Chondrocyclus devilliersi, Cole, 2019

Cole, Mary L., 2019, Revision of Chondrocyclus s. l. (Mollusca: Cyclophoridae), with description of a new genus and twelve new species, European Journal of Taxonomy 569, pp. 1-92 : 37-39

Chondrocyclus devilliersi sp. nov.

urn:lsid:zoobank.org:act:3F362337-8D53-4763-A67D-9852125813E1

Figs 10I, L , 16A , 18

Chondrocyclus putealis – Herbert & Kilburn 2004: 91 .

Diagnosis

Shell small, depressed, lenticular; protoconch not mammillate; periostracum with widely spaced axial costae developing at the periphery broad rounded flanges, semi-circular in shape; operculum duplex, exterior portion very shallowly concave to almost flat, with step-shaped multispiral lamella terminating in a short fringe of fused bristles.

Etymology

Named for Div DeVilliers whose unwaivering dedication to nature conservation in the Eastern Cape province, and the Transkei in particular, has helped preserve the remaining forests and their biota.

Type material examined

Holotype

SOUTH AFRICA – Eastern Cape • Nqadu Forest, 19 km north of Mthatha, Transkei Mistbelt Forest ; 31.4173° S, 28.7320° E; 17 Jan. 2017, M. Cole and R. Cawood leg.; in leaf litter; NMSA P 1141 / T 4312. ( Fig. 10 I–L)

Paratypes

SOUTH AFRICA – Eastern Cape • 44 specimens; same collection data as for holotype; ELM D18243/ T 173 • 33 specimens; same collection data as for preceding; ELM W 3962 / T 174 • 4 specimens; same collection data as for preceding; NMSA P 0641 / T 4158 • 1 dry specimen; same collection data as for preceding; NHMUK 20180581 • 3 specimens in ethanol; same collection data as for preceding; NHMUK 20180582 • 1 specimen; same collection data as for preceding; NMW. Z.2019.004.00001 • 2 specimens in ethanol; same collection data as for preceding; NMW. Z.2019.004.00002 • 1 specimen; same collection data as for preceding; NMW. Z.2019.004.00003 • 3 specimens in ethanol; same collection data as for preceding; RMNH.MOL.340754 • 1 specimen; same collection data as for preceding; RMNH.MOL.340755 • 11 specimens; Nqadu Forest, 19 km north of Mthatha, Transkei Mistbelt Forest ; 31.4241° S, 28.7547° E; 16 Apr. 2015; M. and K. Cole leg.; in leaf litter; ELM D17922/ T 116 • 4 specimens; same collection data as for preceding; ELM W 3861 / T 117 • 2 specimens; same collection data as for preceding; 26 Jan. 2013; M. Cole, V. Ndibo and T. Morgenthal leg.; ELM D17147/ T 115 • 1 specimen; same collection data as for preceding; ELM W 3716 / T 167 • 1 specimen; Nqadu Forest, north of Mthatha, Southern Mistbelt Podocarpus forest; 31.4278° S, 28.7520° E; 12 May 2001; D. Herbert leg.; in leaf litter; NMSA V 9111 / T 4110 • 4 specimens; Bele Forest, 32 km NNW of Mthatha, northern end of Langeni escarpment, Transkei Mistbelt Forest ; 31.3279° S, 28.6790° E; 18 Jan. 2017; M. Cole and R. Cawood leg.; in leaf litter; ELM D18238/ T 175 • 12 specimens; same collection data as for preceding; ELM W 3949 / T 176 • 2 specimens; same collection data as for preceding; NMSA P 1126 / T 4295 .

Description

SHELL ( Fig. 18 A–C). Small, depressed, lenticular, adult diameter 5.01–6.01 mm, height 2.59–3.17 mm, diameter:height 1.70–2.16 (n = 16). Spire not much raised, apex almost flat. Embryonic shell ( Fig. 18 D– E) nearly 2.25 whorls, microscopically malleate, junction between embryonic shell and teleoconch evident with development of costae on teleoconch. Teleoconch comprising 2.75 whorls, convex, rapidly increasing, suture deeply impressed. Aperture circular, last whorl descending near aperture, peristome simple, continuous and free. Umbilicus wide and deep, exposing all the whorls. Periostracum glossy, honey-brown and lacquer-like with widely spaced lamellate axial costae at regular intervals, 65–77 (n = 4) on last whorl, expanded into a single row of semi-circular flanges at periphery ( Fig. 18D ). Shell translucent, glossy, corneous yellow-brown when fresh.

