Kai Horst George

New species of Echinoderes (Kinorhyncha: Cyclorhagida) from Mediterranean seamounts and from the deep-sea floor in the Northeast Atlantic Ocean, including notes on two undescribed species

Two new species of Echinoderes from the Eratosthenes Seamount and a deep-sea station near the Sedlo Seamount are described. Echinoderes multiporus sp. nov. from the Eratosthenes Seamount is characterized by a combination of the presence of middorsal acicular spines on segments 4, 6, and 8, ventrolateral tubes on segment 2, lateroventral tubes on segment 5, lateroventral acicular spines on segments 6-9, midlateral tubes on segment 10, and type-2 glandular cell outlets in subdorsal position on segment 2 and in laterodorsal position on segments 4-9. Echinoderes unispinosus sp. nov. from the deep-sea station differs from its congeners by the combination of middorsal acicular spine on segment 4, lateroventral acicular spines on segments 6 and 7, type-2 glandular cell outlets present in midlateral position on segment 1, in subdorsal, laterodorsal, sublateral, and ventrolateral position on segment 2, in lateral accessory position on segment 5, and in sublateral position on segment 8, and densely aligned pectinate fringe teeth of the primary pectinate fringes similar in width on segments 1-10. In addition, the morphological data of two undescribed species from the Anaximenes Seamount and a deep-sea station near the Sedlo Seamount are given. An undescribed species from the Anaximenes Seamount is morphologically similar to Echinoderes unispinosus sp. nov., but differs in the smaller trunk length, the presence of broader pectinate fringe teeth of the primary pectinate fringe on segment 1, and the absence of ventromedial sensory spots on segment 8. Another undescribed species from the deep-sea station differs from its congeners in the pattern of spines, tubes, and type-2 glandular cell outlets and length of middorsal and lateral terminal spines. New names are not given to both undescribed species in this study, because only one specimen is available for each species, and both of the specimens were damaged during the preparation.

Echinoderes pterus sp. n. showing a geographically and bathymetrically wide distribution pattern on seamounts and on the deep-sea floor in the Arctic Ocean, Atlantic Ocean, and the Mediterranean Sea (Kinorhyncha, Cyclorhagida)

Abstract Kinorhynchs rarely show a wide distribution pattern, due to their putatively low dispersal capabilities and/or limited sampling efforts. In this study, a new kinorhynch species is described, Echinoderes pterus sp. n., which shows a geographically and bathymetrically wide distribution, occurring on the Karasik Seamount and off the Svalbard Islands (Arctic Ocean), on the Sedlo Seamount (northeast Atlantic Ocean), and on the deep-sea floor off Crete and on the Anaximenes Seamount (Mediterranean Sea), at a depth range of 675–4,403 m. The new species is characterized by a combination of middorsal acicular spines on segments 4–8, laterodorsal tubes on segment 10, lateroventral tubes on segment 5, lateroventral acicular spines on segments 6–9, tufts of long hairs rising from slits in a laterodorsal position on segment 9, truncated tergal extensions on segment 11, and the absence of any type-2 gland cell outlet. The specimens belonging to the populations from the Arctic Ocean, the Sedlo Seamount, and the Mediterranean Sea show morphological variation in the thickness and length of the spines as well as in the presence/absence of ventromedial sensory spots on segment 7. The different populations are regarded as belonging to a single species because of their overlapping variable characters.