Penares tylotaster Dendy, 1924

Sim-Smith, Carina & Kelly, Michelle, 2019, Review of the sponge genus Penares (Demospongiae, Tetractinellida, Astrophorina) in the New Zealand EEZ, with descriptions of new species, Zootaxa 4638 (1), pp. 1-56 : 5-8

Penares tylotaster Dendy, 1924

( Figs 1–3 ; Table 1 )

Penares tylotaster Dendy, 1924, p. 303; pl. VII, figs 16–19.

NOT Penares tylotaster, Brøndsted, 1924: 440.

NOT Penares tylotaster, Burton, 1929: 415.

NOT Penares tylotaster, Bergquist, 1961: 198.

NOT Penares tylotaster, Bergquist, 1968: 40–41.

Material examined. Type material. Holotype — NHMUK 1923.10.1.31, dry subsample from R.N.XXVII, 7 miles east of North Cape, 128 m, British Antarctica ( Terra Nova) Expedition, 1910, 16 Jul– 24 Sep 1911; NHMUK 1926.5.1.114 & NHMUK 1923.10.1.231, microscope slides from R.N.XXVII, 7 miles east of North Cape, 128 m, British Antarctica ( Terra Nova) Expedition, 1910, 16 Jul– 24 Sep 1911.

Type locality. North Cape , New Zealand .

Distribution. Only known from the type locality, North Cape, New Zealand; 128 m ( Figure 3 ).

Description. Morphology is irregularly massive, incorporating considerable calcareous debris, 75 mm wide × 40 mm thick ( Dendy 1924). Texture is firm, rigid. Surface is nodular and corrugated. A few conspicuous, semi-circular oscules, up to 3–4 mm in diameter are scattered singly over the surface of the sponge. Oscules lie flush with the surface of the sponge ( Dendy 1924). Colour in ethanol is pale yellowish grey throughout ( Dendy 1924).

Skeleton. Cortical skeleton thin (100–200 µm), poorly defined, consisting of an interwoven mesh of tangential microxeas and microrhabds that form a regular pattern around circular pores, 150 µm diameter ( Figure 1C ). Sub- dermal canals separate the cortex from the choanosome. Choanosomal skeleton has a single layer of dichotriaenes just below the cortex, cladomes uppermost ( Figure 1B ). Oxeas are more-or-less radially arranged near the surface but are confused towards the centre of the sponge ( Figure 1A ). Microxeas and tylasters are abundant and scattered throughout the choanosome, with tylasters more commonly found in the walls of the aquiferous canals.

Spicules ( Figure 2 ; Table 1 ). Megascleres —oxeas ( Figure 2A ) are small, fusiform and slightly curved; 1212 (978–1404) × 33 (22–45) µm (n = 20). Dichotriaenes ( Figure 2B & C ) are stout with a short conical rhabdome that strongly tapers to a sharp point. Rhabdome is similar in length to the width of the cladome. Occasionally, plagiotriaenes are found that are of similar size to dichotriaenes ( Figure 2D ), some of which may have the odd bifurcate clad tip ( Figure 2E ); 543 (390–637) µm long × 545 (401–652) µm wide (n = 20).

Microscleres —microxeas ( Figure 2F ) are curved or sharply angulate towards the distal ends, often centrotylote, variable in size; 198 (85–287) × 14 (8–20) µm (n = 20). Microrhabds ( Figure 2G ) are small, smooth and curved with bluntly rounded tips, most are faintly centrotylote; 55 (36–79) × 6 (4–8) µm (n = 20). Tylasters ( Figure 2H ) are very small with numerous rays that have recurved spines at the tips; 9 (7–12) µm in diameter (n = 20).

Remarks. Dendy (1924) does not specifically list microrhabds as a separate spicule type for P. tylotaster . However, from Dendy’s description of the smallest rhabds, “ Microxeas; ranging in size from about 0.034 by 0.004 mm to 0.34 by 0.017 mm. The smallest slightly curved, sausage shaped, bluntly ended, and slightly centrotylote. The largest curved, fusiform, sharply and gradually pointed at each end, ” it is apparent that he has combined both the small, bluntly rounded microrhabds and the sharply pointed microxeas in the same spicule category. While there is little size separation between the largest microrhabds and the smallest microxeas ( Table 1 ), these two spicule types can be separated by their morphology ( Figure 2F & G ).

