Afrocucumis africana ( Semper, 1867 )

Shaikh, Iqra, Ali, Qadeer Mohammad, Thandar, Ahmed & Ahmed, Quratulan, 2023, Afrocucumis africana (Semper, 1867) (Holothuroidea: Dendrochirotida: Cladolabidae), new addition to the holothuroid fauna of Pakistan, Zootaxa 5343 (1), pp. 74-82 : 75-80

Afrocucumis africana ( Semper, 1867)

( Figures 2 & 3 )

Cucumaria africana Semper, 1867: 53 , 270, pI. 15, fig. 16; Théel, 1886: 108; Ludwig, 1887: 1236.

Pseudocucumis africana Ludwig, 1888: 815 ; Lampert, 1896: 61; Sluiter, 1901:107; Mitsukuri, 1912: 257, text-fig. 52, pI. 8, fig. 66; H.L. Clark, 1923: 417.

Phyllophorus transvectus Sluiter, 1914: 19 , fig. 7a, b.

? Orcula cucumiformis Semper, 1867: 244 , 274, pI. 40, figs. 8,9.

Cucumaria assimilis Bell, 1886: 27 ; Ludwig, 1899: 56l.

Pseudo cucumistheeli Ludwig, 1887: 1236 ,. pl. 15, figs. 12–16.

Discucumaria africana H.L. Clark, 1946: 404 .

Afrocucumis africana Deichmann, 1944: 736 ; 1948: 358; Heding and Panning, 1954: 109, text fig. 39; Clark and Rowe, 1971: 182 (dist.), text fig. 95g, pI. 30, fig. 3; Rowe and Doty, 1977: 226, fig. 2a.

Thandar, 1989: 298, text fig. 5, 9d; 2022: 69. Fig. 15; Kerr, 1994: 171; Marsh, 1994: 11; Rowe & Gates, 1995: 321; Massin,1996: 39, text fig. 27, A–E; Liao, 1997: 179, text fig. 104, a–b; Massin, 1999: 96, text fig. 79, 113c; Samyn & Vanden Berghe: 2000, 5, 18, 32; Samyn, 2003: 180, 194, text fig. 1A–C, 51A; Teo, 2010: 65, text figs. 1–4; Purwati & Wirawati, 2012: 244, fig. 10, 11 A–E; Ong, 2016: 297, text figs. 4A, 22.

? Afrocucumis stracki Massin, 1996: 40 , plate 28, figs. A–J.

Diagnosis (after Semper 1867, Thandar 2022, amended herein). A small species of Afrocucumis , reaching a length of just over 40 mm; colour in life reddish-violet, dull brown in alcohol. Tentacles in 2(?3) circles. Posterior radial processes of calcareous ring short, broken into three pieces. Ossicles in the form of thick, discoidal, lenticular plates with tiny, often occluded, holes and pyramidal knobs or low spines on surface. Sometimes with rosette-like miliary granules in body wall and/or tube feet.

Remarks. The above diagnosis is a taken from Semper (1867) and Thandar (2022) with slight amendation to include the sometimes presence of rosette-shaped granules in the body wall and/or tube feet. Both authors mention a single polian vesicle and stone canal, in contrast to Heding& Panning (1954) who state that there are numerous polian vesicles and stone canals. Whether these are intraspecific or geographic variations is unknown as the holotype came from Querimba, while Thandar’s (1990, 2022) specimens came from the east coast of southern Africa and those Heding & Panning (1954) from Bowen, Australia. Orcula cucumiformis Semper, 1867 from Zanzibar was synonymized with A. africana by Heding & Panning (1954) while Massin’s (1996) A. stracki from Ambon, Indonesia, is here also synonymized with A. africana , both with a query. In view of this and the number of synonyms this species needs to be thoroughly re-examined based on materials from different parts of the world.

Material examined. Gariyan Beach , Jiwani Makran Coast, Balochistan, Pakistan. (25º01’57’’N, 61º46’38’’E), collectors Dr. Qadeer Mohammad Ali, Iqra Shaikh and Ateeqa Baloch, 2nd December 2021, 2 specimens, intertidal zone, shallow water (cat no. MRCC-Holo 25) .

Description. Length and weight of preserved specimens 35 mm x 2 g and 40 mm x 2. 3 g. Live coloration dark purplish-black; preserved specimens turn black within 24 hrs. Body wall leathery, cylindrical, slightly rough to the touch; body tapering a little at each end. Mouth and anus terminal. Body wall thick (ca. 2.0 mm). Mouth surrounded by two circles of tentacles, an outer ring of 15 very bushy tentacles and an inner ring of 5 small tentacles. Anal teeth absent. Podia long, large, arranged in two rows along each radius.

Calcareous ring elongated; interradial plates pointed or tapering anteriorly; radial plates sub-rectangular, enlarged basally; radial processes of calcareous ring fragmented into three pieces. Single free stone canal (5 mm long); madreporite (1.3 mm), slightly wider and clearly distinguishable from stone canal ( Figure 3F ). Gonad yellowish, immature, tubules unbranched, in two tufts.

