Holanthus expergitus

Holanthus expergitus (Loven, 1871). AphialD: 526627. New record. (Fig. 4 a–c). Material examined. One preserved specimen with catalogue number (station included): 526627-B76 (B11 V 02). Description. Test outline oval in aboral view (Fig. 4a, b). Apical system ethmophract (posterior genital and ocular plates not separated by the madreporite) with four gonopores (Fig. 4a). Presence of a peripetalous fasciole positioned adapically far above the ambitus in the anterior of the test (Fig. 4a). Anal and subanal fascioles absent (Fig 4b). Petals short, posterior ones only half the size of anterior ones. Oral side flat with peristome anterior in position. Short sternum as wide as long. Distribution. Atlantic Ocean, United Kingdom, Ireland, south Iceland, Bay of Biscay, southwest of Portugal, Azores, Labrador Sea, east of North America from Massachusetts to North of Carolina, Gulf of Mexico, Caribbean Sea, Pacific Ocean, east and south of Japan, Indonesia, Philippine Sea, Sulu Sea, Makassar Strait, Flores Sea, Tasman Sea, southeast of Australia, New Zealand. (Loven, 1871; Mortensen 1927; Schultz, 2009; Kroh, & Mooi, 2022; OBIS, 2022) Bathymetric range. 320 m (USNM E 41727)– 4897 m (Mironov, 2014). Present study: 1706 m. Remarks. Five extant species of the genus Holanthus Lambert & Thiéry, 1924 are known to date. Two of them are close morphologically, H. expergitus and H. tenuis (A. Agassiz, 1898). In H. expergitus, the shape of the test is oval, and the anterior petals are twice as long as the posterior ones. In H. tenuis, the test is more rounded, and the sternum is long and narrow, much longer than wide. The two species have very distinct distributions (Fig. 4).