Erylus incrustans Lehnert & Van Soest, 1999

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 85

Erylus incrustans Lehnert & Van Soest, 1999

Figs 53 a–g

Erylus incrustans Lehnert & Van Soest, 1999: 142 , figs 1–8.

Material examined. RMNH Por.9367, Guyana, ‘Luymes’ Guyana Shelf Expedition, station 107, 7.7°N 57.5°W, depth 65 m, bottom muddy sandy with shells, 5 September 1970 ; RMNH Por. 9884, Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station G56, 7.26°N 56.6667°W, depth 67–68 m, Agassiz trawl, 10 May 1966 .

Examined for comparison. Holotype ZMA Por. 13510, Jamaica, Discovery Bay, Dairy Bull, 70.1 m, 27 June 1996, coll. H. Lehnert #J96/37-1.

Description. Finger-shaped or irregularly cylindrical ( Figs 53 a), up to 3 x 1 cm. Color in alcohol pale red brown or beige. Inside the color is slightly paler. One sample (9367, Figs 53 a) consists of three fragments, the other (9884) of two, in both cases it is not clear whether the fragments are from the same specimen. Surface smooth, detachable, no apparent oscules. One of the paratype fragments shows lighter spots on the surface. Consistency rather soft.

Skeleton. The ectosomal skeleton is a thick layer of aspidasters and microrhabds, carried by the cladomes of the ortho/plagiotraenes. The choanosomal skeleton is pulpy and confused.

Spicules. ( Figs 53 b–g) Oxeas, ortho/plagiotriaenes, aspidasters, microrhabds, spheroxyasters, oxy-/ strongylasters,.

Oxeas ( Figs 53 b,b1), fusiform, occasionally strongylote, 702– 813 – 1014 x 18 – 21.7 –27 µm.

Ortho/plagiotriaenes ( Figs 53 c,c1), short-shafted, occasionally plagiodiaenes, rhabdomes 242– 371 –486 x 7 – 13.9 –21 µm, cladi 76– 141 –168 x 6 – 12.7 –18 µm.

Microrhabds ( Figs 53 d,d1), smooth, fusiform, slightly curved, faintly centrotylote, overall size 22–63 x 1.5–4.5 µm, divisible in two size classes, (1) larger ( Fig. 53 d), 44– 54.2 – 63 x 2.5– 3.4 –4.5 µm and (2) smaller ( Fig. 53 d1), 22– 33.0 – 38 x 1.5– 2.1 –3 µm.

Aspidasters ( Figs 53 e–e4), variable in shape and outline, but always thick-bladed oval with occasionally rather abrupt-squarish apices, with central, vaguely spider-like pattern of smooth areas among the dense fields of rosettes, 126– 144 –169 x 51 – 58.6 –69 µm.

Spheroxyasters ( Fig. 53 f), with smooth center, rays with large conical spines at the apices, overall diameter 13– 14.8 –17 µm, with 9– 12.3 –15 rays.

Oxyasters/strongylasters ( Fig. 53 g), with smooth center, sparingly spined cylindrical rays, at the apices slightly denser spined, overall diameter 32– 37.8 –51 µm, with 5– 5.9 –8 rays.

Distribution and ecology. Guyana Shelf, Jamaica, sandy bottom at 65–70 m depth.

Remarks. Among the many described Erylus species in the Greater Caribbean and North East Brazilian waters, the two specimens reported here are assigned to Erylus incrustans Lehnert & Van Soest, 1999 as it has almost identical aspidasters and shapes of the other spicules match closely. I compared my material with the holotype, ZMA Por. 13510, from 70 m off N Jamaica . Sizes of the oxyasters in the type are slightly smaller (32–35 µm), and the encrusting habit of the Jamaican holotype is not shared with our specimens. Both features are assumed to be subject to considerable variation. The length of the rhabds of (rare) triaenes of the type were given as 152–163 µm, but my observation of the few triaenes present in the slides made additionally for the present study is that the rhabdomes can be larger than 300 µm. This is apparently not a difference between the Guyana material and the type.

There are several Erylus species in the general region (including nearby North East Brazil) that appear close. Rather similar aspidasters are found in E. trisphaerus ( De Laubenfels, 1953) (as Unimia ), recently re-described by Ulgalde et al. 2015. The shape is, however, distinctly trilobed and also smaller in E. trisphaerus , and the aster complement of that species comprises three categories instead of two. The widespread E. formosus Sollas, 1886 has also rather similar aspidasters, but these are longer, narrower, and tapering towards both ends. E. latens Moraes & Muricy, 2007 likewise has narrow aspidasters, but these are more gradually tapering than those of E. formosus . Its aspidasters are up to 302 µm long, almost twice as long as those in the present material. It also has a third category of smooth oxyasters.

Most other Caribbean and North East Brazilian Erylus species differ clearly in having thin-bladed oval aspidasters, differing among themselves in details of euasters and other spicular details.

Figures

FIGURE 53. Erylus incrustans Lehnert & Van Soest, 1999, a, habitus of RMNH Por. 9367 (scale bar = 1 cm), b – g, SEM images of spicules, b, oxea, b 1, details of b, c, larger ortho- / plagiotriaene, c 1, shorter ortho- / plagiotriaene, d, larger microrhabd, d 1, shorter microrhabd, e, fullgrown aspidaster, e 1, squarish aspidaster, e 2, larger juvenile aspidaster, e 3, smaller juvenile aspidaster, e 4, detail of e, f, spheroxyaster, g, oxy- / strongylaster.