Despite P. tylotaster being the first and only species of Penares to be formally described from New Zealand waters, we have failed to find any further specimens of this species amongst the 75 specimens examined in this study, even from collections in similar localities. Since Dendy’s (1924) publication, P. tylotaster has been recorded in the literature from the Bay of Plenty by Brøndsted (1924), from Antarctica by Burton (1929), from the Chatham Rise by Bergquist (1961), and from the Three King Islands and Hauraki Gulf by Bergquist (1968). Unfortunately, few of these specimens could be located for re-examination, but we believe that none of them are likely to be P. tylotaster based on the species descriptions by the authors and the localities they were described from. Our reasons for refuting each of the specimens as being P. tylotaster sensu stricto, is as follows:

1. Specimen from Bay of Plenty, Slipper Island, intertidal ( Brøndsted (1924) —described as possessing “ rather few dichotriaenes, the tetactines mostly being orthotriaenes … oxeas only attain a length of ca. 1000 µ and there are all intermediate stages between these and the small ones of ca. 25 µ … tylasters are here about 12–14 µ in total diameter ”. This specimen could not be located, but given the dominance of orthotrianes (not dichotriaenes as in P. tyloaster sensu stricto), the smaller size of the oxeas (cf. 1212 (978–1404) µm in P. tyloaster sensu stricto) and microrhabds (cf. 55 (36–79) µm in P. tyloaster sensu stricto), and the locality of this specimen ( P. tyloaster sensu stricto has only been recorded from Northland), we believe that it is more likely to be P. aureus sp. nov. (see Table 4). Penares aureus sp. nov. does has oxyasters instead of tylasters, but these two spicule types are often difficult to differentiate using light microscopy.

2. Specimen from Antarctica, McMurdo Sound, 252 m ( Burton 1929)—Burton provides no description or illustrations of the specimen, but simply lists the specimen, which could not be located from re-examination. Despite Burton’s application of Dendy’s (1924) species names to several Antarctic specimens, we have found very little overlap with sub-Antarctic species, and no overlap with species from northern New Zealand. Thus, the Burton species record is considered to be erroneous.

3. Specimen from Chatham Rise, Stn 6, 396 m ( Bergquist 1961)—Bergquist provides no spicule measurements, the only comments that were made were that the specimen “ concurs with the type description in all maJor respects…contains only rare dichotriaenes…contains much calcareous debris and appears to have been of a semi-encrusting habitat.” Only a slide of specimen could be located. Examination of this slide found that spicule morphology and measures did not concur with those of P. tyloaster sensu stricto, but in fact concurred with P. schulezi , which is also known to incorporate much calcareous debris (see section of P. schulezi for more details). However, Bergquist (1961) made no note of the unusual purple colouration of P. schulezi in preservation.

4. Specimen from Great Barrier Island, intertidal ( Bergquist 1968)—this specimen was found in Bergquist’s collection that is deposited in the Museum of New Zealand Te Papa Tongarewa (NMNZ PO.001397). Examination of this specimen found that it is P. aureus sp. nov.

5. Two specimens from: Hauraki Gulf (Shag Rock) 49 m; and, Three Kings Island, 54–108 m ( Bergquist 1968)—the descriptions of these two specimens differ from the type of P. tylotaster in that they all: a) have much longer microxeas (310 (210–380) µm and 340 (230–400 µm respectively, versus 198 (85–287) µm in P. tylotaster sensu stricto); b) lack microrhabds (present in P. tylotaster sensu stricto); and, c) possess both oxyasters and tylasters. Based on the species descriptions and spicule measurements we cannot attribute these two specimens to any of the species described in this paper, and thus, deem them to be unrecognisable at this stage. We could rename these two specimens, but feel that this action would be simply gratuitous as the sponges have never been collected again. Moreover, we have noted several mistakes in Bergquist’s descriptions and feel that she may have described several species under the one name (specimens vary in morphology from thinly encrusting to massive, and vary in live colour from yellowish white to grey black, a phenomenon not noted within species today). Furthermore, we are unable to re-examine and re-describe the material as the specimens could not be located—Bergquist (1961, 1968) did not assign unique specimen numbers to the specimens making it very difficult to locate the specimens. We found two other specimens registered as P. tylotaster from Bergquist’s collection deposited in the Museum of New Zealand Te Papa Tongarewa (NMNZ) that are from different locations to those above. We have examined these two NMNZ specimens and identified them as P. aureus sp. nov. (NMNZ PO.001467, see species description for P. aureus sp. nov.), and a new species of Jaspis (NMNZ PO.001391) from the Poor Knights Islands.

Unfortunately, the name P. tylotaster , promulgated incorrectly by Bergquist (1961, 1968) has been used colloquially by the New Zealand scientific community, ever since.

Figures

FIGURE 1. Penares tylotaster Dendy 1924, NHMUK 1926.5.1.114: A. Section showing the radial arrangement of megascleres near the surface and the disorganised mass of oxeas near the centre of the sponge; B. Cortical section showing the position of the dichotriaene cladomes below the cortex; C. A surface scrap preparation showing the regular pattern of microxeas surround- ing the pores.

FIGURE 2. Penares tylotaster Dendy, 1924, NHMUK 1923.10.1.31: A. Oxea; B & C. Dichotriaene; D. Plagiotriaene; E. Dichotriaene/plagiotriaene combination; F. Microxeas; G. Microrhabd; H. Tylaster.

FIGURE 3. Distribution of P. tylotaster Dendy, 1924 around New Zealand. The white outline shows New Zealand’s Exclusive Economic Zone.