferred from mitochondrial genes

Maria Pia Miglietta,Stephane Hourdez,Dominique A Cowart,Stephen W Schaeffer,Charles Fisher

doi:10.1016/j.dsr2.2010.05.007

Maria Pia Miglietta, Stephane Hourdez + Show 3 more

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https://doi.org/10.1016/j.dsr2.2010.05.007

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Journal: Deep-Sea Research Part II	Publication Date: May 24, 2010
Citations: 35	License type: cc-by

Affiliation: Pennsylvania State University

Abstract

At least six morphospecies of vestimentiferan tubeworms are associated with cold seeps in the Gulf of Mexico (GOM). The physiology and ecology of the two best-studied species from depths above 1000m in the upper Louisiana slope (Lamellibrachia luymesi and Seepiophila jonesi) are relatively well understood. The biology of one rare species from the upper slope (escarpiid sp. nov.) and three morphospecies found at greater depths in the GOM (Lamellibrachia sp. 1, L. sp. 2, and Escarpia laminata) are not as well understood. Here we address species distributions and boundaries of cold-seep tubeworms using phylogenetic hypotheses based on two mitochondrial genes. Fragments of the mitochondrial large ribosomal subunit rDNA (16S) and cytochrome oxidase subunit I (COI) genes were sequenced for 167 vestimentiferans collected from the GOM and analyzed in the context of other seep vestimentiferans for which sequence data were available. The analysis supported five monophyletic clades of vestimentiferans in the GOM. Intra-clade variation in both genes was very low, and there was no apparent correlation between the within-clade diversity and collection depth or location. Two of the morphospecies of Lamellibrachia from different depths in the GOM could not be distinguished by either mitochondrial gene. Similarly, E. laminata could not be distinguished from other described species of Escarpia from either the west coast of Africa or the eastern Pacific using COI. We suggest that the mitochondrial COI and 16S genes have little utility as barcoding markers for seep vestimentiferan tubeworms.

Highlights

At least six morphospecies of vestimentiferan tubeworms are associated with cold seeps in the Gulf of Mexico (GOM)
We present phylogenetic hypotheses based on the mitochondrial large ribosomal subunit rDNA gene (16S) and mitochondrial cytochrome oxidase 1 gene (COI) of over 200 vestimentiferans including 180 individuals from the six morphospecies that occur in the Gulf of Mexico
The genetic analyses confirmed identification of most of the morphological species during collections, we identified an unexpected discrepancy between the morphospecies identified during the collections and genealogical species identified using the mitochondrial genes cytochrome oxidase subunit I (COI) and 16S

Summary

Introduction

At least six morphospecies of vestimentiferan tubeworms are associated with cold seeps in the Gulf of Mexico (GOM). Lamellibrachia luymesi (van der Land and Narrevang, 1975) and Seepiophila jonesi (Gardiner et al, 2001), are relatively well studied, and their ecology and physiology are well understood (Bergquist et al, 2002; Cordes et al, 2007a, b). They occur on the upper Louisiana slope at between 500 and 950 m depth and occasionally co-occur with a rare undescribed species, escarpiid sp. We compared between- and within-species 16S and COI genetic distances and show that these two mitochondrial genes have little utility as ‘‘barcoding molecules’’ for vestimentiferans

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