Amphianthus michaelsarsi Carlgren, 1934

Amphianthus michaelsarsi Carlgren, 1934 View in CoL

( Fig. 4 View FIGURE 4 ; Table 4)

MATERIAL EXAMINED. MNRJ 9083 View Materials (six specimens), South Atlantic Ocean , Potiguar Basin , Rio Grande do Norte, Brazil, station MT85 (04° 21.3580'S, 036° 44.2730’W), May 8, 2011, 2057 m. GoogleMaps MOUFPE-CNI 876 (ten specimens) South Atlantic Ocean , Potiguar Basin, Rio Grande do Norte, Brazil, station MT63 (04° 41.7490’S, 036° 31.1670’W), May 8, 2011, 375 m. GoogleMaps LC 160 (one specimen) South Atlantic Ocean , Potiguar Basin, Rio Grande do Norte, Brazil, station MT63 (04° 41.7490’S, 036° 31.1670’W), May 8, 2011, 375 m. GoogleMaps LC 161 (seven specimens) South Atlantic Ocean, Potiguar Basin, Rio Grande do Norte, Brazil, station MT85 (04° 21.3580’S, 036° 036° 44.2730’W), May 4, 2011, 2057 m GoogleMaps .

SHORT DESCRIPTION. Small individuals, 3 to 9 mm in height and 4 to 11 mm in diameter. Body short, flat, or globose with 24 rows of small tubercles. Around 70 tentacles, relatively long, in four alternating cycles. Up to two cinclides, each one associated with a directive endocoels. Mesenteries irregularly arranged in four cycles, more numerous at base than at margin. Acontia not numerous.

CNIDOM. Spirocysts, basitrichs, holotrichs, and microbasic p -mastigophores B1 ( Fig. 4I View FIGURE 4 : f–j, Table 4).

GEOGRAPHIC DISTRIBUTION. Amphianthus michaelsarsi is known only from its type material, ten individuals from the Michael Sars Expedition (1910), studied by Carlgren (1934), and from Molodtsova et al. (2008), both from the Mid-Atlantic Ridge in the North Atlantic. The present work expands its geographical distribution to the South Atlantic (Potiguar basin, RN, Brazil).

REMARKS. The morphological investigation of A. michaelsarsi from Potiguar Basin matches the description from North Atlantic surveys made by Carlgren (1934), with minor differences in cnidom. Carlgren (1934) does not differentiate the nematocysts of the mesenterial filaments, which we observed to be basitrichs and microbasic p -mastigophores B1. We found holotrichs in the tentacles and some slightly larger basitrichs in the acontia of our individuals not reported by Carlgren (1934).