Cladiella hartogi, Benayahu & Chou, 2010

Benayahu, Y. & Chou, L. M., 2010, On Some Octocorallia (Cnidaria: Anthozoa: Alcyonacea) From Singapore, With A Description Of A New Cladiella Species, Raffles Bulletin of Zoology 58 (1), pp. 1-13 : 6-9

Cladiella hartogi , new species

( Figs. 2–5 )

Material examined. – Holotype and four microscope slides ( ZRC1999.2256 ), Terumbu Pempang Tengah, 2–4 m, coll. Y. Benayahu, 14 Jul. 1999 . Paratypes: 1 colony ( ZRC1999.1065 ), Pulau Hantu (north side of island), reef flat, coll. S. L. M. Teo & C. S. C. Lee, 30 May 1994 ; 1 colony ( ZMTAU Co 34539) [ ZRC 1999.2207 ], Pulau Hantu, 1 m, coll. Y. Benayahu, 6 Jul. 1999 ; 1 colony and 2 fragments ( ZRC 1999.2207 ), Pulau Hantu , 1 m, coll. Y. Benayahu, 6 Jul.1999 ; 1 colony ( ZMTAU Co 34540) [ ZRC 1999.2221 ], Pulau Hantu, 1–4 m, coll. Y. Benayahu, 9 Jul. 1999 ; 1 colony ( ZRC 1999.2221 ), Pulau Hantu , 1–4 m, coll. Y. Benayahu, 9 Jul. 1999 ; 1 colony ( ZMTAU Co 34537) [ ZRC 1999.2223 ], Pulau Hantu, 1–4 m, coll. Y. Benayahu, 9 Jul. 1999 ; 2 colonies ( ZRC 1999.2223 ), Pulau Hantu , 1–4 m, coll. Y. Benayahu, 9 Jul. 1999 ; 1 colony ( ZMTAU Co 34541) [ ZRC 1999.2231 ], Pulau Hantu, 1–2 m, coll. Y. Benayahu, 9 Jul. 1999 ; 2 colonies ( ZRC 1999.2231 ), Pulau Hantu , 1–2 m, coll. Y. Benayahu, 9 Jul. 1999 ; 1 colony ( ZMTAU Co 34536) [ ZRC 1999.2232 ], Terumbu Pempang Laut, (patch reef), 2–6 m, coll. Y. Benayahu, 12 Jul. 1999 ; 2 colonies ( ZRC 1999.2232 ), Terumbu Pempang Laut , (patch reef), 2–6 m, coll. Y. Benayahu, 12 Jul. 1999 ; 1 colony ( ZRC 1999.2255 ), Terumbu Pempang Tengah , 2–6 m, coll. Y. Benayahu, 14 Jul. 1999 ; 1 colony ( ZMTAU Co 34535) [ ZRC 1999.2262 ], Pulau Satumu (Raffles Lighthouse), 3–6 m, coll. Y. Benayahu, 15 Jul.1999 ; 1 colony ( ZRC 1999.2262 ), Pulau Satumu (Raffles Lighthouse), 3–6 m, coll. Y. Benayahu, 15 Jul.1999 ; 1 colony ( ZRC 1999.2266 ), Pulau Satumu (Raffles Lighthouse), 3–6 m, coll. Y. Benayahu, 15 Jul.1999 ; 1 colony ( ZMTAU Co 34538) [ ZRC 1999.2281 ], Sisters Reef, 2–3 m, coll. Y. Benayahu , 19 Jul. , 1999; 2 colonies ( ZRC 1999.2281 ), Sisters Reef, 2–3 m, coll. Y. Benayahu, 19 Jul. 1999 .

Diagnosis. – The holotype is an encrusting colony with a maximum cross-section of 120 X 80 mm and a low base of four to eight mm ( Fig. 2a, b ). The colony has elongated lobes which split at their end or sides into lobules. The lobes and lobules are mostly arranged in groups, somewhat firm, partially bent and have a tapering tip. All polyps are retracted and only occasionally indicated by the tiny pits on the surface of the lobes and lobules.

