Afrocyclus bhaca, 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 : 73-75
treatment provided by
gen. et sp. nov.
Afrocyclus bhaca gen. et sp. nov.
Figs 11 View Fig E–F, 28D, 29, 32
Shell very small, depressed, discoidal; periostracum with axial costae producing spiral rows of simple hairs; operculum very fragile and duplex, exterior portion very shallowly concave, with low multispiral lamella terminating in a solid fringe, radula with two large cusps on second lateral tooth and rachidian tooth with slightly serrated upper edge.
Named for the amaBhaca people who inhabit the Mount Frere and Umzimkhulu regions, having fled from King Shaka Zulu during the wars of turmoil in the 1820s under King Madzikane.
Type material examined
SOUTH AFRICA – KwaZulu-Natal • Ngele Forest, 26 km east of Kokstad, large forest patch divided by N2 national road, Red Trail on the west side of N2 approx. 0.5 km NNW of Ngele Forest Inn hotel; 30.5331° S, 29.6827°E; 1234 m a.s.l.; 15 Apr. 2015; M. and K. Cole leg.; NMSA P1124 View Materials /T4282. ( Fig. 11 View Fig E–F) GoogleMaps
SOUTH AFRICA – KwaZulu-Natal • 1 specimen; same collection data as for holotype ELM D17891 View Materials / T177 GoogleMaps • 3 specimens; same collection data as for holotype; ELM W03855 View Materials /T178 GoogleMaps • 2 specimens; same collection data as for holotype; 3 Oct. 2018; M. Cole leg.; ELM D18357 View Materials /T194 GoogleMaps • 1 specimen; same collection data as for holotype; ELM W04055 View Materials /T193 GoogleMaps • 1 specimen (dry shell and body in ethanol); same collection data as for holotype; NHMUK 20180583 View Materials GoogleMaps • 2 specimens; Ngele Forest, Green Trail , small patch of forest approx. 0.5 km SW of hotel; 30.5406° S, 29.6802° E; 1208 m a.s.l.; 7 Apr. 2015; M. and K. Cole leg.; ELM D17900 View Materials /T179 GoogleMaps • 5 specimens; Ngele Forest, near Kokstad , mistbelt Podocarpus forest; 30.31. 5°S, 29.41. 5° E; ± 1350 m a.s.l.; 14–15 Nov. 1995; D. Herbert and L. Davis leg.; in leaf litter; NMSA V2075 /T4284 GoogleMaps • 6 specimens; same collection data as for preceding; 30.31.857° S, 29.41.076° E; 3 Mar. 1997; D. Herbert leg.; in leaf litter and under logs; NMSA V8277 View Materials /T4285 GoogleMaps • 2 specimens; same collection data as for preceding; NHMUK 20180584 View Materials GoogleMaps • 2 specimens; same collection data as for preceding; NMW.Z.2019.004.0007 GoogleMaps • 4 specimens; same collection data as for preceding; sorted from dried leaf-litter sample; NMSA V4889 View Materials /T4286 GoogleMaps • 2 specimens; same collection data as for preceding; RMNH.MOL.340759 GoogleMaps • 1 specimen; Ngele Forest, near Kokstad , mistbelt Podocarpus forest; 30.32°S, 29.38°E; 27 Mar. 1998; C. Symes leg.; in leaf litter; NMSA V6886 View Materials /T4287 GoogleMaps – Eastern Cape • 8 specimens; Mount Frere, just south of Buffalo Nek village , 10 km NW of Mount Frere; 30.8548° S, 28.8930° E; 1466 m a.s.l.; 7 Apr. 2015; M. Cole leg.; in leaf litter; ELM D17893 View Materials /T180 GoogleMaps • 3 specimens; same collection data as for preceding; ELM W03856 View Materials /T181 GoogleMaps .
Other material examined
SOUTH AFRICA – KwaZulu-Natal • 7 specimens; Ngele Forest , mist-belt Podocarpus forest; 30°32′S, 29°38′E; ± 1350 m a.s.l.; 17 Feb. 1997; D. Barraclough leg.; sorted from dried leaf-litter sample; NMSA V4867 View Materials GoogleMaps . – Eastern Cape • 2 specimens; Mount Frere, just south of Buffalo Nek village , 10 km NW of Mount Frere; 30.8548°S, 28.8930° E; 1466 m a.s.l.; 4 Oct. 2018; M. Cole leg.; in leaf litter; ELM D18356 View Materials GoogleMaps • 7 specimens; same collection data as for preceding; ELM W04054 View Materials GoogleMaps .
