Afrorhytida kraussi kraussi ( Pfeiffer, 1846 )

Herbert, D. G. & Moussalli, A., 2010, Revision of the larger cannibal snails (Natalina s. l.) of southern Africa - Natalina s. s., Afrorhytida and Capitina (Mollusca: Gastropoda: Rhytididae), African Invertebrates 51 (1), pp. 1-1 : 89-95

publication ID

https://doi.org/ 10.5733/afin.051.0101

persistent identifier

https://treatment.plazi.org/id/110B87C2-FFDC-FF8B-D736-FA49FC86FB09

treatment provided by

Felipe

scientific name

Afrorhytida kraussi kraussi ( Pfeiffer, 1846 )
status

 

Afrorhytida kraussi kraussi ( Pfeiffer, 1846) View in CoL

Figs 10C View Fig , 54E View Fig , 55D, E View Fig , 61–63 View Fig View Fig View Fig , 64A–D View Fig , 65D View Fig

Helix kraussi: Pfeiffer 1846 c: 70 ; 1848: 197; Krauss 1848: 77, pl. 4, fig. 24; Reeve 1854 in 1851–54: sp. 1391. Type loc.: ‘ Outeniqua prom . bon. spei. (Krauss.)’, later given as ‘ In sylvis Outeniqua , provinc. George ’ by Krauss (1848).

Helix sturmiana Pfeiffer, 1853 a: 253 ; 1853 b: 150; 1854: 142; 1854 in 1853–60: 397, No 944, pl. 144, figs 3, 4; Reeve 1853 in 1851–54: sp. 1132; Pilsbry 1890 in 1890–91: pl. 36, figs 28, 29. Type loc.: originally unknown ( Cuming Coll’n ), later given as Delagoa Bay [southern Mozambique], but without justification (Pfeiffer 1878 in 1878–81: 62 as Macrocyclis View in CoL ).

Macrocyclis sturmiana: Pfeiffer 1878 in 1878–81: 62.

Helix (Acusta) kraussi: Tryon 1888: 50 , pl. 10, fig. 30.

Dorcasia kraussi: Pfeiffer 1879 in 1878–81: 187; Sturany 1898: 50; Pilsbry 1895 in 1893–95: 173.

Phasis sturmiana: Sturany 1898: 41 ; Pilsbry 1893 in 1893–95: 37.

Helix (Ampelita) sturmiana: Pfeiffer 1879 in 1878–81: 184.

Rhytida kraussi: Melvill & Ponsonby 1898: 170 (= sturmiana ).

Rhytida (Afrorhytida) kraussi: Möllendorff 1903: 63 , pl. 11, figs 5, 6.

Natalina kraussi: Connolly 1912: 94 View in CoL ; 1925: 122; 1939: 112, pl. 3, figs 8–10.

Natalina liliacea Preston, 1912: 17 View in CoL ; Connolly 1912: 95; 1939: 114. Type loc.: ‘Knysna Forest, Cape Colony’ [Cox]. Syn. n.

Natalina knysnaensis: Connolly 1939 View in CoL : text-fig. 9 (radula).

Natalina (Afrorhytida) kraussi: Bruggen 1970: 468 View in CoL .

Not Rhytida kraussi: Moss 1894: 25 , pl. 1 fig. 3; nor Rhytida Kraussii [sic]: Cooke 1895: 232 [= Nata vernicosa ( Krauss, 1848) View in CoL ].

Etymology: Named for Christian Ferdinand Friedrich Krauss (1812–91), the early German explorer-naturalist and later director of the natural history museum in Stuttgart, who wrote the first scientific work devoted to southern African molluscs ( Krauss 1848).

Identification ( Fig. 61 View Fig ): The shell of Afrorhytida k. kraussi is considerably less globose than that of A. burseyae sp. n. and typical (south-eastern) specimens of A. knysnaensis . In shell proportions and colour it most closely resembles A. trimeni , but in the present species the last adult whorl is generally less deep and has less distinct axial ribs.Additionally, in A. trimeni the radula has distinctively shaped inner lateral teeth and fewer marginal teeth (see below). The more lenticular shells of north-western specimens of A. knysnaensis are generally of a paler, somewhat yellowish or greenish hue and the radula of that species has more strongly developed inner marginal teeth and the outer lateral tooth rather than the penultimate one is the largest. In fresh specimens of A. k. kraussi the pinkish lilac sheen of the interior is also diagnostic.

