Afrocyclus isipingoensis ( Sturany, 1898 ) 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 : 61-67

Afrocyclus isipingoensis ( Sturany, 1898) gen. et comb. nov.

Figs 27 , 28A , 29

Cyclotus isipingoensis Sturany, 1898: 161 (type loc.: Isipingo [Penther]).

Cyclophorus minimus Melvill & Ponsonby, 1898: 129 , pl. vii, fig. 9 (type loc.: Pietermaritzburg [Burnup]).

Cyclophorus (Maizania) isipingoensis – Kobelt 1902: 149 .

Chondrocyclus isipingoensis – Connolly 1939: 540 . — Herbert & Kilburn 2004: 91.

Cyclophorus minimus – Melville & Ponsonby 1899 : pl. iii, fig. 15 (operculum).

Diagnosis

Shell very small, very 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; rachidian tooth of radula with serrated upper edge, two large cusps on second lateral tooth.

Etymology

Named after the type locality, Isipingo, KwaZulu-Natal, South Africa.

Type material examined

Holotype

SOUTH AFRICA – KwaZulu-Natal • holotype of Cyclotus isipingoensis Sturany, 1898 ; in Vienna Museum, not examined; NHMW.

Syntype

SOUTH AFRICA – KwaZulu-Natal • syntype of Cyclophorus minimus Melvill & Ponsonby, 1898 ; Pietermaritzburg; Burnup leg.; NHMUK 1902.10 .1.7 .

