Cladolabes kirara, Yamana & Iwaoka & Hyakutake, 2014

Yamana, Yusuke, Iwaoka, Chikako & Hyakutake, Kanako, 2014, A New Species of Cladolabes (Echinodermata: Holothuroidea: Dendrochirotida: Sclerodactylidae) from Nagasaki, Japan, with Partial Redescription of the Neotype of C. limaconotus, Species Diversity 19 (1), pp. 21-33 : 22-26

Cladolabes kirara sp. nov.

( Figs 1–7 )

Material examined. Holotype, WMNH-2013-INV-5 (anaesthetized; length 97.6 mm, width 19.4 mm). Paratypes: WMNH-2013-INV-3 (anaesthetized; length 61.2 mm, width 21.7 mm); WMNH-2013-INV-4 (anaesthetized; length 120.0 mm, width 31.3 mm); WMNH-2013-INV-6 (anaesthetized; length 66.2 mm, width 20.1 mm); WMNH- 2013-INV-7 (anaesthetized; length 86.0 mm, width 19.9 mm); WMNH-2013-INV-8 (unanaesthetized; length 43.9 mm, width 28.4 mm); WMNH-2013-INV-9 (unanaesthetized; length 34.0 mm, width 18.7 mm); WMNH- 2013-INV-10 (unanaesthetized; length 51.8 mm, width 30.1 mm); WMNH-2013-INV-11 (unanaesthetized; length 46.4 mm, width 23.7 mm); WMNH-2013-INV-12 (unanaesthetized; length 48.3 mm, width 20.8 mm).

Description. Appearance of anaesthetized specimens not drastically changed by fixation; general colour also not much affected by fixation/preservation ( Fig. 1 A–C). Tentacles and introvert dark brown. Twenty dendritic tentacles in double circle (15 + 5), including five pairs of large interradial tentacles and five single small radial tentacles in outer circle and five very small radial tentacles in inner circle ( Fig. 2 ). Body fusiform, generally variegated with blackish-grey and ochre-yellow colours; mouth anterior, anus posterior, no anal teeth; pedicels forming two longitudinal rows along each radius throughout entire body length, each row with approximately 60–130 pedicels ( Fig. 1 A–D, Table 1).

Radial elements of calcareous ring each composed of large, slender piece, constricted in middle of its anterior half, with anterior and posterior notches and with pair of long, narrow, fragile chains of small, thin, spongiform segments attached posteriorly ( Fig. 3A, B ); shorter radial elements tending to be narrower ( Table 1). Inter-radial elements of calcareous ring with no large piece, composed of single, posteriorly bifurcate chain of small, thin, spongiform segments.

Up to 20 Polian vesicles and more than 30 stone canals present, fewer in smaller specimens ( Table 1; these all entangled and difficult to count accurately); gonad tubules branched.

Only one type of ossicle found in abdominal-side interradial tentacle: finely branched rods, mean length 53–63 µ m, mean width of central stem 3.5–4.3 µ m ( Fig. 4A, B , Table 2). No large rods such as those found in some species of the dendrochirotid genus Colochirus Troschel, 1846 confirmed in any specimen.

Two types of ossicle present in introvert: 1) two-pillared tables with short spire and large disc, and 2) two-pillared tables with high spire and rudimentary disc ( Fig. 5A, B , Table 3). In three counted paratypes, former type of ossicle dominant in anterior part of introvert: mean abundance there of tables with short spires 93–100%, mean width of discs 80–91 µ m, mean number of disc holes 3.7–8.1, all depending on specimen. Latter type of ossicle abundant posteriorly in introvert: mean abundance there of tables with high spires 23–100%, mean width of discs 57–78 µ m, mean number of disc holes 0.9–2.7, depending on specimen.

Mainly two types of ossicle found in body integument: 1) two-pillared tables with rudimentary discs and distally united pillars; and 2) two-pillared tables with completely degenerated discs ( Fig. 6A, B , Table 4). Abundance of each type significantly different among three specimens observed (Χ 2 test, P <0.05), but not among six sites in the body (Χ 2 test, P>0.05). Former ossicle type dominant at all six sites: mean abundance 68–97%, depending on specimen, with row of one to five holes between two thick pillars (52–73% with two holes, depending on specimen). Height and width of those with two holes significantly different among the three specimens (Kruskal-Wallis test, P <0.05), but not among the six body sites (Kruskal-Wallis test, P>0.05): mean height 102–126 µ m, mean width 42–47 µ m, depending on specimen. Latter type of ossicle less abundant: mean abundance 3–27%, depending on specimen. Pillars of both types of ossicle frequently with small lateral perforations, and also frequently with several apical spines (cf. Fig. 5 , ip).