Description: Shell generally lenticular, but proportions somewhat variable; adult shell comprising 4.0–4.5 whorls, the last frequently descending somewhat prior to aperture in adult specimens; base glossy, apical surface less so. Protoconch 4.5–5.0 mm in diameter, with distinct, relatively coarse axial riblets more or less throughout. Apical surface of teleoconch sculptured by close-set axial riblets, these becoming weaker and less well defined toward end of last adult whorl and on base; base also with traces of spiral liration; aperture subcircular to roundly ovate and somewhat obliquely descending; outer lip thin but not membranous (in adult), its basal portion and columella lip slightly thickened; upper part of columella lip weakly reflected; umbilicus relatively wide and not obscured to any appreciable degree by reflected columella lip.

Periostracum of fresh adult specimens usually predominantly brown, without a yellowish or greenish tinge, but young specimens sometimes paler and somewhat greenish; all specimens tending to fade and eventually becoming slightly yellowish; coloration generally uniform, but occasionally with slight axial variation in intensity. Underlying shell whitish, interior of aperture with a pale, but distinct pinkish lilac wash.

Dimensions: Largest specimen (NMSA W4748, Marloth Nat. Res.),diameter 28.4 mm, height 18.4 mm, but some specimens appear to be adult at diameter 21 mm; H:D of adults 0.48–0.67 (N=39).

Living animal ( Figs 55D, E View Fig ): Few specimens have been examined or photographed alive, but the coloration of the living animal is evidently variable.Head-foot of specimens from both forest and fynbos habitats in the Knysna–Tsitsikamma area (typical) generally shades of dark brown ( Fig. 55D View Fig ), usually darkest in neck region and tail, but with a conspicuous pale, dorsolateral, longitudinal stripe on each side of neck, extending backward from optic tentacle; sides of foot paler; optic tentacles dark grey-brown; pedal margin may be tinged with orange; mantle edge mostly dirty yellowish cream; lung wall usually heavily marked with black. Specimens from Grootvadersbosch ( Fig. 55E View Fig ), however, though similarly patterned, are primarily of an orange to reddish hue, frequently brightly so along the dorsal neck and pedal margin.

Radula ( Figs 64A–D View Fig ): Formula 1+(11–15)+(11–16) (N=5); length up to 22.5 mm, with 70–85 V-shaped rows of teeth, 3.2–4.3 rows/mm in adult. Rachidian cusp somewhat longer than its base-plate. Inner lateral teeth more or less parallel-sided, apically acuminate and differing little in size; outermost 3 or 4 lateral teeth considerably larger, with a stout elongate-quadrate base-plate and long, slender, gently curved, sharply pointed cusp; penultimate lateral larger than outermost one; precise shape and curvature of outer laterals somewhat variable between individuals. Innermost marginal tooth relatively large (0.50–0.75 length of outer lateral), the second and subsequent marginals very much smaller and essentially vestigial.

Distal genitalia ( Fig. 54E View Fig ): See generic description. Epiphallus 75 % or more of penis length, broadest near penis, tapering slowly toward vas deferens and merging smoothly therewith; occasionally with distinct greyish pigmentation; inner side of lumen wall (that adjacent to penis) with two strong folds with an intervening groove running entire length of epiphallus; remaining lumen wall with 2 or 3 low longitudinal ridges in thicken- ed portion nearer to penis, with a row of minute punctations (sometimes paired) in their intervals, these extending to penial end of epiphallus; punctations represent openings of slender diverticulae in epiphallus wall which are visible as striae in cut wall; lumen wall nearer to vas deferens smooth or with shallow ridges, but no punctations.

Spermatophore ( Figs 10C View Fig , 62 View Fig ): A single allospermatophore was found in a specimen from Grootvadersbosch (collected in mid October). It was situated in the upper vagina and free oviduct; the anterior half occupying almost the entire length of the free oviduct and the posterior half extending well down into the upper vagina, the opening of the bursa copulatrix duct more or less level with the middle of the spermatophore. Spermatophore itself S-shaped and twisted, approx. 20 mm in total length (straightened); anterior third slender and spinose; posterior two-thirds smooth, comprising a somewhat broader mid-piece, tapering to an acuminate tail.Anterior region somewhat quadrate in cross section, the angles on the convex surface set with a row of close-set, antler-like projections, each comprising a narrow stalk which divides into a branched array of 5– 8 sharp spines; these spinose ridges continue posteriorly to start of mid-piece, diminishing and disappearing soon thereafter; a third row of similar projections present on one side of head region, but this terminating abruptly, some distance prior to the other rows; concave surface of anterior half smooth, with angular margins, broadening on mid-piece. No obvious vent present in tail region, but concave wall of mid-piece evidently thin and perhaps representing rupture site for sperm release.

