Different habitat salinity between genetically divergent groups of a worm-like goby Luciogobius guttatus: an indication of cryptic species

Autor: Kotaro Takai, Seiya Hashimoto, Itsuro Koizumi, Seigo Higashi
Rok vydání: 2013
Předmět:
Zdroj: Environmental Biology of Fishes. 97:1169-1177
ISSN: 1573-5133
0378-1909
DOI: 10.1007/s10641-013-0206-7
Popis: Gobies of the genus Luciogobius have unusual morphological adaptations to interstitial rocky coastal habitats in far eastern Asia; an elongated scale-less body, the loss the first dorsal fin, and a drastically increased number of vertebrae. Convergent evolution makes the species distinction difficult and the existence of many cryptic species has been postulated. Two divergent lineages of L. guttatus had been reported with the possibility of niche differentiation between marine and brackish habitats. Here, we quantitatively assessed the water salinity of the habitats used by the two lineages in Hokkaido, Japan, as well as their morphology. One lineage occurred exclusively in high-salinity habitats in intertidal zones (> 25 aEuro degrees) and the other occurred mostly, but not exclusively, in low-salinity habitats near river mouths (< 5 aEuro degrees). This result, together with mtDNA molecular phylogeny, suggests that the brackish type might have originated from a marine ancestor. Two lineages occurred sympatrically on some shores. No apparent difference was observed in the external morphology between the lineages, whereas the number of vertebrae was significantly different. Our results support the preposition that the divergent lineages within L. guttatus represent cryptic species.
Databáze: OpenAIRE
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