TY - JOUR
T1 - Stygobiont polychaetes
T2 - Notes on the morphology and the origins of groundwater Namanereis (Annelida: Nereididae: Namanereidinae), with a description of two new species
AU - Glasby, Chris
AU - Fiege, Dieter
AU - Van Damme, Kay
PY - 2014/5
Y1 - 2014/5
N2 - More than half of the species in NamanereisChamberlin, 1919 (Nereididae: Namanereidinae), are adapted to life in subterranean waters. We document the taxonomy, distribution, and adaptations of the groundwater-inhabiting species in this genus for the first time, starting from the description of two new stygobitic species. The first, Namanereis pilbarensis sp. nov. from water-table carbonate deposits in the Pilbara region of north-west Australia, is representing the first record of a stygobitic polychaete from Australia, and the second, Namanereis socotrensis sp. nov., from karstic groundwater on Socotra Island (Yemen) is the second stygobitic Namanereis species from Socotra. Troglomorphic adaptations observed include the absence (or reduction) of eyes and cuticular pigment, and cirriform appendages of the head, parapodia, and pygidium that are all considerably longer than in their marine counterparts. The chaetae and jaws differ in some groundwater species but not others, so the troglomorphic nature of these features is less certain. Remarkably, the two species of the Socotra Archipelago (Namanereis gesaeFiege & Van Damme, 2002, from Abd al Kuri and the new species) seem to derive from different ancestors, respectively single terminal tooth and bifid tooth-jawed lineages. Based on the jaw morphologies, we suggest that the groundwater polychaetes of this genus might not have entered groundwater from freshwater/anchialine habitats during a single colonization event, as previously suggested, but at different times. Different geographical origins of two groups of species (Gondwanan and Tethyan) are suggested based on recent distribution patterns.
AB - More than half of the species in NamanereisChamberlin, 1919 (Nereididae: Namanereidinae), are adapted to life in subterranean waters. We document the taxonomy, distribution, and adaptations of the groundwater-inhabiting species in this genus for the first time, starting from the description of two new stygobitic species. The first, Namanereis pilbarensis sp. nov. from water-table carbonate deposits in the Pilbara region of north-west Australia, is representing the first record of a stygobitic polychaete from Australia, and the second, Namanereis socotrensis sp. nov., from karstic groundwater on Socotra Island (Yemen) is the second stygobitic Namanereis species from Socotra. Troglomorphic adaptations observed include the absence (or reduction) of eyes and cuticular pigment, and cirriform appendages of the head, parapodia, and pygidium that are all considerably longer than in their marine counterparts. The chaetae and jaws differ in some groundwater species but not others, so the troglomorphic nature of these features is less certain. Remarkably, the two species of the Socotra Archipelago (Namanereis gesaeFiege & Van Damme, 2002, from Abd al Kuri and the new species) seem to derive from different ancestors, respectively single terminal tooth and bifid tooth-jawed lineages. Based on the jaw morphologies, we suggest that the groundwater polychaetes of this genus might not have entered groundwater from freshwater/anchialine habitats during a single colonization event, as previously suggested, but at different times. Different geographical origins of two groups of species (Gondwanan and Tethyan) are suggested based on recent distribution patterns.
KW - Hyporheic
KW - Pilbara
KW - Polychaete
KW - Socotra Archipelago
KW - Taxonomy
KW - Troglomorph
UR - http://www.scopus.com/inward/record.url?scp=84899523677&partnerID=8YFLogxK
U2 - 10.1111/zoj.12130
DO - 10.1111/zoj.12130
M3 - Article
VL - 171
SP - 22
EP - 37
JO - Zoological Journal of the Linnean Society
JF - Zoological Journal of the Linnean Society
SN - 0024-4082
IS - 1
ER -