Sphenopus pedunculatus Hertwig, 1888

Reimer, James D., Poliseno, Angelo & Hoeksema, Bert W., 2014, Shallow-water zoantharians (Cnidaria, Hexacorallia) from the Central Indo-Pacific, ZooKeys 444, pp. 1-57 : 13-14

Taxon classification Animalia Zoantharia Sphenopidae

12. Sphenopus pedunculatus Hertwig, 1888 Figures 10C, D, 11

Specimens examined

(n=2). RMNH Coel 40507, Kepulauan Seribu Expedition station SER.29, north side of Pulau Tikus, Thousand Islands off Jakarta, northwest Java (05°51'13"S, 106°34'43"E), depth = 30 m, collected on September 18, 2005 by B.W. Hoeksema; RMNH Coel 40510, East Kalimantan–Berau Expedition station BER.03, south side of Pulau Derawan, East Kalimantan (02°17'03"N, 118°14'49"E), depth = 15 m, collected on October 21, 2003 by B.W. Hoeksema.

Photographic records

(n=2). Images of RMNH Coel. 40507 and RMNH Coel 40510 as above.

Description.

This azooxanthellate species was originally described from the Philippines, and has not been reported in the literature for over 80 years, excepting two brief mentions in Reimer et al. (2012b). Easily discernable from other Sphenopus species by the presence of a ‘foot’ (=peduncle) that is attached to substrate (e.g. small rocks).

The two specimens here varied in length from 33 to 62 mm in polyp length, and had a width between 9 to 11 mm (polyp head). The “swollen”, non-peduncle part of the polyp was between 15 to 20 mm in height, with the remainder of the length made up of the peduncle, which was between 0.5 to 3 mm in width. RMNH Coel 40507 polyps were generally smooth in appearance, while the upper portions of polyps of RMNH Coel 40510 were somewhat rugged, with small round tubercules 0.5 mm in diameter roughly arranged in vertical lines. The spaces between these small tubercules were colored a much darker color than the remainder of the polyps’ outer surfaces. The peduncle of specimens and images (Figure 10C) are much thinner and longer than the sketch in Hertwig (1888). However, so few data are available for this (and other Sphenopus species) that currently nothing is known about intraspecific variation, and for now, we group these two specimens within this species.

Distribution.

Regions recorded in this study (Figure 11). Northwest Java (3), Berau Islands (19).

Previous records. This species was originally described from the Philippines, but has not been mentioned in recent literature (except for Reimer et al. 2012b), and hence very little is known on its distribution or ecology.

Remarks.

It is unknown as to whether the peduncle is a morphological characteristic that forms only when there is a hard substrate available, and this needs to be investigated to confirm this is truly a different species from Sphenopus marsupialis .