Other material examined

SOUTH AFRICA – Limpopo • 99 specimens; Soutpansberg, Dundee Forest ; 23.017° S, 29.515°E; 24 Jul. 1999; C. Symons leg.; sorted from leaf litter; NMSA V7513 • 77 specimens; Soutpansberg, Entabeni, Goedehoop , indigenous forest; 23.0833° S, 30.1117°E; ± 950 m a.s.l.; 20 Nov. 1997; D. Herbert leg.; in leaf-litter; NMSA V5658 . – Mpumalanga • 119 specimens; Buffelskloof Nat. Res. , indigenous forest; 25.3169° S, 30.4990°E; 1300 m a.s.l.; 15 Mar. 2006; J. Horn leg.; in leaf-litter; NMSA W4486 . – KwaZulu-Natal • 28 specimens; Ngoye Forest , lower section, coastal scarp forest; 28.8330° S, 31.7170° E; ± 250 m a.s.l.; 6 Sep. 1997; D. Herbert leg.; in leaf litter; NMSA V5861 • 6 specimens; Nkandla Forest Reserve, Mdonini area , mist-belt forest; 28.7453° S, 31.1357° E; ± 1050 m a.s.l.; 21 Oct. 2003; Herbert, Bursey and Nangammbi leg.; under logs and in leaf-litter; NMSA W 1103 • 58 specimens; Vernon Crookes Nat. Res. , small patch of scarp forest; 30.2750°S, 30.5830° E; 1 Jan. 2004; D. Herbert leg.; in thin layer of leaf-litter on flat-topped boulder; NMSA W1441 • 28 specimens; Loteni, Yellow-Wood Cave area montane Podocarpus forest; 29.4150°S, 29.4800°E; 1800 m a.s.l.; in leaf-litter; 25 Oct. 1997; D. Herbert leg.; NMSA V5752 • 30 specimens; Karkloof Falls, near top of gorge, Southern Mistbelt Forest ; 29.4088° S, 30.2840°E; 22 Jan. 2010; M. Cole leg.; ELM D16902 • 3 specimens; same collection data as for preceding; ELM W03650 • 1 specimen; Karkloof Nature Reserve ; 29.3150° S, 30.2500° E; 1350 m a.s.l.; 23 Jan. 2010; M. Cole leg.; ELM D16903 • 17 specimens; Kenneth Stainbank N.R, Yellowwood Park ; 29.9122° S, 30.9390°E; 12 Jan. 2010; M. Cole and K. Cole leg.; ELM D16897 • 34 specimens; same collection data as for preceding; 12 Apr. 2011; M. Cole, R. Daniels, L. Davis and D. Herbert leg.; ELM D16898 • 1 specimen; same collection data as for preceding; ELM W03648 • 3 specimens; same collection data as for preceding; NHMUK 20120268 • 2 specimens; same collection data as for preceding; NMW.Z.2012.065.00001 • 1 specimen; Kranskop area, Ntumjambili , indigenous forest; 28.9380°S, 30.9550°E; ± 900 m a.s.l.; 9Aug. 1997; D. Herbert leg.; in leaf-litter; NMSA V5105 • 3 specimens; Kelso , dune forest behind railway station; 30.3622°S, 30.71316° E; 24 m a.s.l.; 31 Oct. 2010; M. Cole leg.; ELM D17635 . – Eastern Cape • 2 specimens; Mtentu , north bank, inlet 1.5 km upstream to first waterfall from mouth, east side of inlet; 31.2389°S, 30.0340° E; 30 m a.s.l.; 13 Jan. 2012; M. Cole leg.; ELM D17086 • 1 specimen; same collection data as for preceding; ELM W03604 • 1 specimen; Mtentu , north bank, inlet 3 km upstream of mouth, west side of inlet; 31.2295°S, 30.0182° E; 43 m a.s.l.; 12 Jan. 2012; M. Cole leg.; ELM D17006 • 1 specimen; same collection data as for preceding; ELM W03605 • 7 specimens; Mkambati Nature Reserve, between Mkambati and Strandloper Falls , forest on east bank of Mkambati River ; 31.2738° S, 30.0236°E; 15 Feb. 2011; M. Cole leg.; ELM D16913 • 5 specimens; same collection data as for preceding; ELM W03653 • 3 specimens; Mkambati, east bank Msikaba mouth; 31.3183° S, 29.9683° E; 16 Feb. 2011; M. Cole leg.; ELM D16914 • 1 specimen; Mkambati, Gwe Gwe forest, forest above Gwe Gwe cottages; 31.2904°S, 29.9897°E; 5 Mar. 2001; M. Cole leg.; ELM D17004 • 1 specimen; Mkambati Nature Reserve, Daza forest ; 31.3025° S, 29.9767°E; 16 Feb. 2011; M. Cole leg.; ELM W03688 • 2 specimens; Mbotyi, Ntsubane Forest, inland of coast, accessed along KwaNyambalala River ; 31.4615° S, 29.7129°E; 3 Mar. 2003; M. Bursey leg.; ELM D17363 • 2 specimens; Xora, Kumqolo Forest, west bank of Xora river opposite Mangrove swamp; 32.1589° S, 28.9848° E; 13 Aug. 2011; M. Cole leg.; ELM D17584 • 5 specimens; Qora, East Bank of Qora River , riverine forest; 32.4333° S, 28.6667° E; 7 Nov. 2009; M. Cole leg.; ELM D16904 • 1 specimen; same collection data as for preceding; ELM W03651 • 1 specimen; same collection data as for preceding; 9 Oct. 2011; M Cole leg.; ELM D17000 • 17 specimens; Phumalanga Farm, 7 km inland of Cintsa, riverine forest on Bulura River ; 32.8067° S, 28.0306°E; 25 Apr. 2006; Bursey, Wigley and Ndibo leg.; ELM D15030 • 12 specimens; same collection data as for preceding; 12 Dec. 2008; M. Wigley; ELM D15870 • 23 specimens; same collection data as for preceding; 16 Nov. 2009; M. Cole and M. Wigley leg.; ELM D16899 • 19 specimens; same collection data as for preceding; 1 Dec. 2009; M. Wigley; ELM D16900 • 11 specimens; same collection data as for preceding; ELM W03686 • 51 specimens; same collection data as for preceding; 31 Dec. 2010; M. Cole leg.; ELM D16901 • 9 specimens; same collection data as for preceding; ELM W03649 • 1 specimen; Umtiza Nature Reserve, Tree Dassie trail on east side of Buffalo Pass ; 33.0169° S, 27.8092°E; 21 Apr. 2006; M. Bursey leg.; ELM W03008 • 3 specimens; same collection data as for preceding; 8 Jun. 2010; M. Cole leg.; ELM D16905 • 8 specimens; same collection data as for preceding; 13 Jan. 2011; V. Ndibo, J. Glatz and R. Daniels leg.; ELM D16906 • 5 specimens; same collection data as for preceding; ELM W03652 • 5 specimens; same collection data as for preceding; 20 May 2011; M. Cole leg.; ELM D16907 • 7 specimens; same collection data as for preceding; 18 Mar. 2011; M. Cole leg.; ELM D16908 • 1 specimen; same collection data as for preceding; 1 Dec. 2011; M. Cole leg.; ELM D16909 • 1 specimen; Hogsback, downstream of Madonna and Child Waterfall ; 32.6068°S, 26.9622° E; 1060 m a.s.l.; 25 Jan. 2002; M. Bursey leg.; ELM W02835 • 1 specimen; Hogsback, Amathole Mountains, Kettlespout , forest above Hobbiton ; 32.5667° S, 26.9167° E; 31 Dec. 2008; M. Cole leg.; ELM D17007 • 10 specimens; Amathole Mountains, Stutterheim, Kologha Forest , near picnic site, Southern Mistbelt forest ; 32.5339° S, 27.4308° E; 22 Dec. 2009; M. Cole leg.; ELM D16910 • 2 specimens; Stutterheim, Kologha Forest, forest drive near Protea Hill ; 32.5339° S, 27.4308°E; 26 Jan. 2010; M. Cole leg.; ELM D16911 • 3 specimens; Stutterheim, Contour path; 32.5366°S, 27.3668°E; 16 Jan. 2015; M. Cole leg.; ELM D17873 • 2 specimens; Maden Dam, 18 km N.W. of King Williams Town ; 32.7333° S, 27.2833°E; 26 Mar. 2011; D.-J. Hodgkinson leg.; ELM D16912 • 9 specimens; Fort Fordyce , kloof with watercourse and sheer krantz; 32.6893°S, 26.5121° E; 915 m a.s.l.; 29 Dec. 2008; M. Cole leg.; ELM D16916 • 2 specimens; same collection data as for preceding; 6 Oct. 2009; M. Cole leg.; ELM D16961 .