OPERCULUM ( Fig. 18 F–G). Duplex, outer portion slightly concave; lamella of outer multispiral portion with 4.5 whorls, step-shaped; upper edge of lamella thin and projects slightly above fringe. Radula ( Fig. 18H ). Rachidian with five cusps, central cusp approx. twice length of outer two on each side; first and second lateral teeth similar but second is slightly larger, each with four cusps and a vestigial fifth; first three cusps gradually increasing in size from centre outwards and fourth very small.

PENIS ( Fig. 18 I–J). Shaft dorsoventrally flattened, with lateral expansions of shaft on both sides towards distal end but more prominent on left, with numerous annular rugae, smooth distal end narrower, intromittent organ relatively long.

Distribution and habitat

Known only from two forests, Nqadu approx. 20 km north of Mthatha and Bele to the north-west. Transkei Mistbelt Forest ( von Maltitz et al. 2003), in leaf litter ( Fig. 16A ).

Remarks

Chondrocyclus devilliersi sp. nov. has several unique morphological features and in the molecular analyses it was not closely related to other species of Chondrocyclus in the Eastern Clade. Although the majority of adult specimens are worn even when collected alive and display few features of the periostracum, the fresh juveniles reveal that there is only one row of expanded flanges around the periphery of the shell ( Fig. 18D ) and not multiple spiral rows on the body whorl as in other members of the Eastern clade. This resembles the pattern in C. convexiusculus and species in the Southern-Eastern Cape clade.

The radula resembles that of the coastal taxa C. bathrolophodes , C. putealis and C. cooperae sp. nov. with varying sizes of cusps, while the flat operculum is quite unlike the deeply concave operculum of these species.

Figures

Fig. 10. Holotypes of species of Chondrocyclus Ancey, 1898. A–B. C. herberti sp. nov., diameter 3.70 mm (NMSA P1043/T4277). C, F. C. silvicolus sp. nov., diameter 5.82 mm (NMSA P0639/T4156). D–E. C. amathole sp. nov., diameter 6.01 mm (NMSA P0640/T4157). G–H. C. pondoensis sp. nov., diameter 5.92 mm (NMSA P0643/T4160). I, L. C. devilliersi sp. nov., diameter 5.23 mm (NMSA P1141/ T4312). J–K. C. pulcherrimus sp. nov., diameter 4.34 mm (NMSA W9272/T3075). M–N. C. cooperae sp. nov., diameter 4.93 mm (NMSA W9271/T3074). O, R. C. langebergensis sp. nov., diameter 5.13 mm (NMSA P0642/T4159). P–Q. C. kevincolei sp. nov., diameter 4.24 mm (NMSA P9270/T3073).

Fig. 16. Distribution map of Chondrocyclus species in the Eastern clade. A. Species in KwaZulu-Natal and the eastern half of the Eastern Cape, on the coast and extending inland. B. Species on the Eastern Cape coast. Note that the range of C. pondoensis sp. nov. overlaps with that of C. putealis Connolly, 1939 and C. cooperae sp. nov. T indicates type localities. Major cities and rivers are labelled.

Fig. 18. Chondrocyclus devilliersi sp. nov. A. Aperture view (ELM W3962/T174). B. Dorsal view (ELM W3962/T174). C. Ventral view (ELM W3962/T174). D. Dorsal view of juvenile shell (NMSA V9111/ T4110). E. Protoconch (NMSA V9111/T4110). F–G. Operculum (ELM W3962/T174). H. Portion of radula (ELM W3962/T174). I. Penis, lateral view (ELM W3962/T174). J. Penis, dorsal view ((ELM W3962/T174). Scale bars: A–C = 2 mm; D, I–J = 1 mm; E = 200 µm; F–G = 500 µm; H = 50 µm.