Type material: Holotype of Helix kraussi Pfeiffer, 1846 in Stuttgart Museum, now lost (cf. Herbert & Warén 1999), but illustrated by Connolly (1939: pl. iii, figs 8–10), diameter 20.7 mm [considerably smaller than the measurements given by Pfeiffer (1846 c) and Krauss (1848). Holotype of Helix sturmiana Pfeiffer, 1853 in BMNH (20080064), diameter 20.8 mm ( Fig. 61K View Fig ). Holotype of Natalina liliacea Preston, 1912 in ISNB MT/525059 (Dautzenberg Coll’n), diameter 20 mm, height 12.3 mm (the height of 16.5 mm given by

Preston is clearly an error) ( Figs 61A–C View Fig ); paratype in BMNH (1911.8.22.59), diameter 20.2 mm, height 12.65 mm (20.5 mm and 13.8 mm fide Connolly 1939).

Additional material examined (all NMSA unless otherwise indicated): SOUTH AFRICA: Langeberge: Marloth Nat. Res. (33.98975°S: 20.45439°E), Afrotemperate forest , A. Moussalli & D. Stuart-Fox, 23/ii/ 2005 (W4748) GoogleMaps ; Swellendam area, Langeberge Mts , northern side (33.967°S: 20.483°E), 1250 m, in collapsed mole-hill, V. Millard, i/2001 (V8788) GoogleMaps ; Tradoupas , approx. 10 km S of Barrydale (33.97660°S: 20.70311°E), 353 m, riparian indigenous forest/ fynbos, A. Moussalli, 26/viii/2006 (W4678) GoogleMaps ; Grootvadersbosch Nat. Res. (33.99595°S: 20.81288°E), 402 m, Afrotemperate forest , in leaf-litter, A. Moussalli & D. Stuart-Fox, 22/ii/2005 (W3350) GoogleMaps ; Grootvadersbosch Nat. Res. (33.99595°S: 20.81288°E), 402 m, Afrotemperate forest , in leaf-litter, A. Moussalli & D. Stuart-Fox, 22/ii/2005 (W3351) GoogleMaps ; Grootvadersbosch (33.983°S: 20.830°E) (W889); Grootvadersbosch Nat. Res. (33.98197°S: 20.83363°E), Afrotemperate forest , in leaf-litter under logs, D. Herbert & L. Davis, 13/x/2007 (W5803) GoogleMaps ; Langeberge, Lemoens Hoek Mts ( Grootberg ] (33.917°S: 20.867°E), K.H. Barnard ( SAMC A7244 View Materials ). Outeniekwaberge and Swartberge : Herbertsdale area, Cloetesberg, Cloetespas (33.92083°S: 21.76028°E), 375 m, dry fynbos, under rocks, M. Cunningham, 5/viii/2003 (W3207) GoogleMaps ; Herbertsdale area (34.04594°S: 21.88528°E), 360 m, K. Tolley, 28/xi/2005 (W4099) GoogleMaps ; Attakwasberge (33.82580°S: 21.9250°E), 560 m, montane fynbos, under rocks, M. Cunningham, viii/2003 (W4780) GoogleMaps ; Swartberg Pass, between Prince Albert and Oudtshoorn (33.35°S: 22.05°E), K.H. Barnard ( BMNH 1937 . 12.30.1380); Engelseberg summit (33.86940°S: 22.13420°E), 1500 m, montane fynbos, under rocks, M. Cunningham, viii/2003 (W3211) GoogleMaps ; Montague Pass, north of George (33.89142°S: 22.42912°E), 620 m, montane fynbos, under rocks, A. Moussalli & D Stuart-Fox, 11/iii/2005 (W4849) GoogleMaps ; Prince Albert, Meiringspoortberg (33.4167°S: 22.5500°E), 1850–2000 m, K.H. Barnard ( NMH 1937.12.30.1344). Coastal southern Cape (Wilderness – Tsitsikamma – St Francis Bay ): Wilderness area (33.983°S: 22.583°E), indigenous forest, J.S. Taylor, 1964/5 (V5196, V6578, V6579, V6580); Wilderness, Kaaimansrivier (33.983°S: 22.583°E), J.S. Taylor, 21/xi/1964 (V5198) GoogleMaps ; Wilderness, Touwsrivier (33.983°S: 22.583°E), J.S. Taylor, 19/ix/1964 (V5197) GoogleMaps ; Wilderness Nat. Park, Touwsrivier (33.98348°S: 22.60949°E), indigenous forest, deep in leaf-litter, A. Moussalli & D. Stuart-Fox, 13/iii/2005 (W4784) GoogleMaps ; Sedgefield (34.0333°S: 22.7833°E), C. Vernon, 15/iii/ 1985 ( ELM D11079 View Materials ) GoogleMaps ; 4 km west of Keurhoek (33.95191°S: 22.91220°E), indigenous forest, A. Moussalli & D. Stuart-Fox, 12/iii/2005 (W4747) GoogleMaps ; Knysna Forest (holotype Natalina liliacea ) (34.033°S: 23.033°E) ( ISNB / MT/525059); ditto, MacAndrew coll’n, ex Preston, 19/vi/1911 ( BMNH 1563 ) GoogleMaps ; Knysna, Featherbed Nat. Res. (34.08040°S: 23.06361°E), indigenous forest, in leaf-litter, A. Moussalli, 22/viii/2006 (W4671) GoogleMaps ; Knysna, Diepwalle region, vicinity of King Edward VIII tree (33.95656°S: 23.15256°E), 423 m, indigenous forest, in deep leaf-litter, A. Moussalli & D. Stuart-Fox, 12/iii/2005 (W4845) GoogleMaps ; Knysna area, Harkerville Nat. Res., Kranshoek Trail (34.08713°S: 23.22577°E), 29 m, Afrotemperate forest , under rock, A. Moussalli, 21/viii/ 2006 (W4667) GoogleMaps ; Nature’s Valley, Salt River area (33.983°S: 23.533°E), indigenous forest, D. Herbert, 19/ix/ 2003 (W1178) GoogleMaps ; Tsitsikamma Mountain , Formosa Peak Trail (33.86390°S: 23.70190°E), fynbos, under rocks, M. Cunningham, 05/iii/2003 (W3212) GoogleMaps ; Baviaanskloof wilderness area, Kougaberge (33.67492°S: 24.20997°E), fynbos, under stones, D. Herbert, 10/x/2000 (V8621) GoogleMaps ; Van Staden’s River (ca 33.75°S: 25.20°E), 1891 (V7799); Lady’s Slipper Nat. Res., Van Stadensberg, (33.89091°S: 25.26659°E), montane fynbos, amongst rocky outcrop after fire, A. Moussalli & D. Stuart-Fox, xii/2005 (W6176) GoogleMaps ; ditto (33.88941°S: 25.27019°E), 560 m, Kouga grassy sandstone fynbos with abundant Watsonia , in pockets of fine dark soil on rock outcrops, D. Herbert, L. Davis & M. Cole, 08–057, 22/ix/2008 GoogleMaps (W6426).

