Introgression or low molecular differentiation? The case of Carabus maacki

Authors

  • Dietrich Mossakowski

Abstract

Abstract

Background: Carabus (Limnocarabus) maacki aquatilis and C. (Euleptocarabus) porrecticollis of the Japanese Island Honshu reveal a remarkably low sequence difference in the mitochondrial ND5 gene, similar to that existing between the subspecies of C. porrecticollis although the morphology is quite different. On the other hand C. maacki aquatilis from Japan is quite distinct to European C. clatratus in ND5 sequences and that was the reason to established C. maacki as a separate species, formerly a subspecies of C. clatratus. My hypothesis is that data on these taxa are better interpreted by assuming that C. maacki is in fact a C. clatratus but suffered in its Japanese form aquatilis an introgression from C. porrecticollis.

Material and Methods: Twenty-one specimens were sequenced and seven sequences were retrieved from GenBank. They comprise C. porrecticollis and C. maacki aquatilis form Japan, C. maacki maacki from the Asian mainland, and C. clatratus from Far East and Europe. The data were analysed using the maximum likelihood method and were presented as a tree and as visualisation of sequences differences.

Results: The hypothesis that C. maacki is a C. clatratus but suffered an introgression by C. porrecticollis is supported by the results because (i) C. maacki maacki from Russian Primorje clustered with Far East and European C. clatratus in mitochondrial ND5 sequences, and (ii) Japanese C. maacki aquatilis clustered with C. clatratus in the nuclear gene data of wingless, but both differ in the same way to C. porrecticollis.

Conclusions: The presented data corroborate the hypothesis of an introgression from C. porrecticollis to the population of C. maacki aquatilis on Honshu, Japan. The taxon maacki cannot maintain species status. Its two subspecies should be considered as subspecies of C. clatratus (C. clatratus maacki from the Asian mainland, C. clatratus aquatilis from Japan).

Key words: introgression, Carabus clatratus, Carabus maacki, Carabus porrecticollis

Author Biography

Dietrich Mossakowski

Institute for Ecology and Evolutionary Biology

University of Bremen

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Published

2016-12-01

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Articles