Clathria (Thalysias) hermicola, Van, Rob W. M., Kaiser, Kirstie L. & Syoc, Robert Van, 2011

Van, Rob W. M., Kaiser, Kirstie L. & Syoc, Robert Van, 2011, Sponges from Clipperton Island, East Pacific, Zootaxa 2839, pp. 1-46 : 17-20

Clathria (Thalysias) hermicola n. sp.

( Figs 7 A–G)

Holotype. MNHN DCL 4043–A, Jean-Louis Etienne Expédition Clipperton 2005, station 19, 10 m, on dead corals, 24–01–2005, 1 specimen.

Paratype MNHN DCL 4053–A, Jean-Louis Etienne Expédition Clipperton 2005, station and depth not recorded, on dead corals, 1 specimen.

Paratype MNHN DCL 4054–A, Jean-Louis Etienne Expédition Clipperton 2005, station 8, 15 m, on dead corals, 14–01–2005, 1 specimen.

Description. Thin (<1 mm) encrustation on undersides of corals ( Fig. 7 A), with microhispid surface, pale orange in alcohol (possibly bright red in life), lateral size indefinite, at least several cm. Consistency soft.

Skeleton. Small groups of larger styles and smaller acanthostyles are pendicular to the substratum, embedded with their heads in the spongin plate covering the substrate (microcionid structure). The ectosomal megascleres comprise two categories of subtylostyles which form loose bouquets, not a closed palisade.

Spicules. Choanosomal styles, ectosomal subtylostyles, acanthostyles, toxas, palmate isochelae.

Styles ( Fig. 7 B), shaft smooth, swollen in the mid-section, with narrow smooth or microspined heads, 126–430 x 4–8 µm

Ectosomal subtylostyles, with microspined heads, in two distinct size categories, (1, Fig. 7 C) 297– 343.5 –396 x 3 – 3.35 –4 µm, (2, Fig. 7 D) 177– 183.8 –189 x 1.5–2 µm.

Acanthostyles ( Fig. 7 E), with barely developed head and overall low degree of spination, but more heavily spined in the lower half, 67– 86.8 – 98 x 1.5– 4.3 –6 µm.

Toxas ( Fig. 7 F), fairly robust, with shallow curve (‘oxhorn’- type), in a large overlapping size range, but not divisible in categories, 13– 45.9 –64 µm.

Isochelae ( Fig. 7 G) of normal shape, with slightly thickened shaft and relatively sparsely cut alae, 12– 13.9 –15 µm.

Etymology. Herma (Gr.) = mound or coral reef, -cola = inhabiting, referring to the habit of encrusting corals in shallow reef environment.

Ecology. On the underside of dead corals, 10– 15 m.

Remarks. The new species is assigned to the subgenus Thalysias because it has two distinct size categories of ectosomal subtylostyles arranged in bouquets at the surface. Possibly the widespread Central Pacific Clathria (Thalysias) eurypa ( De Laubenfels, 1954a as Dictyociona ) is close to our new species in spicule sizes and shapes, but three features are distinctly different from the original description: there are apparently no echinating acanthostyles in C. (T.) eurypa . Subsequent records by Bergquist (1965), Kelly-Borges & Bergquist (1988) (both as Microciona ) and Pulitzer-Finali (1996) described these for this species, if correct. The larger ectosomal subtylostyles and the choanosomal styles are apparently not distinct, and there is a second category of tiny isochelae of approx. 4 µm. The latter feature is also described for Clathria (Thalysias) coralliophila ( Thiele, 1903 as Rhaphidophlus ) from Ternate (see review of specimens in Hooper, 1996). There is an outside possibility that C.(T.) eurypa is a junior synonym C. (T.) coralliophila , but the difference with our material in the possession of a second category of very small isochelae remains a clear distinction.

