Trissopathes, Opresko, 2003

Lima, Manuela M., Cordeiro, Ralf T. S. & Perez, Carlos D., 2019, Black Corals (Anthozoa: Antipatharia) from the Southwestern Atlantic, Zootaxa 4692 (1), pp. 1-67 : 17-19

Trissopathes sp.

Fig. 7 , 9

Material examined. ERG –078, SA–MAR ECO / Marion Dufresni Cruise , circular dredge, Rio Grande Rise, 30º16’29.28”S, 36º25’10.2”W; 1200–1300 m, date: 22/06/2011 ( MNRJ 8596 , six fragments) .

Description of Brazilian specimens. Six fragments, branched to the 3rd order, with pinnulation damaged ( Fig. 7a ). Larger fragment 21.20 cm long, with stem 3.67 mm thick. Pinnules in four rows, two posterior/laterals and two anterior, in a density of 15 per centimeter. Anterior rows very close to each other, appearing to form a single row. Length of lateral pinnules mostly 7–11 mm, but up to 22 mm, inclined towards the distal end (50°–80°) ( Fig. 7b ). Length of anterior primary pinnules mostly between 5 and 9 mm, sometimes reaching 15 mm. Basal diameter of lateral pinnules 0.1–0.3 mm. Distance between cycles of lateral pinnules 1.5–2 mm. Subpinnules occurring in number of two to five per primary anterior pinnule, arranged in subopposition, rarely alternate. Tertiary pinnules absent in all fragments. Insertion of secondary pinnules on anterior primary pinnules in angles between 80° and 120°. Secondary pinnules up to 23 mm, especially the most proximal pair. Spines conical, inclined upwards the tips of the pinnule, arranged in three to four longitudinal rows, visible in lateral view ( Fig. 7 c–d). No distinction between polypar and abpolypar spines, sometimes very small (<0.017 mm) or absent, and adjacent spines in the same row can be of different sizes. Size of spines on anterior pinnules 0.019–0.05 mm; size of spines on secondary pinnules 0.019 –0.038 mm; size of spines on lateral pinnules 0.017 –0.048 mm. Distance between spines in a same row usually 1 mm on secondary pinnules; 0.6–0.7 mm on anterior pinnules; and 0.60–1.14 mm on lateral pinnules. Base of spines 0.09–0.20 mm thick. Polyps not visualized (lost tissue).

Remarks. Trissopathes sp. differs from Trisopathes tetracrada Opresko, 2003 and Trissopathes pseudotristicha Opresko, 2003 mainly in subpinnulation pattern. Trissopathes tetracrada has sparse subpinnules (usually one subpinnule per anterior primary pinnule, varying between 0 and 2), in contrast with 2–6 subpinnules in Trissopathes sp.. Similarly, T. pseudotristicha shows a single pair of subpinnules per anterior primary. Trissopathes tristicha has the most dense subpinnulation pattern within the genus, with more than six secondary pinnules per anterior primary ( Opresko, 2003). Both T. tristicha and Trissopathes sp. have the rows of anterior pinnules aligned very close to each other, appearing to form a single row. However, the latter shows longer anterior pinnules (15 mm) on the median portion of older branches, occasionally longer than the lateral pinnules. Longer anterior pinnules were also described by Opresko (2003) in specimens of T. tristicha from the Philippines. But the specimen described here also differs from T. tristicha by having smaller spines (0.20–0.28 mm in T. tristicha , and 0.017–0.05 mm herein). The shape of the spines in Trissopathes sp. is also less acicular than those in T. tristicha , and more similar to those of T. tetracrada . However, the state of the specimen studied here, with damaged pinnules, fractured stem and absence of polyps prevents the description of a new species for this material. Additional studies and more specimens collected from the region are needed to clarify whether the observed characteristics correspond to differences with taxonomic significance or whether they represents intraspecific variation. This is the first record of the genus Trissopathes in the southwestern Atlantic ( Fig. 9 ).

Figures

FIGURE 7. MNRJ 8596: Trissopathes sp. a—Corallum morphology; b—Pinnulation pattern; c—Organization of spines; d— Spines magnified.

FIGURE 9. Geographic distribution of Genus Trissopathes Opresko, 2003. Yellow circles: records extracted from the literature (Opresko, 2003) and based on Ocean Biogeographic Information System (OBIS). Red circle: record made in the present work.