Ute insulagemmae, Van & De, 2018

Van, Rob W. M. & De, Nicole J., 2018, Calcareous sponges of the Western Indian Ocean and Red Sea, Zootaxa 4426 (1), pp. 1-160 : 92-95

Ute insulagemmae sp.nov.

Figs 54a–e , 55a–g

Material examined. Holotype, ZMA Por. 11562, Seychelles, Amirantes, St. François Atoll, Île Bijoutier, reef, 7.0833°S 52.7333°E, depth 6–18 m, scuba, coll. R.W.M. van Soest, field nr . NIOP-E stat. 792/ 03, 5 January 1993.

Description. Twin urn-shaped individuals ( Fig. 54a ) joint at the base, with a narrow oscule each provided with a short naked collar. Color in life pale orange, in preservation shiny white. Length 1.3 cm, diameter of an individual 5 mm. Surface smooth. Consistency firm.

Aquiferous system. Syconoid.

Skeleton. ( Figs 54b–e ) A thin cortical skeleton of very small triactines ( Figs 54b,d ) forming small meshes of 50–70 µm diameter covers a subcortical layer of lengthwise arranged giant diactines ( Figs 54b–d ). This in turn overlies an articulated skeleton ( Figs. 54c,e ) of larger triactines. Subatrial skeleton of tetractines and triactines, overlying the atrial skeleton ( Fig. 54e ) of tetractines with their apical actines protruding in the atrial lumen.

Spicules. ( Figs 55a–g ) Giant diactines, cortical small triactines, tubar triactines, (sub)atrial triactines, (sub-)atrial tetractines, trichoxeas.

Giant diactines ( Fig. 55a ), fusiform, slightly curved or straight, equiended, 256– 1509 – 2520 x 13 – 68.1 –116 µm.

Cortical triactines ( Figs 55b ), sagittal, with strongly irregular paired actines and conical unpaired actines, occasionally reduced to conical tyle, unpaired actines 5– 9.4 – 18 x 2 – 4.1 –6 µm, paired actines 21– 35 – 51 x 2.5– 3.6 –4 µm.

Tubar triactines ( Figs 55c ), sagittal, but unpaired and paired actines usually not much different in lengths, paired actines straight or slightly curved, (overlapping in shape and size with subatrial triactines); possibly divisible in subcortical (larger) triactines and genuine (smaller) tubar triactines, but this was not readily visible; unpaired actines 52– 79.5 –112 x 8 – 10.2 –13 µm, paired actines 69– 85.1 –117 x 7 – 8.8 –13 µm.

Subatrial triactines ( Fig. 55d ), strongly sagittal with unpaired actines distinctly longer than paired actines; unpaired actines 91– 168 –203 x 9 – 12.4 –15 µm, paired actines 78– 97 –112 x 9 – 12.2 –14 µm.

Subatrial tetractines ( Fig. 55e ), recognizable by a long thinly tapering unpaired actine, which may occasionally have a distal swelling; unpaired actines 171–202–241 x 8 –10.2–11 µm, paired actines 76– 109 –126 x 10 – 11.3 –12 µm, apical actines curved 49– 60.4 – 71 x 6 – 7.1 –8 µm.

Atrial tetractines ( Figs 55f ), sagittal, with prominent curved apical actines; unpaired actines 61– 107.6 –165 x 7 –8.6–11 µm, paired actines 68– 104 –126 x 6 – 8.3 –10 µm, apical actines 40– 115 –201 x 6 – 8.4 –11 µm.

Trichoxeas ( Fig. 55g ), from the short oscular collar, invariably broken, fragments measure 180–650 x 2 µm.

Distribution and ecology. Known only from the type locality on the outer reef of Île Bijoutier, at 6–18 m depth.

Etymology. The name is a noun composed of insula (L.) = island, gemma (L.) = jewelry, referring to the type locality Île Bijoutier (‘jewelry island’).

Remarks. Wörheide & Hooper (2003) described Ute ampullacea from the Great Barrier Reef, NE Australia. This has similar habitus and spiculation, but the cortical skeleton consists of microdiactines, whereas in the new species these are replaced by irregular small triactines ( Fig. 55b ). We obtained molecular data for the new species and compared these with GenBank sequences of Ute and Synute . Remarkably, in our Calcaronea phylogeny ( Fig. 3 ) Ute ampullacea and our new species do not show close relationship, as the former ended up in a group of Lelapiidae . The nearest species to Ute insulagemmae sp.nov. appear to be Australian Ute aff. syconoides ( Carter, 1886) and Australian Synute pulchella ( Dendy, 1892) , which grouped in a well-supported clade (86% bootstrap value) with our new species. Separate inspection of a trimmed alignment of 404 sites of these three species, showed 19 non-conserved sites indicating that the species are probably not closely related. No other Ute species have been reported from the tropical Indo-West Pacific.

The Ute group appeared in our Calcaronea phylogeby ( Fig. 3 ) in the midst of a group of Heteropiidae and Jenkinidae . We interprete this result as evidence of insufficient taxon support for our Calcaronea phylogeny.

Figures

FIGURE 3. Maximum-likelihood tree based on analysis of sequences of the partial 28S gene (C2–D2 region, comprising 461 sites) of Western Indian Ocean Calcaronea newly generated by the Naturalis Biodiversity Center and sequences additionally obtained from GenBank, the Sponge Barcode Project and from Oliver Voigt (München) from the Red Sea, Indonesia, Australia, and a few sequences from other parts of the world, to demonstrate the affiliation of the compared species. Numbers at the root of clades are bootstrap values of 1000 replicates.

FIGURE 54. Ute insulagemmae sp.nov., holotype ZMA Por. 11562, from Île Bijoutier, Seychelles, a, preserved habitus (scale bar = 1 cm), light microscopic image of surface skeleton, c, ditto of cross section of body wall, d, enlarged view of b, showing meshes made up of cortical triactines overlying subcortical giant diactines, e, enlarged view of c showing syconoid skeleton and protruding apical actines of atrial tetractines.

FIGURE 55. Ute insulagemmae sp.nov., holotype ZMA Por. 11562, SEM images of the spicules, a, diactines, b, cortical triactines, c, tubar triactines, d, subatrial triactines, e, subatrial tetractine, f, atrial tetractines, g, broken trichoxea from the short oscular collar.