Ossicles. The large lenticular plates with pyramidal knobs/spines, described by all authors for this species, were not observed perhaps due to the juvenility of the specimens or they were affected by formaldehyde after first preservation. Such ossicles are stated to measure 246–324 µm across. However, their supposed precursors, found in our material, measured only 150–200 µm in diameter ( Figure 2A and 3C & D ) but are here suspected to develop into the characteristic large lenticular plates. Introvert ossicles ( Figure 2B and 3E ) appear as elongated straight or curved rods with 1–4 holes at each end. Tube feet deposits appear as straight or slightly curved rods (165–195 µm long) ( Figure 2F , 3C ), multilocular at their ends but with one or more lateral projections). Tentacle ossicles ( Figure 2G . 3D ), comprise straight rods, 155–285 µm long, also perforated at their extremities.

Distribution. Afrocucumis africana is among the most common dendrochiotid holothuroids in the shallow tropical-sub tropical waters of the Indo-West Pacific region but can reach a depth of 200 according to Rowe & Gates (1995). Its distribution is well documented by Clark & Rowe (1971) and Massin (1996). Rowe & Doty (1977) reported it from ( Guam, Micronesia); Rowe & Gates from various localities in Australia; Marsh & Morrison (2004) from Western Australia; Samyn et al. (2006) from East Africa; Liao (1997) from China; Massin (1999) from south-west Sulawesi, Indonesia, and Thandar (1989, 2022) from southern Africa. The synonymy given above indicates there are many other records.

Habitat. The specimens were taken from the intertidal zone, from under rock crevices but hardly attached to rocks.

Remarks. We compared our specimen with those diagnosed and illustrated by Thandar (1989, 2022), Massin (1996) and Samyn et al., (2006). Massin (1996) described the morphological features and taxonomic characters of A. africana as uniform grey-black; body wall with large (246–324 µm) lenticular, perforated plates covered with prominent pyramidal teeth. We suspect such plates are derived from small knobbed perforated plates which we illustrate in Figure 2C . According to Massin (1996) the tube feet are strengthened by straight rods perforated at their extremities (see Figure 2F ). The tentacles are provided with straight rods, 155–285 µm long, also perforated at their extremities ( Figure 2 G ). Thandar (1989) described his specimen as reddish-violet in life and dull brown in alcohol, the radial processes of the calcareous ring are broken into three segments, but one of the ventral radial plate in juvenile was fragmented transversely into two pieces, “probably an artifact or an abnormal development”. Smooth, simple, multilocular plates, common in the smaller individual (17 mm), are perhaps precursors of the large lenticular plates (144 µm -213 µm) of adults. Samyn et al. (2006) described their specimen as dark brown to nearly black, with darker podia and the typical body wall ossicles, which were large plates with diameter ranging from (100 to 290 μm) and appeared to be thick, nodular, convex, perforated, lens-like deposits; the podial deposits appear as small, multi-perforated plates and rods with terminal perforations; tentacles rods are perforated at the ends.

In our specimens the large lenticular plates with pyramidal knobs, mentioned by other workers, were not observed but the other plates are similar to those illustrated by Massin (1996) and others. The rods of the tube feet of our specimens are perforated at the ends and appear similar to those illustrated by Thandar (1989), Massin (1996) and Samyn et al. (2006). Tentacle rods are also perforated at the ends and are similar to those illustrated by Thandar (1989) and Massin (1996). The differences between our materials and that described by other workers are perhaps age-related or geographic or intraspecific variation. Interestingly Massin (1996) describes a similar species which he called Afrocucumis stracki , from Indonesia, differing from A. africana in the presence of miliary granules (which, in his illustration, appear as mulberry-like rosettes) in the tube feet; rods that are multilocular at the ends, and posterior radial processes undivided, perhaps indicating some speciation in the Indonesian region. However, on closer look we see that such granules have also been described in the tube feet of Orcula cucumiformiis by Semper himself, long regarded as a synonym of Afrocucumis africana . Whether these species are separate or not can only be determined if Semper’s A. africana from Querimba and O. cucumiformis from Australia, are re-examined. Hence, both these species are here indicated with a query (?) under the synonymy of A. africana .

Figures

FIGURE 2. Afrocucumis africana (Semper, 1867) A. preserved specimen (Cat no.MRCC-Holo 25), B. live specimen, C. developing body wall plates, D. lenticular plates, E. introvert rods, F. tube feet rods, G. tentacle rods H. calcareous ring with the posterior radial processes tucked beneath the radial plates.

FIGURE 3. Afrocucumis africana (Semper, 1867) (Cat no.MRCC-Holo 25). A. body wall plates; B. introvert; C. tube feet rods; D. tentacle rods; E. part of calcareous ring—labelled according to Ludwig’s 1888-1889 system) (IR—interradial plate, R—radial plate); F. madreporic body.