Speciation in the dark: diversification and biogeography of the deep-sea gastropod genus Scaphander in the Atlantic Ocean.
J Biogeogr. 2015 May; 42(5):843-855.JB

Abstract

AIM

The aim of this work was to improve understanding about the mode, geography and tempo of diversification in deep-sea organisms, using a time-calibrated molecular phylogeny of the heterobranch gastropod genus Scaphander.

LOCATION

Atlantic and Indo-West Pacific (IWP) oceans.

METHODS

Two mitochondrial gene markers (COI and 16S) and one nuclear ribosomal gene (28S) from six Atlantic species of Scaphander, and four IWP species were used to generate a multilocus phylogenetic hypothesis using uncorrelated relaxed-clock Bayesian methods implemented in beast and calibrated with the first occurrence of Scaphander in the fossil record (58.7-55.8 Ma).

RESULTS

Two main clades were supported: clade A, with sister relationships between species and subclades from the Atlantic and IWP; and clade B, with two western Atlantic sister species. Our estimates indicate that the two earliest divergences in clade A occurred between the middle Eocene and late Miocene and the most recent speciation occurred within the middle Miocene to Pleistocene. The divergence between the two western Atlantic species in clade B was estimated at late Oligocene-Pliocene.

MAIN CONCLUSIONS

The prevailing mode of speciation in Scaphander was allopatric, but one possible case of sympatric speciation was detected between two western Atlantic species. Sister relationships between IWP and Atlantic lineages suggest the occurrence both of vicariance events caused by the closure of the Tethyan Seaway and of dispersal between the two ocean basins, probably around South Africa during episodic disruptions of the deep-sea regional current system caused by glacial-interglacial cycles. Cladogenetic estimates do not support comparatively older diversification of deep-sea faunas, but corroborate the hypothesis of a pulse of diversification centred in the Oligocene and Miocene epochs. Amphi-Atlantic species were found to occur at deeper depths (bathyal-abyssal) and we hypothesize that trans-Atlantic connectivity is maintained by dispersal between neighbouring reproductive populations inhabiting the abyssal sea floor and by dispersal across the shelf and slope of Arctic and sub-Arctic regions.

Links

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Authors+Show Affiliations

Eilertsen MH

Marine Biodiversity Research Group Department of Biology University of Bergen 5006 Bergen Norway.

Malaquias MA

Phylogenetic Systematics and Evolution Research Group Department of Natural History University Museum of Bergen University of Bergen 5020 Bergen Norway.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

27524853

Citation

Eilertsen, Mari H., and Manuel António E. Malaquias. "Speciation in the Dark: Diversification and Biogeography of the Deep-sea Gastropod Genus Scaphander in the Atlantic Ocean." Journal of Biogeography, vol. 42, no. 5, 2015, pp. 843-855.

Eilertsen MH, Malaquias MA. Speciation in the dark: diversification and biogeography of the deep-sea gastropod genus Scaphander in the Atlantic Ocean. J Biogeogr. 2015;42(5):843-855.

Eilertsen, M. H., & Malaquias, M. A. (2015). Speciation in the dark: diversification and biogeography of the deep-sea gastropod genus Scaphander in the Atlantic Ocean. Journal of Biogeography, 42(5), 843-855.

Eilertsen MH, Malaquias MA. Speciation in the Dark: Diversification and Biogeography of the Deep-sea Gastropod Genus Scaphander in the Atlantic Ocean. J Biogeogr. 2015;42(5):843-855. PubMed PMID: 27524853.

* Article titles in AMA citation format should be in sentence-case

TY - JOUR T1 - Speciation in the dark: diversification and biogeography of the deep-sea gastropod genus Scaphander in the Atlantic Ocean. AU - Eilertsen,Mari H, AU - Malaquias,Manuel António E, Y1 - 2015/01/30/ PY - 2016/8/16/entrez PY - 2015/5/1/pubmed PY - 2015/5/1/medline KW - Allopatric speciation KW - Cephalaspidea KW - Heterobranchia KW - Mollusca KW - Tethyan vicariance KW - amphi‐Atlantic KW - dispersal KW - diversification pulse KW - marine biogeography SP - 843 EP - 855 JF - Journal of biogeography JO - J Biogeogr VL - 42 IS - 5 N2 - AIM: The aim of this work was to improve understanding about the mode, geography and tempo of diversification in deep-sea organisms, using a time-calibrated molecular phylogeny of the heterobranch gastropod genus Scaphander. LOCATION: Atlantic and Indo-West Pacific (IWP) oceans. METHODS: Two mitochondrial gene markers (COI and 16S) and one nuclear ribosomal gene (28S) from six Atlantic species of Scaphander, and four IWP species were used to generate a multilocus phylogenetic hypothesis using uncorrelated relaxed-clock Bayesian methods implemented in beast and calibrated with the first occurrence of Scaphander in the fossil record (58.7-55.8 Ma). RESULTS: Two main clades were supported: clade A, with sister relationships between species and subclades from the Atlantic and IWP; and clade B, with two western Atlantic sister species. Our estimates indicate that the two earliest divergences in clade A occurred between the middle Eocene and late Miocene and the most recent speciation occurred within the middle Miocene to Pleistocene. The divergence between the two western Atlantic species in clade B was estimated at late Oligocene-Pliocene. MAIN CONCLUSIONS: The prevailing mode of speciation in Scaphander was allopatric, but one possible case of sympatric speciation was detected between two western Atlantic species. Sister relationships between IWP and Atlantic lineages suggest the occurrence both of vicariance events caused by the closure of the Tethyan Seaway and of dispersal between the two ocean basins, probably around South Africa during episodic disruptions of the deep-sea regional current system caused by glacial-interglacial cycles. Cladogenetic estimates do not support comparatively older diversification of deep-sea faunas, but corroborate the hypothesis of a pulse of diversification centred in the Oligocene and Miocene epochs. Amphi-Atlantic species were found to occur at deeper depths (bathyal-abyssal) and we hypothesize that trans-Atlantic connectivity is maintained by dispersal between neighbouring reproductive populations inhabiting the abyssal sea floor and by dispersal across the shelf and slope of Arctic and sub-Arctic regions. SN - 0305-0270 UR - https://www.unboundmedicine.com/medline/citation/27524853/Speciation_in_the_dark:_diversification_and_biogeography_of_the_deep_sea_gastropod_genus_Scaphander_in_the_Atlantic_Ocean_ DB - PRIME DP - Unbound Medicine ER -

Tags

Speciation in the dark: diversification and biogeography of the deep-sea gastropod genus Scaphander in the Atlantic Ocean.J Biogeogr. 2015 May; 42(5):843-855.JB

AIM