Description

Specimens from Kenneth Stainbank Nature Reserve, Durban, approx. 9 km from the type locality Isipingo, are considered to represent the type in the following description.

SHELL ( Fig. 27 A–C). Very small, very depressed, discoidal, adult diameter 2.24–3.67 mm, height 1.09– 1.67 mm, diameter:height 1.9–2.31 (n = 16) Spire almost flat, sometimes concave, usually with only the weakly mammillate, slightly tilted protoconch projecting ( Fig. 27A ). Embryonic shell ( Fig. 28A ) approx. 2.25 whorls, microscopically malleate for approx. two whorls, axial costae begin to develop at about 2.25 whorls. Teleoconch comprising just over 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 ( Fig. 27C ). Periostracum glossy and lacquer-like with lamellate well-spaced axial costae at regular intervals, the average number on last whorl varying between 55 and 92 ( Table 5), which produce 10–12 spiral rows of simple hairs, longest at periphery (four rows) with approx. five–seven rows between periphery and umbilicus, the latter becoming progressively shorter nearer the umbilicus, and one very short row immediately below the suture; intervals between costae usually with six to nine microscopic axial threads ( Fig. 27D ). Shell translucent when fresh.

OPERCULUM ( Fig. 27 E–F). Very fragile and duplex, outer portion consists of multispiral lamella with five–six 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; long fringe of fused bristles emanates from this ridge, fused to blade and then curving outwards, leaving no furrow between fringe and vertical portion of blade, fringe of each whorl fused to lamella of following whorl, fringe of outer whorl fairly long and overlaps disc slightly; inner portion of operculum is a thin disc, in some populations side of disc facing body has a prominent tubercle or swelling in centre ( Fig. 27F ).

RADULA ( Fig. 27G ). Rachidian with five cusps, central one very long, outermost two very small to almost vestigial, cusps set a little distance below ‘top’ of tooth, top edge serrated; first lateral tooth with four cusps and a vestigial fifth, third cusp (from centre) largest; second lateral tooth with two large cusps, second cusp (from centre) largest, a third small cusp and a vestigial fourth.

PENIS ( Fig. 27H ). Shaft more or less cylindrical and laterally expanded on left side about midway down the shaft.

Distribution and habitat

This species complex is widely distributed throughout the eastern region of South Africa, from Soutpansberg mountains in Limpopo Province to the Amathole mountains in the Eastern Cape; from the coast to the Drakensberg foothills (1800 m) ( Fig. 29 ).

Indigenous forest of several classification types ( Mucina & Geldenhuys 2006): Southern and Northern Coastal Forest, Scarp Forest, Southern and Northern Mistbelt Forest, Northern Afrotemperate Forest, and Albany Thicket (Kowie Thicket) ( Hoare et al. 2006); in leaf-litter.

Remarks

Selected populations from across the range of this lineage were sampled for the molecular study and morphological examination and there is compelling evidence that A. isipingoensis gen. et comb. nov. is a species complex rather than one widespread species. Until further study is undertaken the name A. isipingoensis gen. et comb. nov. is applied to all populations with the exception of the three new species described below. Differences in the density of axial lamellae, the number and position of spiral rows of hairs, the length of the hairs, the density of microscopic axial threads between the lamellae and the strength of protoconch sculpture will need to be evaluated in conjunction with molecular evidence from more comprehensive coverage of the range of the complex.