The polyp sclerites vary in size (0.020 –0.062 mm) and shape ( Fig. 3a ). The small ones are flat with irregular tubercles along their margins, while in the larger ones the tubercles are arranged at either end, separated by a bare waist and resembling dumb-bells. The lobe surface also features similar dumb-bells, 0.060 –0.095 mm long. Some possess a coarse surface and tubercles, mostly conical with blunt tips ( Fig. 3b ). Other dumb-bells have pronounced, relatively high and warty tubercles ( Fig. 3c ), similar to those revealed in the lobe interior.

The surface of the base ( Fig. 4a ) and its interior ( Fig. 4b ) contain dumb-bells 0.050 –0.090 mm long, with distinct waist and remarkably wide, tuberculate heads with high warts, up to 0.07 mm in diameter.

Colour. – The preserved colony is beige. Numerous zooxanthellae are found in the tissue.

Living features. – The expanded polyps are brown ( Fig. 5a ) and the colony surface is light gray ( Fig. 5b ). The colonies were occasionally found growing in patches.

Variation. – The 22 paratypes (see list above) differ only in size (i.e., ZRC 1999.2255 : Fig. 2c ), the smallest being with a cross-section of 20 × 25 mm and all possess the same sclerites as the holotype .

Etymology. – The species is named after the late Drs. Jacobus Cornelis (Koos) den Hartog, former curator of the Coelenterata et al., National Museum of Natural History, Leiden, Netherlands, who passed away in October 2000. Koos greatly assisted Y. Benayahu during the latter’s frequent visits to the octocoral collection in Leiden.

Remarks. – The genus Cladiella is moderately common in shallow Indo-Pacific coral reef habitats (Fabricius & Alderslade, 2001). Species of this genus have been collected in various regions, including the Red Sea (e.g., Verseveldt, 1965; Verseveldt & Benayahu, 1978; 1983); east coast Africa: Tanzania (Ofwegen & Benayahu, 1992); South Africa ( Benayahu, 1993); Mozambique (e.g., Benayahu et al., 2003); Indian Ocean: Madagascar ( Tixier-Durivault, 1966; Verseveldt, 1971); Seychelles ( Verseveldt, 1976); Laccadives (Vennam & Ofwegen, 1996); Pacific Ocean: New Caledonia ( Tixier-Durivault, 1970 a; Verseveldt, 1974); Gambier ( Verseveldt, 1977); Guam (Verseveldt, 1978; Benayahu, 1997); Ambon (Ofwegen & Vennam 1994); Bismark Sea ( Ofwegen, 1996); East China Sea: Vietnam ( Tixier-Durivault, 1970b); Ryukyu Archipelago ( Benayahu, 2002 and references therein); Taiwan ( Benayahu et al., 2004 and references therein). The only revision on octocorals of the genus Cladiella is by Tixier-Durivault (1948), who presented 44 nominal species. Since then, an additional 14 new species have been described: C. aspera Tixier-Durivault, 1970 ; C. densa Tixier-Durivault, 1970 ; C. hirsuta Tixier-Durivault, 1970 ; C. multilobata Tixier-Durivault, 1970 ; C. ramosa Tixier-Durivault, 1970 ; C. rotundata Tixier-Durivault, 1970 ; C. scabra Tixier-Durivault, 1970 ; C. subtilis Tixier- Durivault, 1970; C. humesi Verseveldt, 1974 (all from New Caledonia); C. devaneyi Verseveldt, 1977 (Rurutu Is., south of Tahiti); C. arbusculoides Verseveldt & Benayahu, 1978 (northern Red Sea); C. steineri Verseveldt, 1982 (Koh Sichang, Thailand); C. daphnae ; Ofwegen & Benyahau, 1992 ( Tanzania) and C. kashmani Benayahu & Schleyer, 1996 (Sodwana Bay, South Africa). These findings indicate the diversity of the genus Cladiella throughout the entire Indo- Pacific reef systems, bringing its total number of nominal species to 58. Undoubtedly, there is need for a thorough taxonomic revision of Cladiella species. In the absence of such a revision, the description of C. hartogi sp. nov. was facilitated by the examination of relevant type material of all species designated by Tixier-Durivault (1948, 1970 a) and in the subsequent publications ( Verseveldt, 1974, 1977, 1982; Verseveldt & Benayahu 1978; Ofwegen & Benayahu, 1992; Benayahu & Schleyer, 1996).

