Cyclostoma (Cyclophorus) convexiusculum Pfeiffer, 1855: 104
Cyclophorus convexiusculus var. minor Benson, 1856: 438
Chondrocyclus convexiusculus – Kobelt 1902: 230
Connolly 1939: 536
Herbert & Kilburn 2004: 92
Revision of Chondrocyclus s. l. (Mollusca: Cyclophoridae), with description of a new genus and twelve new species
Cole, Mary L.
European Journal of Taxonomy
2019
2019-10-22
569
1
92
5XZH9
(Pfeiffer, 1855)
Pfeiffer
1855
[512,1075,267,294]
Gastropoda
Cyclophoridae
Chondrocyclus
GBIF
Animalia
Architaenioglossa
8
9
Mollusca
species
convexiusculus
Figs 4, 5, 8C
Cyclostoma (Cyclophorus) convexiusculum Pfeiffer, 1855: 104( typeloc.: Simonstown [Macgillivray]). Cyclophorus convexiusculusvar. minor Benson, 1856: 438( typeloc.: Table Mountain [Layard]). Chondrocyclus convexiusculus– Kobelt 1902: 230. — Connolly 1939: 536. — Herbert & Kilburn 2004: 92.
Diagnosis Shell small, depressed, lenticular; protoconch mammillate and tilted; periostracum with axial costae developing at the periphery broad triangular flanges each terminating in a long, hair-like spine; operculum flattened, exterior portion shallowly concave, with step-shaped multispiral lamella terminating in a long solid fringe; radula with three large cusps on second lateral tooth.
Etymology The specific name is derived from the Latin ‘ convex’, meaning ‘arched or vaulted’.
Type material examined Syntypes SOUTH AFRICA– Western Cape• 3 specimens; syntypesof Cyclostoma (Cyclophorus) convexiusculum Pfeiffer, 1855( Fig. 4A); Simons Bay; [Mrs] Cumingleg.; NHMUK 20120231. Other material examined SOUTH AFRICA– Western Cape• 6 specimens; Cape Peninsula, Simonstown; 34.1912° S, 18.4211°E; M. Connollycoll.; NMSA 2777• 2 specimens; same collection data as for preceding; ex. M. Connollycoll.; NMSA A8004• 11 specimens; Cape Town, 2.8 kmsouth of Miller’s Point, forest in a depression with a few invasive trees ( Eucalyptusand Port Jackson), steep slope with rocks and root buttresses; 34.2507° S, 18.4729° E; 25 Jun. 2011; R. Danielsleg.; thick and moist leaf litter, about a week of rain before collection; ELMD16879• 11 specimens; same collection data as for preceding; ELM W3636• 1 specimenin ethanol; same collection data as for preceding; NHMUK 20120276• 40 specimens; same collection data as for preceding; 1 Feb. 2012; R. Danielsleg.; ELMD16880• 17 specimens; same collection data as for preceding; ELM W3637• 3 specimens; same collection data as for preceding; NHMUK 20120277• 2 specimens; same collection data as for preceding; NMW.Z.2012.065.00007• 5 specimens; DuToits Kloof, Donkerkloof, patch of Southern Afrotemperate forestin steep ravine; 33.7536° S, 19.0696° E; 462 ma.s.l.; 7 Aug. 2014; M. Coleleg.; ELMD17970• 1 specimen; same collection data as for preceding; ELM W3891• 26 specimens; Kogelberg Nature Reserve, small patch of Southern Afrotemperate forestnear Leopards Gorgewaterfall; 34.3409° S, 18.9407°E; 312 ma.s.l.; 12 Aug. 2014; M. Coleleg.; ELMD17955• 22 specimens; same collection data as for preceding; ELMW03876• 22 specimens; Kogelberg Nature Reserve, Oudebosch, patch of Southern Afrotemperate forestin kloof with Oudebos River; 34.3337° S, 18.9487°E; 260 ma.s.l.; 12 Aug. 2014; M. Coleleg.; ELMD17975• 25 specimens; same collection data as for preceding; ELMW03877.
Description SHELL ( Fig. 4B–D). Small, depressed, lenticular, adult diameter 3.97–5.18 mm, height 2.29–3.20 mm, diameter:height 1.59–1.88 (n = 21). Spire little exserted, apex mammillate and tilted ( Fig. 4A, C). Embryonic shell ( Fig. 4E) approx. 2.25 whorls, microscopically malleate, sculpture strongest on earliest part, junction between embryonic shell and teleoconch evident with development of axial costae and threads on teleoconch. Teleoconch comprising 2.25 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 lacquerlike with lamellate axial costae at regular intervals, 44–61 (n = 16) on last whorl, developing at periphery broad triangular flanges terminating in a long, hair-like spine ( Figs 4F, 8C); intervals between costae with 3–5 indistinct microscopic axial threads. Shell translucent glossy honey-brown or creamy-white when fresh. Fig. 4. Chondrocyclus convexiusculus( Pfeiffer, 1855). A. Syntype (NHMUK 20120231). B–K. ELM W3636. B. Dorsal view. C. Aperture view. D. Ventral view. E. Protoconch. F. Detail of axial lamellae of periostracum. G. Portion of radula. H–I. Operculum. J–K. Penis, lateral and dorsal views, showing position on head. Scale bars: A, C = 3 mm; B, D = 2 mm; E = 200 µm; F, J–K = 500 µm; G = 50 µm; H–I = 1 mm. LIVING ANIMAL. Head, tentacles and snout dark grey; underside of foot white. OPERCULUM ( Fig. 4H–I). Duplex, outer portion concave, consists of multispiral lamella with almost five whorls, each step-shaped; the growing edge of the lamellar blade angular and is more or less perpendicular to disc where it is attached; long fringe of fused bristles emanates from outer side of lamellar blade and curves upwards and outwards forming a furrow between fringe and lamellar blade partially covered by top edge of lamellar blade which curves outwards; top edge of lamella projects above fringe; fringe of each whorl fused to lamella of following whorl. RADULA ( Fig. 4G). Rachidian with five cusps, central cusp approx. twice as long as two on either side of it; first and second lateral tooth each with four cusps and a swelling representing the fifth cusp, first three cusps (from centre) increasing in size and fourth considerably smaller. PENIS ( Fig. 4J–K). Shaft more-or-less cyclindrical with slightly swollen distal end and a short intromittent organ.
