Dietz, L.; Krapp, F.; Hendrickx, M. E.; Arango, C. P.; Krabbe, K.; Spaak, J. M.; Leese, F. (2013). Evidence from morphological and genetic data confirms that Colossendeis tenera Hilton, 1943 (Arthropoda: Pycnogonida), does not belong to the Colossendeis megalonyx Hoek, 1881 complex. Organisms Diversity & Evolution. 13(2): 151-162.
Dietz, L.; Krapp, F.; Hendrickx, M. E.; Arango, C. P.; Krabbe, K.; Spaak, J. M.; Leese, F.
2013
Evidence from morphological and genetic data confirms that Colossendeis tenera Hilton, 1943 (Arthropoda: Pycnogonida), does not belong to the Colossendeis megalonyx Hoek, 1881 complex
Organisms Diversity & Evolution
13(2): 151-162
Publication
Within the Pycnogonida, genetic studies have
revealed that Colossendeis megalonyx Hoek (Challenger
Report, Zoology, 3(X), 1–167, 1881), consists of a complex of
several cryptic or overlooked species. Colossendeis megalonyx
is a typical Southern Hemisphere species complex distributed
primarily on the continental shelves in the Antarctic and
Subantarctic. However, a different Colossendeis species
with a completely different geographic distribution range,
Colossendeis tenera Hilton (Journal of Entomology and
Zoology, Pomona College, Claremont, 35(1), 2–4, 1943), was
considered a subspecies of Colossendeis megalonyx by Turpaeva
(Trudy Instituta Okeanology "P. P. Shirshova", Akademy Nauk
SSSR, 103, 230–246, 1975). Colossendeis tenera occurs predominantly
along the Pacific Coast of North America from the
Bering Sea to central California. Prominent differences between
these two currently distinct species are found in body proportions
and other characters that were interpreted by Turpaeva as a
possible case of pedomorphosis induced by deep-sea conditions.
In this study, we tested the hypothesis that Colossendeis tenera
belongs to the Colossendeis megalonyx complex by analyzing
available and novel sequence data (CO1 and H3) of both
Colossendeis megalonyx and Colossendeis tenera as well as a
similar, apparently closely related species, Colossendeis angusta
Sars (Archiv for Mathematik og Naturvidenskab, 2, 237–271,
1877).We compared morphometric data and SEM of the ovigera
of these species. Our results clearly indicate that Colossendeis
tenera and Colossendeis angusta are not a part of the
Colossendeis megalonyx complex. A sister-group relationship
of Colossendeis tenera and Colossendeis angusta is strongly
supported, but Colossendeis tenera is not clearly resolved as
monophyletic with respect to Colossendeis angusta. This work
highlights the need for further examination of the variation found
in the tenera-angusta clade. It also gives a first hint of the
phylogenetic affinities of species within Colossendeis.
Southern Ocean: Antarctic and Subantarctic marine regions together (= E+W+S+M(+T))