Agelas repens Lehnert

Parra-Velandia, Fernando J., Zea, Sven & Van Soest, Rob W. M., 2014, Reef sponges of the genus Agelas (Porifera: Demospongiae) from the Greater Caribbean, Zootaxa 3794 (3), pp. 301-343 : 324-325

Agelas repens Lehnert & van Soest, 1998

Fig. 9

Etymology from Latin, meaning to creep, to crawl.

Agelas repens Lehnert & van Soest, 1998: 83, Fig. 12 .

Material and distribution. Holotype examined at the Zoölogisch Museum Amsterdam ( ZMA – POR 12870), collected at reefs in front of the mouth of Río Bueno, Jamaica, on the ceiling of a cave, 23 m depth. The material reviewed here includes only specimens from Jamaica also collected at the type locality (INV– POR 1012, 1013, 1014).

This species seems restricted to Jamaica, so we consider this as a Greater Antilles species, but see remarks. Our specimens were found from 22 to 25 m in depth, abundant at 23– 25 m.

Description. This species has a thin cord-like form ( Fig 9 A), sometimes found solitary ( Fig 9 B), branched or irregularly repent. The body hangs from a fleshy, patchy base, encrusted on walls and overhangs. Branches are up to 0.5 cm in diameter and 30–50 cm long; the base is up to 5 cm by 8 cm and 0.8 cm thick. Its external colour is spectrum orange, internal colour orange yellow. It is compressible, flexible and elastic in life or preserved, still flexible when dry.

Oscules are tiny, almost invisible to the naked eye (<2 mm), surrounded by a star-like area where exhalant channels lead to them. Pinacoderm supported by tracts of spicules, collapses out of the water revealing a rough outline of subdermal channels (<1 mm) and other structures. Choanosome is apparently dense.

Skeleton of cored (2–7 spicules per cross section) primary fibres, loosely echinated, 20–50 Μm in diameter. When the coring spicules are absent fibres are hardly distinguishable; secondary fibres 20–30 Μm in diameter, poorly echinated; no tertiaries present. Acanthostyles are straight and long with 5–6 spines per whorl; length 88–268 (180±46.1) µm, width 3–13 (8±2.1) µm and 9–23 (16±4.1) whorls per spicule. Detailed lengths, widths and average number of whorls are shown in Table 2.

Remarks. Agelas repens is found hanging from walls on caves like long and thin cords. As far as we have explored, Rio Bueno is the only locality where this species is present. Lehnert & van Soest (1998) noted that this species is rather similar to some deep, thin specimens of A. sceptrum from Barbados (ZMA–POR 3811, 100 m). Our specimens of A. sceptrum from Rosario Islands and San Andres Island are the ones most similar to A. repens . The differences in skeletal and spicule architecture and size are not enough to decide whether they are the same species, but the cryptic habit (or depth preference) and the resemblance in external morphology in A. repens and Belizean, Colombian and Barbadian A. sceptrum vs. the exposed habitat and thickly branched habit of typical A. sceptrum from Jamaica calls for synonymy. ITS and CO1 DNA analyses also placed A. repens together with A. sceptrum , but this is inconclusive as these species were also indistinguishable from A. dilatata , A. conifera , A. tubulata and A. cerebrum ( Parra-Velandia 2011) . However Jamaican A. repens were never thicker than 1 cm, while Southern Caribbean A. sceptrum were rarely this thin.

Additionally, at the type locality we noted that the external colour and tissue texture of A. repens were very similar to those of A. citrina living nearby. We then had the idea that A. repens cords may be dispersive bodies of A. citrina . This hypothesis was reinforced by the fact that A. repens spicules in Jamaica were even longer that those of A. citrina , which usually has the longest spicules of all Agelas in several localities ( Table 2). At any rate, the hypothesis of close relatedness between A. repens and A. citrina was discarded in the light of DNA studies (Parra- Velandia, 2011)

Figures

FIGURE 9. Photographs of Agelas repens from Jamaica. A) Dry Holotype at ZMA. B) in situ, hanging from the wall of a reef slope crevice. C) Several freshly collected specimens; the scale represents 20 cm length and 0, 5 cm width.

FIGURE 12. Photographs of Agelas schmidti. A) Small round, tapered finger from Belize. B) Minute open tubes from Rosario Islands, Colombia. C) Fouled finger, the Bahamas (center only). D and E) Holotype at USNM (courtesy of K. Ruetzler and C. Dietrich).