Distribution and habitat Western Cape, mountains of the CapePeninsula and north-south running mountains to the east of the CapeFlats. Inland populations appear to be bounded by the upper Breede River valley and coastal populations by the relatively low-lying Agulhas Plain ( Fig. 5). There are no records from the Riviersonderend Mountains. Western CapeAfrotemperate forest ( von Maltitz et al.2003), very small patches in sheltered ravines; in leaf-litter.
Remarks Connolly (1929)distinguished this species from C. alabastrison the basis of the second lateral tooth of the radula, that of C. convexiusculushaving three large cusps and C. alabastristwo. This is confirmed by comparing Fig. 4Gand Fig. 7F. There are also differences in the periostracum and operculum discussed under C. alabastris.The molecular analyses placed C. convexiusculusand C. alabastrisin different clades ( Fig. 1).
2429182689
NHMUK
Cuming
South Africa
Simons Bay
8
9
NHMUK 20120231
3
Western Cape
syntype
2429182836
NMSA
M. Connolly
South Africa
-34.1912
Simonstown
6
18.4211
Peninsula
8
9
NMSA 2777
6
Western Cape
2429182583
NMSA
M. Connolly
South Africa
-34.1912
Simonstown
6
18.4211
Peninsula
8
9
A8004
2
Western Cape
2429182588
2011-06-25
ELM
R. Daniels
South Africa
Town
-34.2507
Port Jackson
6
18.4729
Miller's Point
8
9
11
Western Cape
2429182694
[594,1380,1316,1342]
2011-06-25
ELM
R. Daniels
South Africa
Town
-34.2507
Port Jackson
6
18.4729
Miller's Point
8
9
W3636
11
Western Cape
2429182582
[189,1141,1352,1378]
2011-06-25
NHMUK
R. Daniels
South Africa
Town
-34.2507
Port Jackson
6
18.4729
Miller's Point
8
9
NHMUK 20120276
1
Western Cape
2429182728
2012-02-01
ELM
R. Daniels
South Africa
Town
-34.2507
Port Jackson
6
18.4729
Miller's Point
8
9
40
Western Cape
2429182655
2012-02-01
ELM
R. Daniels
South Africa
Town
-34.2507
Port Jackson
6
18.4729
Miller's Point
8
9
W3637
17
Western Cape
2429182639
2012-02-01
NHMUK
R. Daniels
South Africa
Town
-34.2507
Port Jackson
6
18.4729
Miller's Point
8
9
NHMUK 20120277
3
Western Cape
2429182592
[456,1378,1459,1486]
2012-02-01
NMW
R. Daniels
South Africa
Town
-34.2507
Port Jackson
6
18.4729
Miller's Point
8
9
2
Western Cape
2429182572
2014-08-07
ELM
M. Cole
South Africa
DuToits Kloof
462
-33.7536
Southern Afrotemperate forest
6
19.0696
Donkerkloof
8
9
5
Western Cape
2429182637
2014-08-07
ELM
M. Cole
South Africa
DuToits Kloof
462
-33.7536
Southern Afrotemperate forest
6
19.0696
Donkerkloof
8
9
W3891
1
Western Cape
2429182707
2014-08-12
ELM
M. Cole
South Africa
Kogelberg Nature Reserve
312
-34.3409
Leopards Gorge
6
18.9407
Southern Afrotemperate forest
8
9
26
Western Cape
2429182847
2014-08-12
ELM
M. Cole
South Africa
Kogelberg Nature Reserve
312
-34.3409
Leopards Gorge
6
18.9407
Southern Afrotemperate forest
8
9
22
Western Cape
2429182647
2014-08-12
ELM
M. Cole
South Africa
Kogelberg Nature Reserve
260
-34.3337
Southern Afrotemperate forest
6
18.9487
Oudebosch
8
9
22
Western Cape
2429182595
[378,1177,1744,1771]
2014-08-12
ELM
M. Cole
South Africa
Kogelberg Nature Reserve
260
-34.3337
Southern Afrotemperate forest
6
18.9487
Oudebosch
8
9
25
Western Cape