Lophocalyx topsenti, Janussen, Dorte & Reiswig, Henry M., 2009

Janussen, Dorte & Reiswig, Henry M., 2009, Hexactinellida (Porifera) from the ANDEEP III Expedition to the Weddell Sea, Antarctica, Zootaxa 2136, pp. 1-20 : 11-15

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.

Figures

FIGURE 6. Lophocalyx topsenti, n. sp. A. Holotype deck photo (SMF 10606). B. Paratype, part of the fragments (RSM 1921.143.1389). C. Anchorate hypodermalia from the holotype (left) and paratype (right). D. Fusion of megascleres of the paratype. E. Oxyhexaster (SEM). F. Oxyhexactin (SEM). G. Strobiloplumicome centrum (SEM). H. Whole strobiloplumicome ensnared in oxyhexasters (SEM). I. Magnified view of terminal rays of strobiloplumicome (SEM). (All microscleres from holotype).

FIGURE 7. Spicules of Lophocalyx topsenti, n. sp. holotype (SMF 10606). A. Anchorate hypodermal pentactin in end and side views with magnified tangential ray tip. B. Regular hypodermal pentactin in end and lateral view with enlargement of tangential ray end. C. Pinular hexactine dermalium with enlargements of pinular and tangential rays. D. Pinular hexactine atrialium with enlargements of pinular, tangential and proximal ray ends. E. Large choanosomal hexactin with alternate forms of short ray. F. Thick diactin with enlargments of two ends. G. Thin choanosomal diactin with enlargements of variety of ends. H. Oxyhexaster with enlargement of a terminal ray end. I. Oxyhexactin. J. Strobiloplumicome in optical section with rays perpendicular to the page omitted, with enlargement of one primary and terminal ray.

Tables

TABLE 3. Spicule dimensions of Lophocalyx topsenti, n. sp., from the Weddell Sea, Antarctica (dimensions in µm unless otherwise noted).

	Holotype SMF 10606	Paratype RSM 1921.143.1389
parameter Anchorate hypodermalia	mean st. dev. range n	mean st. dev. range n.
tangential ray length	242 38 146–292 25	196 22 149–256 77
tangential ray width proximal ray length (mm)	21.6 5.4 12.8–32.1 25 1.62 0.59 0.86–2.47 18	27.8 3.6 16.8–33.6 30 * * * *
proximal ray width	25.0 4.8 13.9–33.9 25	28.6 4.0 16.8–37.3 56
Regular hypodermalia tangential ray length	592 33 354–1,15 25 6	636 133 457–1,534 122
tangential ray width proximal ray length (mm)	23.2 3.7 17.1–36.9 25 1.24 0.19 0.93–2.05 50	25.5 4.2 14.1–33.6 37 1.32 0.32 0.78–2.67 46
proximal ray width	24.3 3.2 18.2–34.6 25	26.3 3.9 17.9–34.2 27
Dermal pinular hexactin distal pinular ray length	107 24 71–160 25	122 25 66–185 91
ray width	9.6 1.2 6.9–11.8 25	12.3 1.8 9.9–15.8 25
tangential ray length ray width	132 17 100–162 25 7.7 1.5 5.4–11.8 25	143 1.8 99–181 131 11.9 1.9 8.2–16.3 28
proximal ray length	87 15 68–112 25	99 20 34–143 80
ray width Atrial pinular hexactin	8.0 1.3 5.9–10.9 25	11.6 1.8 8.0–16.0 25
distal pinular ray length	396 165 105–687 49	337 170 99–736 50
ray width tangential ray length	13.0 5.2 5.1–24.5 56 401 152 124–759 66	13.6 4.4 8.2–27.3 32 312 151 120–613 71
ray width	14.5 5.5 5.8–28.8 64	14.1 4.6 7.5–24.0 43
proximal ray length ray width	320 261 70–865 50 12.7 4.5 4.8–21.5 55	214 290 57–1,042 50 12.3 4.5 5.9–23.9 47
Large principal hexactin
ray length ray width	709 165 502–911 7 25.9 4.1 21.2–32.0 7	1,098 424 261–2,824 108 33.2 4.2 21.2–41.2 30
Thick diactin length (mm)	9.8 2.5 7.9–18.5 16	15.9 6.1 6.6–33.0 28
width Thin diactin length (mm)	39.5 14.1 24.8–76.4 28 3.1 1.1 1.2–5.5 27	75 33 23–140 134 4.9 2.2 1.7–9.4 30
width	12.6 3.7 6.5–20.9 25	13.8 3.8 6.7–24.0 51
Oxyhexaster diameter primary ray length	170 12 152–197 25 5.3 0.9 3.3–6.7 25	151 18 64–193 100 6.4 1.2 3.9–10.0 32
secondary ray length	80.0 5.8 70.1–94.9 25	71.5 6.7 55.0–84.6 33
Plumicome diameter primary ray length	71.6 7.6 51.3–82.7 25 13.2 1.5 10.2–15.8 25	65.3 8.5 43.2–82.8 110 14.0 1.1 11.2–18.2 101
secondary ray length	27.5 3.8 16.7–32.0 25	23.8 4.1 13.0–33.6 101