A new species of phyllophorid dendrochirotid, collected from subtidal waters off the east coast of South Africa, is described as Stolus kilberti sp. nov. in the subfamily Thyoninae. It is distinctive in the form of its calcareous ring and body wall plates in combination, and appears to be closely related to S. rapax (Koehler &amp; Vaney, 1908) from the Bay of Bengal, differing from it in having elongated, rather than spherical multi-layered plates If the calcareous ring were not fragmented the species could well be referred to the genus Pseudothyone Panning, 1949 of the subfamily Sclerodactylinae, closely allied to P. mosaics (Koehler &amp; Vaney, 1910) from the Persian Gulf. The remarkable similarity in the body wall deposits of genera currently classified in two separate subfamilies challenges the use of the calcareous ring to separate subfamilies, since it demands a degree of evolutionary convergence which hardly seems probable. Of the eleven nominal species of Stolus, eight are keyed and a table provided to compare the three similar species - S. kilberti, S. rapax and P. mosaica

Rajpal, V

Thandar, A.S.

English

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130 S. Afr. J. 7001. 1999, 34(3) Stolus kilherti, a new species from the east coast of South Africa (Echinodermata: Holothuroidea: Dendrochirotida) with a key to the genus Stolus Selenka V. Rajpal and A.S. Thandar Zoology Department, University of Durban-Westville, Private Bag X54001. Durban. 4000 South Africa thandar@pixie.udw.ac.za Received 13 Novemher 1998; accepted after revision I A1arch J 999 A new species of phyllophorid dendrochirotid. collected from subtidal waters off the east coast of South Africa. is described as Sto/us kilberti sp. nov. in the sUbfamily Thyoninae. It is distinctive in the form of its calcareous ring and body wall plates in combination, and appears to be closely related to S. rapax (Koehler & Vaney, 1908) from the Bay of Bengal, differing from it in having elongated. rather than spherical multi-layered plates. If the calcare-ous ring were not fragmented the species could well be referred to the genus Pseudothyone Panning, 1949 of the subfamily Sclerodactylinae. closely allied to P. mosaica (Koehler & Vaney, 1910) from the Persian Gulf. The remarkable similarity in the body wall deposits of genera currently classified in two separate subfamilies chal-lenges the use of the calcareous ring to separate subfamilies, since it demands a degree of evolutionary conver-gence which hardly seems probable. Of the eleven nominal species of Sto/us, eight are keyed and a table provided to compare the three similar species - S. ki/berti, S. rapax and P. mosaica. Introduction A single complete specimen of a dendrochirotid holothuroid dredged at 40 m off Liefeldfs Rock, northern Kwa-Zulu-NataL South Africa, is here described as Stolus kilherti sp. nov. The genus Stolu,\' was hitherto represented in south-ern Africa by only its type species, Stolus huccalis (Stimpson, 1856). The new species appears to be unique in the form of its calcareous ring and spicules in combination and is referred to Stolus on the basis of the diagnosis provided by Panning (1949: 462). Thandar (1990), in his revision of the southern African phyl-lophorid holothuroids, recorded nine species in the subfamily Thyoninae - seven in the genus Thyone, one in Thyonina and one in Stolus. Since then one more Thyone species has been described (Thandar & Rajpal in press). The description here of Slolus kilberti increases to 1 I the number of Thyoninae and to 13 the number of Phyllophorids (sensu Pawson & Fell 1965), currently known from southern Africa. In his revision of the family Cucumariidae, Panning (1949) separated the subfamily Thyoninae from the Sclerodactylinae on the basis of the presence of a completely fragmented mosaic-like calcareous ring in the former. In the latter sub-family only the