On paper the new species looks similar to Clathria (Microciona) plinthina ( De Laubenfels, 1954a as Microciona ) from the Central West Pacific, but this species has raphides and lacks a smaller category of subtylostyles. Resemblance is also apparent to West Pacific Clathria (Thalysias) linda ( De Laubenfels, 1954a as Axocielita ), but no echinating acanthostyles were recorded and the differentiation of the megascleres, which have prominent heads (‘tylostyles’) in ectosomal subtylostyles and choanosomal styles is apparently not present, so its assignment to the subgenus Thalysias may not be warranted. Another remote possibility is the material from Hawaii from deep water (200 m) that De Laubenfels (1957) described as Microciona haematodes , assigned to Clathria (Microciona) by Hooper (1996); the description is quite vague, and the author suggests there are no proper toxas.

Other thinly encrusting species from the Central and West Pacific are likewise clearly dissimilar to our new species: Clathria (Thalysias) longitoxa ( Hentschel, 1912 as Hymeraphia ) from the Arafura Sea has raphide-like toxas of 800 µm. Clathria (Thalysias) toxifera and Clathria (Thalysias) calochela (both described by Hentschel, 1912 as Hymeraphia ) also from the Arafura Sea have chelae twice as long as those of the Clipperton material including two size classes of toxas, plus overall spicules are considerable thicker. Clathria (Microciona) placenta ( De Laubenfels, 1954a as Microciona ) and Clathria (Microciona) lajorei ( De Laubenfels, 1954a as Anaata ), both from the Central Pacific, lack toxas. Clathria (Microciona) mima ( De Laubenfels, 1954a as Ophlitaspongia ) likewise from the Central Pacific lacks chelae. Clathria (Thalysias) maunaloa ( De Laubenfels, 1951 as Microciona ) from Hawaii has tiny chelae of 5–6 µm and much longer toxas (up to 132 µm) with a short shallow curve in the middle and straight ends. Clathria (Thalysias) kilauea ( De Laubenfels, 1951 as Axocielita ) lacks echinating acanthostyles and has C shaped chelae with reduced alae. Clathria (Microciona) micronesia ( De Laubenfels, 1954a as Microciona ) has very large, deeply curved toxas of 170 µm, and lacks a second category of ectosomal subtylostyles. Clathria (Microciona) spinatoxa ( Hoshino, 1981 as Microciona ) from Japan has toxas with spined endings. Clathria (Thalysias) naikaiensis ( Hoshino, 1981 as Eurypon ) lacks both toxas and chelae. Clathria (Thalysias) tingens Hooper, 1996 has the sizes of the echinating acanthostyles and the toxas twice that of the new species. Clathria (Thalysias) hallmanni Hooper, 1996 is essentially similar to our new species but differs sharply by the shape and the size of the ‘accolada’- type toxas.

Very few encrusting microcionids have been reported from the tropical East Pacific coasts, and no matching descriptions from that area are apparent. Northern California has several species, but none of these appear similar: Clathria (Microciona) microjoanna ( De Laubenfels, 1930 as Microciona ) has the overall spiculation like our new species, but this is a thickly encrusting (2 cm) compact sponge, with the main styles much thicker and shorter (approx. 300 x 20–27 µm) and entirely smooth, without the subterminal constriction found in the Clipperton species. Toxas are twice as long and the chelae include peculiar reduced C shapes. Clathria (Microciona) parthena ( De Laubenfels, 1930 as Microciona ) is likewise much thicker in shape, has much thicker smooth styles and chelae twice as large. Clathria (Wlisonella) pseudonapya ( De Laubenfels, 1930 as Clathriopsamma ) lacks chelae and has microxeas. Clathria (Microciona) pennata ( Lambe, 1895 as Desmacella ) lacks chelae and acanthostyles.

To facilitate comparison of closely similar species, the thinly encrusting Clathria (Thalysias) species of the warmer waters of the Pacific are summarized in Table 4 .

