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First record of Caymanostella (Asteroidea: Caymanostellidae) from the North Pacificтезисы доклада
- Авторы: Dilman A.B., Minin K.V., Petrov N.B.
- Сборник: Abstracts of 10th European conference on Echinoderms
- Тезисы
- Год издания: 2019
- Место издания: Borissiak Paleontological Institute PAS, Moscow
- Первая страница: 17
- Последняя страница: 17
- Аннотация: The family Caymanostellidae was established by Belyaev (1974) based on 13 specimens found on sunken wood collected from the Cayman Trench, Caribbean Sea at the depths 6740-6780 m. All specimens were referred to a new species Caymanostella spinimarginata Belyaev, 1974. The genus Caymanostella currently comprises four species. Among them only C. spinimarginata is known from the Atlantic Ocean, the others are recorded from the Indian Ocean and South Pacific. Three specimens of Caymanostella were recently sampled during the joint German–Russian expedition KuramBio II from the abyssal plain adjacent to the Kuril-Kamchatka Trench at the depths 5101–5134 m. The sea stars were found on sunken wood along with other taxa associated with this special habitat. Surprisingly, these new specimens were very similar to the C. spinimarginata, the most geographically distant species. Comparison of the KuramBio II specimens and the type material of C. spinimarginata showed that they share the main morphological characters of this species: gonopore position, abactinal plate arrangement and the shape of the inferomarginal spines. However, the new specimens had more elongated abactinal spinelets and more thorny adambulacral spines. Larger size of these spines and spinelets in the KuramBio II specimens possibly reflects the size difference between them and examined specimens of C. spinimarginata. All these differences are rather point at intraspecific than interspecific variability. Multi-gene molecular data was obtained for the enigmatic family Caymanostellidae for the first time due to a good preservation of the KuramBioII specimens (only single 595 bp fragment of 16S rRNA gene was known for Caymanostella sp. up to date). Preliminary phylogenetic analyses of ribosomal COI and 16S rRNA, and nuclear 18S rRNA gene sequences (total length ~3123 bp) place caymanostellids into a basal polytomy among representatives of six orders of the class Asteroidea. Additional data from other genetic markers is needed to clarify the phylogenetic position of the family Caymanostellidae
- Добавил в систему: Петров Николай Борисович