Cladorhiza pentaeiros, Ekins & Erpenbeck & Hooper, 2020

Ekins, Merrick, Erpenbeck, Dirk & Hooper, John N. A., 2020, Carnivorous sponges from the Australian Bathyal and Abyssal zones collected during the RV Investigator 2017 Expedition, Zootaxa 4774 (1), pp. 1-159 : 86-88

Cladorhiza pentaeiros sp. nov.

Figure 17 , Table 5

urn:lsid:zoobank.org:act:F0591E3C-6378-4CF0-8E6D-61BF1C307F1E

Material Examined. Holotype: QM G337483 , off Bermagui , Station 44, New South Wales, Australia, 36 o 21’18”– 36 o 18’54” S, 150 o 38’38”– 150 o 39’04” E, 2821– 2687 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator IN2017_ V03 , Sample 44-115, 27/v/2017.

Etymology: penta Gr. five, eiro Gr. join in rows, string together, referring to the filaments radiating in five directions projecting from the stalk.

Distribution: This species is presently known only from type locality off Bermagui, New South Wales, Australia, at bathyal depths.

Description:

Growth form: Erect stipitate sponge showing a ‘crinorhizoid’ with robust filaments radiating upward and outward from the small conical body of lengths up to 18 mm. The stem is 59 mm long and has fine filaments radiating in five directions projecting from the cylindrical stalk ( Figure 17 A–B) and the stalk is composed of five longitudinal bundles of mycalostyles, between these five bundles arise the filaments in five parallel columns. Each filament is uniformly arranged 1 mm apart. The maximum length of the filaments are currently only 1.5 mm in length, which is probably far shorter than in life as this represents the buttressed support length only. The length of the holotype is 77 mm long and 3 mm wide.

Colour: Cream alive on deck and in ethanol.

Ectosomal skeleton: Thin and membranous with anisochelae and sigmas.

Endosomal skeleton: The endosomal skeleton of the stem consists of five longitudinal tightly packed bundles containing all three types of mycalostyles, dominated by the large mycalostyles 1 ( Figure 17 B ). Between these bundles are very thin wedges of styles, embedded in these and at right angle to the longitudinal bundles are the buttressed supports for the filaments, dominated by the middle sized mycalostyles 2 (Figiure 17 C). The capitulum filaments also consist of tightly packed longitudinal bundles of all three mycalostyles, dominated by the large mycalostyles 1 ( Figure 17 K ).

Megascleres: Large oxeote mycalostyles 1, with a wide central portion (1340-(1733)- 2310 x 22.2-(31.8)-44.2 μm, n=65) ( Figure 17 E–F), medium styles 2, often with a wide central point (552-(938)- 1420 x 9.9-(14.9)-20.0 μm, n=37) ( Figure 17 G–H), and very thin, less common sometimes sinuous styles 3 (336-(568)-896 x 3.4-(6.2)-10.7 μm, n=28) ( Figure 17 I–J).

Microscleres: The microscleres consist of very small rare anchorate ‘unguiferate’anisochelae with three large alae and three smaller alae on each end (16.3-(22.0)-25.3 x 1.6-(2.0)-2.3 μm, n=13) ( Figure 17 D ) and rare thin sigmas (26.6-(34.3)-42.8 x 1.2-(1.6-)2.0 μm, n=6), although it is possible these are non-native ( Figure 17 L ).

Molecular data: It was not possible to get unambiguous molecular data from the type material.

Remarks: This new species bears some resemblance to the Atlantic species Cladorhiza inversa Ridley & Dendy, 1886 , but it differs mainly by the presence of the lateral filaments in the stem. It also differs by the medium sized styles, and the thinner styles instead of the tylostyles in C. inversa and the slightly smaller anisochelae. This species also resembles C. linearis Ridley & Dendy, 1887 and the sample from Lévi, (1964). However, as well as the inclusion of the capitulum filaments, this species differs by the smaller sizes of mycalostyles, the smaller isochelae, and the presence of the very thin styles. Cladorhiza iniquidentata Lundbeck, 1905 , redescribed beautifully by Hestetun et al. (2017b) has chelae with seven upper teeth and five lower teeth. Cladorhiza segonzaci Vacelet, 2006 , also has a similar closely packed filament structure, but is easily distinguished by the five alae on the anisochelae, the presence of sigmas and sigmancistras. Cladorhiza thomsoni Topsent, 1909 , also well re-described by Hestetun et al. 2015 also has the close set filaments, but this is differentiated by the larger anisochelae with five teeth at each end of the anisochelae and the smaller mycalostyles.

Figures

FIGURE 17. Cladorhiza pentaeiros sp. nov. A. Holotype QM G337483. B. Base of the stem showing the filaments emerging from between the longitudinal columns of mycalostyles. C. SEM of the base of the stem, the arrows are pointing to the filament bases. D. Small tridentate ‘unguiferate’ anisochelae. E. Large mycalostyle 1. F. Magnified ends of the mycalostyle illustrated in E. G. Medium-sized mycalostyle 2. H. Magnified ends of the mycalostyle illustrated in G. I. Thin mycalostyle 3. J. Magnified ends of the thin mycalostyle illustrated in I. K. roots showing longitudinal mycalostyles. L. Sigma.