Lophocalyx topsenti Janussen & Reiswig, 2009, n. sp.
Creators: name: Janussen, Dorte
name: Reiswig, Henry M.
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Porifera
Hexactinellida
Lyssacinosida
Rossellidae
Lophocalyx
Lophocalyx topsenti

description: Lophocalyx topsenti n. sp.
(Figs. 6 & 7, Table 3)
Material examined: Lophocalyx topsenti n. sp., Holotype, SMF 10606, ANDEEP III Exped., R.V. 'Polarstern', stn PS67/142-6, Weddell Sea, Antarctica, 18 Mar. 2005, 62°09.93'S, 49°30.47'W to 62°09.80'S, 49°30.59'W, 3403–3404 m, ethanol. Paratype: RSM 1921.143.1389, Scottish National Antarctic Exped., R.V. 'Scotia', stn 313, Weddell Sea, Antarctica, 18 Mar. 1903, 62°10'S, 41°20'W, 3247 m, ethanol (reported as Calycosoma validum by Topsent, 1910, 1913). Comparative material: Calycosoma validum: holotype, USNM 0 4761, U.S. F.C.S. 'Albatross', stn 2573, George's Bank, SE of Massachusetts, USA, 0 2 Sep. 1885, 40º34'18"N, 66º09'W, 3186 m, ethanol.
Description: The holotype of the new species, when inspected in June 2006 before partial dissection, was a small, intact, tubular sponge 31 mm tall and 20 mm in diameter, with a terminal osculum 9 mm in diameter, without marginalia, with wall thickness of 2 mm (Fig. 6 A). Several prostal diactins project obliquely upwards up to 9 mm from the body surface but hypodermal spicules are not raised to form a veil; groups of broken basalia project from irregular lobes of the lower body surface. The lateral surface is generally smooth to the naked eye, but, when magnified, is irregular with low conules; entrances to inhalant canals are evident through the surface lattice. The sponge is soft and pliable; color is olive brown, the same as the bottom “green-mud” substrate.
The paratype, when surveyed February – May 1996, consisted of 17 wet fragments, 0.5–3 mm in thickness, the remnants of the original six fragments reported by Topsent (1913), as probably stemming from a single large cup-shaped specimen (Fig. 6 B). Both surfaces of most fragments retain the fine spicule lattice spanning over the apertures of inhalant and exhalant canals as outlined by the choanosomal diactin bundles. Intact and broken diactins projected from one surface of most fragments, but hypodermalia were not found above the lattices of free spicules. All fragments were somewhat stiff and brittle, due to extensive but tenuous fusion of megascleres (Fig.6 D).
* no intact spicules of this type found Megascleres (dimensions given in Table 3) consist of hypodermal anchorate pentactins, hypodermal regular pentactins, pinular hexactine dermalia, pinular hexactine atrialia, large choanosomal hexactins and thick choanosomal diactins as principalia (and as lateral prostalia for the diactins), and thin choanosomal diactins. Anchorate hypodermalia (Figs. 6 C, 7A) are generally smooth with the crucially-arrayed tangential rays bent abruptly back 70–90° near their mid-points; ray tips are parabolic-rounded or bullet-shape and only the proximal ray tip is sometimes roughened near its end. Regular hypodermal pentactins (Fig. 7 B) have straight, crucially-arrayed, tangential rays, smooth except for roughening at ray ends; neither these nor the anchorate forms are erected above the lateral surfaces. Occasional hypodermalia (Fig. 7 B) are mixtures of the regular and anchorate types, with some straight rays and some shorter bent rays. Dermalia (Fig. 7 C) are almost exclusively pinular rough hexactins with the distal ray differing from the others in thickness and density and size of its proclined spines; the pinular ray is generally shorter than the tangentials but longer than the proximal ray. The pinular ray tip is cylindric with a blunt tip while the other rays are tapered and end in sharply pointed tips. Atrialia (Fig. 7 D) are rough pinular hexactins of much larger size range and slighter spination than the dermalia; in smaller forms the distal pinular ray (extending into atrial cavity) is the longest ray; in larger spicules of this type the proximal ray may be increased disproportionately and become larger than all other rays, while spination of the entire spicule is reduced or entirely lost. Large choanosomal hexactins (Fig. 7 E) with straight rays sometimes have one very short and distally heavily spined ray. Thick diactins (Fig. 7 F) serve as primary choanosomal and prostal spicules; they are slightly curved, and smooth except for fine spination just before the smooth rounded or bullet-shape spicule tips; they have no swelling at the spicule center. Occasional orthodiactins or L-form thick diactins occur. Thin choanosomal diactins (Fig. 7 G) occur in bundles; they are mostly smooth, with rounded to parabolic and occasionally inflated roughened tips and usually a slight swelling at the spicular center.