The elongated and divided lobes ( Figs. 2 , 5 ) of C. hartogi new species and the shape and dimensions of its warty tuberculate dumb-bells ( Figs. 3 , 4 ) are considered by us as the diagnostic features of the species. The colony shape of several Cladiella species resembles, to a certain extent C. hartogi new species, but their sclerites differ from those of the newly-described species.

The length of the dumb-bells of the following five Cladiella species falls within the size range of C. hartogi new species; however their head-diameter and tubercles differ. C. laciniosa ( Tixier-Durivault, 1944) has dumb-bells up to 0.09 mm long, with head-diameter up to 0.05 mm, and covered by simple conical tubercles. C. letourneuxi ( Tixier-Durivault, 1944) has dumb-bells up to 0.08 mm long, mostly with a narrow waist, which is often a mere line, their head-diameter up to 0.055 mm, and possessing conical tubercles. Cladiella (Tixier Durivault, 1944) has dumb-bells, up to 0.08 mm long, head-diameter up to 0.05 mm, and covered by conical or pointed tubercles. C. pulchra (Tixier Durivault, 1944) has non-retracted polyps, and thus differs from C. hartogi new species (see Fig. 2 ); its dumb-bells are up to 0.09 mm long, head-diameter up to 0.04 mm, and it possesses densely placed low-rounded tubercles. C. suezensis (Tixier Durivault, 1944) has dumb-bells up to 0.10 mm long, head-diameter up to 0.08 mm, and is mostly covered with elongate-pointed tubercles.

The colony shape of the following five Cladiella species resemble that of C. hartogi new species, but their sclerites differ. C. hirsuta Tixier-Durivault, 1970 has dumb-bells, up to 0.12 mm long, and head-diameter up to 0.08 mm. Unlike C. hartogi new species, the polyp sclerites of C. hirsuta are platelets, often with two transparent centers, pit-like, and resemble digit 8. C. ramose Tixier-Durivault, 1970 has dumb-bells up to 0.11 long, head-diameter up to 0.07 mm, and polyp sclerites with both platelets as above and rod-like ones. C. humesi ( Verseveldt, 1974) has dumb-bells, up to 0.13 mm long, with waist occasionally reduced to a mere line, head-diameter up to 0.095 mm and possessing tubercles with spiny processes. C. arbusculoides Verseveldt & Benayahu, 1978 has dumb-bells up to 0.12 mm, with hemispherical heads featuring low undulating processes.

Based on the above comparisons, it is evident that C. hartogi new species has a unique suite of characters, both in terms of colony morphology and sclerites, and that it differs from all previously described congenerics.

Figures

Fig. 2. Cladiella hartogi new species; holotype (ZRC 1999.2256): a, view of colony from above; b, side view of colony; c, paratype (ZRC 1999.2255). Scale bar 10 mm.

Fig. 3. Cladiella hartogi new species; holotype (ZRC 1999.2256): a, polyp sclerites; b, dumb-bells with course surface and tubercles from surface of lobes; c, dumb-bells with warty tubercles from surface and interior of lobes. Scale bar 0.020 mm.

Fig. 4. Cladiella hartogi new species; holotype (ZRC 1999.2256): a, dumb-bells of surface of the base; b, dumb-bells of interior of base. Scale bar 0.020 mm.

Fig. 5. Underwater photographs of colonies of Cladiella hartogi new species: a, with expanded polyps; b, with retracted polyps in their natural habitat.