posterior processes of the ring are stated to be subdivided and not the plates themselves. He included nine genera in the Thyoninae with the genus Sfolus as the only one characterised exclusively by either smooth or knobbed plates in the body wall. Of the nine species included in the genus Stolus by Panning (1949) only the following seven remain: - co;:nalus (Lampert, 1885) - punctatus (Ohshima, 1915) - molpadioides (Semper, 1868) - buccalis (Stimpson, 1856) - canescens (Semper, 1868) - rapax (Koehler & Vaney, 1908) - minutus (H.t. Clark, 1938) Stolus hUftoni (Dendy, 1896) has long been referred to their genus Placothuria by Pawson & Fell (1965) and S. microp-unctalus (Sluiter. 1910) has been referred to the synonymy of Thyone helli Ludwig, 1887 (= Pseudothyone helli) by Deich-mann (1954) and confirmed by Pawson & Miller (1981), Two more species have recently been referred to this genus, namely S conjzmgens (Semper, 1868) by Clark & Rowe, 1971 and S. papilla/us (Sluiter. 1887) by Massin, 1987. How-ever, S. minu/us (Clark, 1938) probably based on ajuvenile, is suspected by Rowe & Gates (1995) to be synonymous with S. conjungens, whereas S. papillatus appears to be referrable to the genus Pseudofhyone in the subfamily Sclerodactylinae (sensu Panning 1949 and Thandar I 989b) or, according to Massin (pers. com.) perhaps to the subfamily Sclerothyoni-nae. Hence the genus is here considered to be comprised of only seven valid species. To this is now added S. kilherti sp. nov. from South Africa which appears to be quite close to S. rap ax (Koehler & Vaney, 1908) as well as to Pseudothyone mosaica (Koehler & Vaney, 1910). All eight species are here keyed. Material and methods The single specimen was dredged by collectors from the Natal Museum on board the R.V. Meiring Naude, off the KwaZulu-Natal north coast on 9 June 1988. The specimen is deposited in South African Museum, Cape Town. with SAM-A catalogue number. The preparation of spicules for light and scanning electron microscopy is described else-where (Thandar 1989a). Key to the species of Sto/us 1. Body wall deposits single-layered plates ............ 2 body wall deposits multi-layered plates ............. 7 2. body wall plates somewhat smooth ................ 3 body wall plates distinctly nodu lar ................. 4 introvert with irregular rosettes , .... , ............. . .... , . . . .. . ............ c()gnatus (Lampert. 1885) introvert with multilocular plates ............. , .... . . .. . ......... ". . ..... punc/a/us (Ohshima. 1915) Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).S. Afr. J. Zool. 1999, 34(3) 4. body wall plates (buttons) oval, predominantly quadri-locular ....................................... 5 body wall plates rhomboidal, multilocular ........... . · , ... , , , . , ........... . molpadioides (Semper, 1868) 5. knobs of plates large, central ones forming handles on both sides; multilocular plates absent from body wall ... · .. , .................... huccalis (Stimpson, 1856) knobs of plates small or large, central ones not united by a handle but may form a short one or two-pillared spire on one side only ................................. 6 6. knobs of plates large, central ones from plates of only the superficial layer of skin forming a pointed spire; other plates not spired · ....................... canescens (Semper, 1868) knobs relatively minute; central knobs often forming a short two-pillared spire on one side ................ . conjungens (Semper, 1868) body wall plates rounded, compact, about I mm in diame-ter ................. rapax (Koehler & Vaney, 1908) body wall plates rectangular to triangular to irregular, never rounded, up to 0.50 mm in diameter .......... . · ........................ , , ...... kilberli sp. nov. Family Phyllophoridae Oestergren, 1907 Subfamily Thyoninae Panning, 1949 Genus Stu/us Selenka, 1867 Diagnosis (modified from Panning 1949: 462): Tentacles 10, ventral two much reduced. Calcareous ring conspicuously tubular with the radials carrying long paired prolongations, both ring and prolongations finely broken into a mosaic of numerous pieces. Spicules of body wall only in the form of smooth or knobbed plates (,buttons'), the latter often quite regular with 10-12 marginal knobs and four holes, whereas the former sometimes complex, multi-layered. Stolus kilberti sp. nov. (Figures 1 & 2) Diagnosis Body cylindrical, lJ-shaped, colour in alcohol, uniformly white. Tentacles 10 (ventral two reduced). Podia dense, uni-formlv scattered. Plates and processes 'of calcareous ring frag-ment~d. Anterior projections of both radial and interradial plates bifid. Deposits of body wall mostly complex. multi-layered, smooth plates; a few simple smooth plates also found. Podia with reduced end plates, two-pillared tables and other simple to complex plates, similar to those of body wall but much smaller. Tentacles with rods and rosettes. Introvert with tables and rosettes. Type South African Museum, Cape Town, SAM-A27727. Type locality North East of Liefeldt's Rock, Zululand, South Africa (27°42.9' S. 32°39.1' E), 40 m. Etymology The new species is named after its collectors, Drs Richard Kilburn and Dai Herbert, malacologists from the Natal Museum. Pietermaritzburg. 131 Description Form cylindrical, U-shaped (Figure 2C): dorsal and ventral surfaces not clearly distinguishable. Length along ventral sur-face 37 mm, along dorsal surface 24 mm, width in mid-body 4 mm, tapering to 2 mm and 1.5 mm at anterior and posterior ends respectively. Colour, in alcohol. uniformly white. Body wall creased and villose. Podia, small, dense, non-retractile, uniformly scattered throughout the body, of same colouration as body wall. Tentacles 10, ventral two reduced. Anus flanked by 10 distinct papi Ilae and five calcareous teeth. Calcareous ring complex, tubular. elongate (Figure ID). Radial and interradial plates fused for most of their length and subdivided into a few large pieces; radial plates anteriorly bifid each with a deep depression at anterior end for insertion of retractor muscle. Anterior projections of interradial plates also bifid but less pronounced, triangular, almost same length as those of radial plates. Total height of ring about 5 mm, including posterior processes, the latter, made up of 8-11 pieces of calcite, about 1.5 x height of ring. Pol ian vesicle single, sac-like. Stone canal short, white, straight; madreporite (Figure I C) well formed, both lodged in dorsal mesentery. Respiratory trees well-branched, right slightly longer than left both unite before opening into cloaca. Gonadal tubules not observed. specimen probably immature. Longitudinal muscles thin. unpaired. Retractors arise from extreme anterior end of longitudinal muscles as single strands, all more or less at same level. Spicules of body wall predominantly in the form of large. smooth, complex, somewhat imbricating, multi-layered elon-gate, sometimes triangular plates. 260-470 J.1m in length (mean 370 ~lm) (Figures I A&B and 2A). Pedicel deposits in the form of tables and plates. Table discs (Figures IF & 2D) curved, multilocular, elongate to somewhat circular or irregu-lar in shape, 90-140 ~Im in length (mean /16 J.1m); spire two-pillared. 70-11 0 ~Lm high (mean 87 ~lIn), tapering to a smooth spine; a few tables with reduced spires also found. Pedicel plates (Figures IE & 28) simple, one-layered to complex, multi-layered. 