Microscleres (dimensions given in Table 3) consist of oxyhexasters, hemioxyhexasters, rare oxyhexactins, and strobiloplumicomes. Oxyhexasters and hemioxyhexasters (Figs. 6 E, 7H) are the most abundant microscleres; their short primary rays each bear 1–3 thin straight terminals; the thick primary rays are smooth while the terminal rays are covered with very fine recurved thorns detectable in LM; rare oxyhexactins of the same size occur among this spicule category (Figs. 6 F, 7I). Strobiloplumicomes (Figs. 6 G–I, 7J) are very common only in dermal and atrial surface tissues; primary rays bear a subterminal spherical inflation from which originate 3–5 whorls of sickle-shaped terminal rays of a series of different lengths, each of which is ornamented with two rows of spines on their distal concave (inner) surface; the pegs of the primary rays extending beyond the swelling are smooth and terminate in rounded tips.
Etymology: The species is named in honor of the eminent spongologist, Professor Emile Topsent, who originally described the paratype.
Remarks: Topsent (1910, 1913) was very clear in his original description of the 'Scotia' specimen, that it differed from Schulze's Calycosoma validum in several aspects, the most notable being the presence of anchorate hypodermalia (absent in C. validum) and the absence of pentactine dermalia (abundant in C. validum). He nonetheless attributed these features to malformations and individualistic variation, and assigned the Antarctic specimen to C. validum. Barthel and Tendal (1994) accepted these obvious discrepancies and rediagnosed Calycosoma and C. validum to include features of both the N Atlantic and Antarctic specimens. Tabachnick (2002b) was the first reviewer to act in moving Topsent's Antarctic specimen from Calycosoma to Lophocalyx, but suggested no species name. Menshenina et al. (2007), in their re-diagnoses of Calycosoma and Lophocalyx, noted once again the clear differences between Schulze's description of C. validum and Topsent's description of the Antarctic specimen and again stated that Topsent's specimen should be transferred to Lophocalyx pending re-analysis of the C. validum type specimen. We have here examined both Schulze's type specimen of C. validum and Topsent's original Antarctic specimen, as well as a new specimen of Lophocalyx from the Weddell Sea. We verify that the differences between C. validum and Topsent's specimen are as repeatedly noted. There are no material differences between the new ANDEEP III specimen and Topsent's original Antarctic specimen, except for megasclere fusion which is absent in the former and extensive, but tenuous, in the latter. We chose to designate the new specimen as holotype of the new species because it was complete and intact, although the smaller of the two, and designate Topsent's specimen, although the larger specimen, as paratype because it was fragmentary and severely damaged.
No single feature distinguishes the new species, L. topsenti, from the other members of the genus. Its pinular dermal hexactins separate it from the group with all or most dermalia as stauractins, L. philippinensis (Gray, 1872), L. spinosa Schulze, 1900, and L. sululanus Ijima, 1927, and from L. moscalevia Tabachnick, 1988, which has partly dermal pentactins. It differs from L. biogassi and L. oregoni, both of Menshenina et al., 2007, in having no pentactin atrialia. It differs from L. pseudovalida Menshenina et al., 2007 in the much larger size of its choanosomal hexactins, 0.26–2.84 mm versus 0.14–0.53 mm in the latter. It differs from L. atlantiensis and L. brasiliensis, both Menshenina et al., 2007, in form of its main oxyhexaster microscleres and the strongly reflected tangential rays of the anchorate hypodermalia which are only slightly or gradually recurved in those species. Finally, it clearly differs from L. profundum, described above, in having hexactine rather than diactine dermalia.
description: Published as part of Janussen, Dorte & Reiswig, Henry M., 2009, Hexactinellida (Porifera) from the ANDEEP III Expedition to the Weddell Sea, Antarctica, pp. 1-20 in Zootaxa 2136 on pages 11-15, DOI: 10.5281/zenodo.188483