Figures

FIGURE 7. Clathria (Thalysias) hermicola n. sp., holotype MNHN DCL 4043 – A. A. habit, thinly encrusting on dead corals, B. choanosomal styles with smooth and microspined heads, C. subectosomal subtylostyle with microspined head, D. ectosomal subtylostyle with microspined head, E. echinating acanthostyle with relatively lightly spined upper half, F. oxhorn-like tox, G. palmate isochela.

Tables

TABLE 4. Thinly encrusting Clathria (Thalysias) species recorded from the warmer waters of the Pacific.

Name	ectosomal sub- tylostyles (I) (µm)	ectosomal sub- tylostyles (II) µm	choanosomal styles (µm)	echinating acanthostyles (µm)	toxas µm)	isochelae (µm)	Locality
C. (T.) hermicola n. sp.	297–396 x 3–4	177–189 x 1.5–2	126–430 x 4–8	67–98 x 1.5–6	13–64	12–15	Île Clipperton
C. (T.) eurypa (De Laubenfels, 1954a)	290 x 6	115 x 4	not recorded	not recorded	30–54	(I) 4, (II) 19	Palau
C. (T.) eurypa sensu Bergquist, 1965	237–490 x 7.5–13	112–200 x 3.5–5	not recorded	80–106 x 4– 6.5	36–181	(I) 3.5–5 (II) 13.5– 18	Palau
C. (T.) eurypa sensu Kelly Borges & Bergquist, 1988	267-495 x 2.5- 9	91-163 x 2.5-9	not recorded	87-113 x 6- 12.5	(I) 30-90 (II) 190- 210	(I) 12.5- 20 (II) 3-5.5	Papua New Guinea
C. (T.) eurypa sensu Pulitzer- Finali, 1996	270–430 x 7– 9.5	96–260 x 2–5	not recorded	60–81 x 7–9	35–180	7–20	Bismarck Sea
C. (T.) corallio- phila (Thiele, 1903)	213–488 x 3– 9	102–206 x 2–5	145–350 x 7– 15	48–95 x 2–5	18–244 x	(I) 2–8 (II)11–17	Indonesia, Great Barrier Reef
C. (T.) linda (De Laubenfels, 1954a)	400 x 2–3	200 x 2–3	435 x 9	not recorded	(I) 15–33, (II) 55–80	12–20	Chuk, Central Pacific
C. (T.) longitoxa (Hentschel, 1912)	432–584 x 4–9	240–408 x 13– 15	592–840 x 22– 26	64–80 x 6–7	400–800	12–13	Indonesia
C. (T.) calochela (Hentschel, 1912)	376–480 x 3–5	376–480 x 3–5	304–824 9–13	88–104 x 5	(I) 56–64 (II) 120– 160	19–21	Indonesia
C. (T.) toxifera (Hentschel, 1912)	228–494 x 2– 13	123–229 x 1.5–6.5	194–685 x 5– 25	122–208 x 3– 14	16–241	10–30	Indonesia, Australia
C. (T.) maunaloa (De Laubenfels, 1951)	240 x 9	120–160 x 6	425 x 13	42 x 8	56–132	14	Hawaii
C. (T.) kilauea (De Laubenfels, 1951)	280 x 12	144 x 2	630 x 15	not recorded	30–60	14	Hawaii
C. (T.) tingens Hooper, 1996	259–502 x 4.5–10.5	118–208 x 2– 5.5	198–524 x 9– 19	80–151 x 4.5– 12.5	37–342	10–20	Great Barrier Reef
C. (T.) hallmani Hooper, 1996	284–450 x 2– 4.5	94–151 x 0.8– 2.5	312–419.5 x 8–11	52–72 x 3–6.5	174–481	5–17	North Austra- lia
Clathria (Thaly- sias) naikaiensis (Hoshino, 1981)	up to 385 x 8	as small as 185 x 3	145–362 x 9– 12	58–65 x 4–7	not recorded	not recorded	Japan