75-150 ~Lln (mean 1 07 ~lm). End plates reduced, rounded. Introvert deposits tables and rosettes (Fig-ures IH & 2E), the former, either with smooth, ilTegular, mul-tilocular discs and 2-pillared spires terminating in 1-6 large teeth, or with nodular rosette-like discs and a low 2-pillared spire often reduced to paired knobs on disc. Rosettes of intro-vert as minute, branched rods. Tentacles with perforated rods and minute branched rosettes of the same form as those of the introvert (Figures IG & 2F). Distribution Known only from type locality. Remarks This species is strongly characterized by the almost exclusive presence of multilayered, complex, smooth plates in the body wall and a mosaic-like calcareous ring with fairly long, paired posterior processes. Plates of the type found in the body wall of this species are variable in shape and never occur as rounded formations. They are, in addition. always smooth and never knobbed. Such plates in combination with a complex calcareous ring have only been reported in the genera Slolus and Pseudothyone, which fall respectively in two separate Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).132 s. Afr. 1. Zool. 1999, 34(3) I 0.1 mm I 1 mm I 1 RIm IO.05mm l Figure I SloJus kilberti sp. nov. (A) complex, multi-layered plates from body wall; (B) fev. simple plates from body walJ; (C) madreporic body; (D) part of calcareous ring; (E) pedicel plates; (F) pedicel tables; (G) tentacle deposits; (H) introvert deposits Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).s. Afr. J. Zool. 1999,34(3) 133 Figure 2 Si~/US kilberii sp. nov. (A,B,D-F) SEM micrographs; (A) plates from the body wall : (8) pedIcel pl<ltes: (C) entire. (D) pedicel tables. (E) inlrovert deposits; (F) tentacle deposits Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).134 subfamilies: the Thyoninae in the family Phyllophoridae (sensu Pawson & Fell 1965) and the Sclerodactylinae in the family Sclerodactylidae (sensu Pawson & Fell 1965). Only S. rapax (Koehler & Yaney, 1908) and P. mosaica (Koehler & Yaney, 1910) have multi-layered rounded plates. It appears that both S. rapax and P. mo.wica are similar except for the undivided nature of the calcareous ring and the absence of body wall tubercles in the latter. Since Koehler and Yaney are authorities to both these species, it is best to let them stand until a direct comparison based on type material is under-taken, Whether we are justified in retaining two very similar species in different families and/or subfamilies is questiona-ble without having to invoke parallel evolution and conver-gence. An examination of the calcareous ring of P. rnosaica may indicate subdivided plates, or that of S. rapax may show that the plates are undivided. However, the similarity of the calcareous ring, body wall plates and pedicel spicules of these two species are so remarkable that one is inclined to consider them as being at least congeneric if not conspecific. In fact Koehler and Yaney (1910), in their comparison of mosaica and rapax, distinguished them only by the presence of tuber-cles on the body wall of the latter species. From the length and the degree of fragmentation 0 f the posterior processes, it appears that both these species belong in the subfamily Thy-oninae. The new species is distinct from both P. mOSalca and S. rapax in several features, especially the arrangement of podia, bifid anterior tip of the interradial plates and the fonn of the pedicel and body wall deposits. These and other differ-ences are summarized in Table 1. Acknowl edgem e nts We thank Drs R. Kilburn and D. Herbert for entrusting this unique specimen to us. Financial assistance from the Founda-tion for Research Development and the University of Dur-ban-Westville is gratefully acknowledged. References CLARK, IlL 1938. Echinoderms from Australia.lt;fem. iv/us. compo S. Afr. J. Zool. 1999\ 34(3) /.001. Harv. 55; 1-596. CLARK, ILL & ROWI~.I-'.W.E. 1971. Monograph ol'shallow-water Indo-west Pacific Echinoderms. London: Trustees of the British Museum (Natural lIistory). 23Rpp. I 00 fig~. 31 pis. DElCIIMANN, E. 1930. The holothurians of the westcrn part oJ'the Atlantic Ocean. Bull. Mus (Oml) Zool. Ilarv. 