Mainly three types of ossicle present in pedicels: 1) endplates, 2) plates, and 3) two-pillared tables with rudimentary discs ( Fig. 7A, B , Table 5). Tables abundant, 50–64% in total in three examined paratypes; endplates and plates less common. Shape of tables variable, mostly with two holes. Endplates with approximately 276–906 holes (mean 499–827, depending on specimen); diameter 415–703 µ m (mean 567– 663 µ m, depending on specimen). Plates with 2–19 holes (mean 6.4–9.1, depending on specimen); width 101–238 µ m (mean 140–165 µ m, depending on specimen).

Distribution. So far known only from the type locality, Bojima Island, west coast of Nagasaki Prefecture, Kyushu, Japan.

Ecology. At the type locality, the new species co-occurred with the following species of sea cucumbers: Holothuria (Lessonothuria) pardalis Selenka, 1867 , Afrocucumis africana (Semper, 1867) , Stolus buccalis (Stimpson, 1855) , and Lipotrapeza sp.

Etymology. The specific name kirara , a noun in apposition from the Japanese, meaning “mica” or alluding to “the state or quality of being beautifully shiny”, was given after the name of the aquarium of the Saikai Pearl Sea Resort, which is near the sampling site.

Figures

Fig. 1. Cladolabes kirara sp. nov., lateral views, A–C, WMNH-2013-INV-5 (holotype); D, WMNH-2013-INV-10 (paratype). A, B, Living state, before (A) and after (B) anaesthetization; C, preserved state; D, preserved state, fixed without anaesthesia, tentacles and introvert entirely retracted. Abbreviations indicating sites of tissue sampling for ossicle examination: aa, anterior part of body on abdominal side; am, middle part of body on abdominal side; ap, posterior part of body on abdominal side; da, anterior part of body on dorsal side; dm, middle part of body on dorsal side; dp, posterior part of body on dorsal side; ia, anterior part of introvert; im, middle part of introvert; ip, posteror part of introvert; ped, pedicel; ten, tentacle.

Fig. 2. Cladolabes kirara sp. nov., WMNH-2013-INV-5 (holotype), showing arrangement of circumoral tentacles. Abbreviations: ir, interradial tentacle; oo, oral opening; ra, radial tentacle.

Fig. 3. Cladolabes kirara sp. nov., elements of calcareous rings, viewed from body cavity. A, Abdominal elements, WMNH- 2013-INV-3 (paratype); B, dorsal elements, WMNH-2013-INV-8 (paratype). Abbreviations: ie, inter-radial element; pp, posterior prolongation; re, radial element.

Fig. 4. Cladolabes kirara sp. nov., ossicles of inter-radial tentacle on abdominal side. A, WMNH-2013-INV-7 (paratype); B, WMNH- 2013-INV-10 (paratype).

Fig. 5. Cladolabes kirara sp. nov., ossicles of inter-radius of introvert on abdominal side. A, WMNH-2013-INV-7 (paratype); B, WMNH- 2013-INV-10 (paratype). Abbreviations: hs, two-pillared table with high spire (containing two to three cross-beams [or holes]) and a rudimentary disc; ia, ossicles in anterior part of introvert; im, ossicles in middle part of introvert; ip, ossicles in posterior part of introvert; ss, twopillared table with short spire (containing zero to one cross-beams [or holes]) and a large disc.

Fig. 6. Cladolabes kirara sp. nov., integument ossicles of inter-radius in middle part of body. A, WMNH-2013-INV-7 (paratpe); B, WMNH-2013-INV-10 (paratype). Abbreviations: am, ossicles in middle part of body on abdominal side; cdd, two-pillared table with completely degenerated disc; rd, two-pillared table with rudimentary disc; dm, ossicles in middle part of body on dorsal side; ind, table with indeterminate shape.

Fig. 7. Cladolabes kirara sp. nov., ossicles in pedicels from middle part of body on abdominal side. A, WMNH-2013-INV-7 (paratype); B, WMNH-2013-INV-10 (paratype).