The phylogeny inferred suggests that populations from the western end of the range (Somerset East and Bedford) belong to a distinct lineage ( A. oxygala gen. et sp. nov.). There was also a well-supported lineage in montane areas between the coast and Great Escarpment in the central Transkei ( A. potteri gen. et sp. nov.) and another lineage occurring in relatively close proximity in the north-eastern Transkei ( A. bhaca gen. et sp. nov.). The population from near the type locality had one row of extremely short hairs on lamellate costae immediately below the suture, and a gap with no hairs between this and the four rows of very long hairs near the periphery ( Fig. 27D ). Afrocyclus oxygala gen. et sp. nov. ( Fig. 30D ), A. potteri gen. et sp. nov. ( Fig. 31 D–E) and A. bhaca gen. et sp. nov. ( Fig. 32D ) lacked the extremely short row just below the suture.

The rachidian tooth of the radula is unusual in having a serrated upper edge and the cusps are set a little distance below the ‘top’of tooth. Afrocyclus isipingoensis gen. et comb. nov. ( Fig. 27G ), A. exsertus gen. et comb. nov. ( Fig. 33G ), A. potteri gen. et sp. nov. ( Fig. 31G ) and A. bhaca gen. et sp. nov. ( Fig. 32E ) showed this feature while the upper edge of the rachidian tooth of A. oxygala gen. et sp. nov. ( Fig. 30G ) was not serrated as in species of Chondrocyclus s.s.

Figures

Fig. 27. Afrocyclus isipingoensis (Sturany, 1898) gen. et comb. nov. A. Aperture view (ELM W3648). B. Dorsal view (ELM W3648). C. Ventral view (ELM W3648). D. Detail of axial lamellae of periostracum (ELM D16897). E. Portion of radula (ELM W3650). F. Penis, dorsal view, showing position behind right tentacle (ELM W3652). G. Operculum, inner portion, showing tubercle (ELM W3648). H. Operculum of specimen from near type locality (ELM W3648). I. Operculum of specimen from Mpumalanga (NMSA W4486). Scale bars: A–C = 2 mm; D, F–H = 500 µm; E = 20 µm; I = 200 µm.

Fig. 28. Protoconch detail of species of Afrocyclus gen. nov. A. Afrocyclus isipingoensis (Sturany, 1898) gen. et comb. nov. from Durban (near type locality) (ELM W3648). B. A. oxygala gen. et sp. nov. (ELM W3647). C. A. potteri gen. et sp. nov. (ELM W4052). D. A. bhaca gen. et sp. nov. (NMSA V4889). Scale bars: A–D = 200 µm.

Fig. 29. Distribution map of Afrocyclus gen. nov. T indicates type localities. Provinces and major cities are labelled.

Fig. 30. Afrocyclus oxygala gen. et sp. nov. A. Aperture view (ELM D16896). B. Dorsal view (ELM W3647). C. Ventral view (ELM W3647). D. Portion of juvenile shell, showing detail of periostracum (ELM W3647). E. Portion of radula (ELM W3646). F–G. Operculum (ELM W3647). H–I. Penis, showing position, dorsal and lateral views (ELM W3647). Scale bars: A–D, H = 1 mm; E = 20 µm; F–G = 200 µm; I = 500 µm.

Fig. 31. Afrocyclus potteri gen. et sp. nov. A. Dorsal view (ELM D14713). B. Aperture view (ELM W4052). C. Ventral view (ELM D18233). D–E. Juveniles to show variation in detail of axial lamellae of periostracum from different populations: D. Juvenile from type locality (ELM W4052). E. Juvenile from Langeni (ELM D17151). F. Operculum (ELM W4052). G. Portion of radula (ELM W3933). H. Penis, lateral view (ELM W4052). Scale bars: A, C = 1 mm; B, D–E = 500 µm; F, H = 200 µm; G = 20 µm.

Fig. 32. Afrocyclus bhaca gen. et sp. nov. A. Dorsal view (NMSA V8277). B. Aperture view (NMSA V2075). C. Ventral view (NMSA V2075). D. Juvenile to show detail of axial lamellae of periostracum (ELM D17893). E. Portion of radula (ELM W3856). F. Operculum (NMSA V2075). Scale bars: A, C = 1 mm; B, D = 500 µm; E = 20 µm; F = 200 µm.

Fig. 33. Afrocyclus exsertus (Melvill & Ponsonby, 1903) gen. et comb. nov. A. Holotype (NHMUK 1904.4.29.28). B. Aperture view (ELM D16953). C. Protoconch (ELM D16951). D. Detail of axial lamellae of periostracum (ELM D16951). E. Dorsal view (ELM D16951). F. Ventral view (ELM W3654). G. Portion of radula (ELM W3654). H. Operculum (ELM W3654). I. Penis, dorsal view (ELM W3654). J. Operculum, lateral view (ELM W3655). K. Penis, lateral view (ELM W3654). Scale bars: A = 3 mm; B, E = 1 mm; C, H–K = 500 µm; D = 200 µm; F = 2 mm; G = 50 µm.