71(3): 41-226. DEICHMANN.E 1954. The bolothumll1s of the Gulf of MexicCl. Fishery Bull. Fish ft't1dl. S·erv. (j.s. 55: 3~ 1-4! O. KOEHLER, R & YANEY. C. I ()OR Littoral r lolothuroidea. Echino-derma ofthc Indian Museum. Calcutta: I 54. KOEIILER, R. & V ANEY, C. 1910. Description d'Holothuries nour-velles appartenant au Muscc [nelien. Rec. indian Mus. 5: 89-103. MASSIN, C. 1987. lIolothuries nouvelles et pen connues recoltees en Indonesie au cours de la Snellius - [I E\.pedition. Bull. insl Roy .\'ci. Na Bell Bio!ogie 57: 97-121. OHSHIMA, II. 1915. Report 011 the hoJotblirians collected by the United States Fisheries Steamer Albatross in the north western Pa-Cific during the summer of 11)06. Pro( (/ ,"'. iVO! .Hus. 48: 2 I 3-291. PANNING, A. 1949. Ycsllch einer NeLlorelnung der Familic Cllcumar-iidae (Holothurioidca. Dcndrochirota). Zool . .Ih. 78: 404-470. PAWSON, DL & FELL, I-LB. 1965. A revised classification of the dendrochirDte holothurians. Breviora 214: 1-7. PAWSON, D.L & MILLER. lE. 1981. Western Atlantic sca cucum-bers of the genus Thyone. with descriptions of two new spccies (Echinodermata: Holothuroidea). Proc. Bioi. 5·;oc. Wash 94(2); 391-403. ROWE, F.W.E. & GATES. J. 1995. Echinodermata. Wells. A. (eel.) Zoological Cataloguc of Australia. Yol. 33. Melhourne: CSIRO Australia xiii 510pp. SEMPER, C. 1868. Holothurien. RClscn 1m Archipel der Philipplnen. 2. Wisscnschaltliche Resultatc. Weisbaden: 1-288. THANDAR, AS. I 989a. A new species or a phyllophorid holothurian from southern Africa. J Zoo/. Lond 219; 637-644. THANDAR, A. S. 198911. The sclcrodactylid holothurians ofsollthern Africa, with the eredion of one new subfamily and two new genera (Echinodermata: Holothuwidea). SAIl' J Zoo!. 24(4): 290-304. THANDAR, A.S. 1990. The phyllophorid holothurians of southern Africa with the erection of a new genus. S. Afr . .J. Zoo/. 25' 207-233. THANDAR. A.S & RAJPAL. Y. In press. A new dendrochirotid spe-cies from the ca')t COC;l.-;t of South AtI·j(;1.l (Echinodcrmata: Hol-othuroidca). J. 7.001 I,ond. Table 1 Comparison of principal characters of Stolus rap ax, S. ki/berli and Pseudothyone mosaica Length Colour Tubercles Tubefeet distribution Calcareous ring Body wall deposits Pedicel deposits Sta/us rapax (Koehler & Vaney, 1908) 10-25 mm Whitish Present Arranged in double rows along the radii, diminishing to single rows towards the anterior and posterior ends, also found scattered along interambulacra, becoming denser ventrally Radial plates subdivided. interracial plates compact. non-bitld anteriorly Rounded, compact, multi-layered plates, I mm ih diameter 1 abies with regular, curved, elongate discs and 2-pillared spires tenninating in a blunt tip Pseutiofhyane mosaica (Koehler & Vaney. 1910) 12mm ? Absent Restricted to ambulacra. those ofventraJ surface somewhat large Radial and interradial plates compact. the latter not bifid anteriorly Imbricating, curved plates of variable size, superimposed in 2 to .1 layers, thus forming complicated anasto-mosing trabeculae Tables with curved, elongate discs and 2-pillared spires, terminating in a blunt tip SIOIIIS kllnerll sp. nov. 37mITI Whitish Absent Scattered uniformly throughout body 'Wall. rather villose Radilll and interracial plates subdivided. interradial plates bifid anteriorly ElongL1te to trinngul aT. m LIlli-layered plates. 0.26-047 mill in length. never rounded. smaller. smooth. simple plates <llso found 1 "ble" with curved. elongate or suh-circular to irregular discs ,lIld 2-pilJared spires terlllillating in a poi Ilt~d tip Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).

Stolus kilberti, a new species from the east coast of South Africa (Echinodermata: Holothuroidea: Dendrochirotida) with a key to the genus Stolus Selenka

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Stolus kilberti, a new species from the east coast of South Africa (Echinodermata: Holothuroidea: Dendrochirotida) with a key to the genus Stolus Selenka

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