SHELL. Very small, very depressed, discoidal, adult diameter 2.49–3.72 mm, height 0.97–1.78 mm, diameter:height 1.83–2.58 (n = 19) ( Fig. 32 View Fig A–C). Spire almost flat, sometimes concave, usually with only the weakly mammillate protoconch projecting ( Fig. 32A View Fig ). Embryonic shell ( Fig. 28D View Fig ) just over two whorls, microscopically malleate, junction between embryonic shell and teleoconch evident with development of axial costae on teleoconch. Teleoconch comprising two whorls, very rapidly increasing, convex, suture impressed. Aperture circular, last whorl descending steeply nearing aperture, peristome simple, continuous and free. Umbilicus very wide, exposing all the whorls. Periostracum glossy and lacquer-like with well-spaced lamellate axial costae at regular intervals, the number on last whorl varying between 46 and 65 ( Table 5), which produce spiral rows of simple hairs varying from 4–15 on last whorl (4–5 and 14–15 respectively in the two populations examined) ( Fig. 32B, D View Fig ), longest at periphery and shortest around umbilicus; intervals between costae with approx. nine microscopic axial threads. Shell translucent when fresh.
OPERCULUM ( Fig. 32E View Fig ). Very fragile and duplex, outer portion consists of multispiral lamella with five whorls, height of lamellar blade very low thus operculum is very shallowly concave to almost flat, thickened horizontal ridge on lamellar blade just above disc surface; starting just after whorl 3 a long fringe of fused bristles emanates from this ridge, fused to blade and then curving outwards, leaving a furrow between fringe and vertical portion of blade, fringe of each whorl is not fused to lamella of following whorl, fringe of outer whorl extends to edge of disc; inner portion of operculum is a thin disc, without a prominent tubercle in centre.
RADULA ( Fig. 32F View Fig ). Rachidian with five cusps set a little distance below upper edge of tooth, upper edge mildly serrated, central cusp very long; first lateral tooth with four cusps and a vestigial fifth, third cusp (from centre) very long; second lateral tooth with two large cusps, second cusp (from centre) larger, a third small cusp and a vestigial fourth.
PENIS. Not examined.
Distribution and habitat
Medium altitude forests of the ‘first escarpment’ in the interior of north-eastern Eastern Cape and southern KwaZulu-Natal ( Fig. 29 View Fig ).
Eastern Mistbelt and Transkei Mistbelt Forests ( von Maltitz et al. 2003).
Afrocyclus bhaca gen. et sp. nov. differed from Afrocyclus isipingoensis gen. et comb. nov. by lacking the spiral row of extremely short hairs immediately below the suture and the protoconch was more strongly sculptured, but less so than that of A. potteri gen. et sp. nov. and A. oxygala gen. et sp. nov. The protoconch was smaller than that of A. potteri gen. et sp. nov. ( Fig. 28 View Fig C–D). The two populations examined differed in the arrangement of the spiral rows of hairs: specimens from Ngele had four–five rows concentrated around the periphery ( Fig. 32 View Fig A–B), while specimens from near Mount Frere/Buffalo Nek had 14–15 rows on the last whorl, more or less evenly distributed over the whorl ( Fig. 32D View Fig ). The latter were relatively more depressed than other populations ( Table 5). Specimens from Mount Frere are tentatively included in A. bhaca gen. et sp. nov., but may prove to be a separate species upon further study. In the molecular phylogeny they were more closely related to specimens from Ngele than to any other specimens in the Afrocyclus isipingoensis gen. et comb. nov. species complex ( Fig. 1 View Fig ), although relatively divergent compared to the genetic variation within the majority of species (see Cole et al. 2019).
Ngele and nearby forests appear to be a hot-spot of narrow range endemism in low-vagility, saproxylic invertebrates including other molluscan taxa (e.g., Gulella claustralis Connolly, 1939 ) and Onychophora ( Daniels et al. 2016). The occurrence of two distinct lineages ( A. potteri gen. et sp. nov. and A. bhaca gen. et sp. nov.) in close proximity has also been demonstrated in this region in Onychophora, which belong to ancient lineages that diverged in the Eocene or earlier ( Daniels et al. 2016). This is in contrast to findings in other molluscan taxa where populations across the region are considered to belong to the same lineage ( Herbert 2017).
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