Additional literature records (material not seen): Langeberge, Zuurbrak Peak (33.85°S: 20.65°E), 1400 m (Connolly 1939); Swartberg Pass, Platberg (33.317°S: 22.030°E), ca 1550 m, under stones, 5–6/i/1951 (Bruggen 1970); Outeniqua, George District, Krauss (Connolly 1939); Outeniqua Mts, Robinson Pass (33.8830°S: 22.0167°E), 615 m, under stones, 7/i/1951 (Bruggen 1970); Montagu Pass, Doorn River (33.883°S: 22.430°E), Haughton (Connolly 1939); Knysna (34.033°S: 23.033°E), Power (Connolly 1939); Plettenberg Bay, Keurbooms River bush (34.017°S: 23.417°E), Barnard (Connolly 1939, as N. liliacea ); Kromme River (? Kromrivier, Kareedouberge, 33.99°S: 24.30°E), Moran (Connolly 1939).

Rejected literature records: Grahamstown (33.300°S: 26.533°E), Miss Glanville, fide Layard (Connolly 1939); Great Fish Point area, Tharfield farm (33.5500°S: 27.0167°E), Miss Bowker (Connolly 1939).

Distribution ( Fig. 63 View Fig ): Endemic to the south-central regions of the Cape, from the western Langeberge in the west, eastwards to Van Stadensberg in the St Francis Bay area, from the coastal hinterland through the Outeniekwaberge and reaching the Groot Swartberge inland of the Little Karoo; from low altitudes near the coast to 2000 m in the Groot Swartberge. Literature records from further east (Grahamstown and Great Fish Point) are almost certainly incorrect, despite being recorded by Connolly (1939). More probably they refer to specimens of Afrorhytida knysnaensis or A. trimeni . For most of its range,

A. kraussi is the only Afrorhytida present, but there is possible sympatry with both A. knysnaensis and A. trimeni in the greater Port Elizabeth area.

Habitat: Evidently occurs at low density in a wide variety of habitats from southern Afrotemperate forest to sandstone fynbos at higher altitudes in the mountains of the Cape Fold Belt; in leaf-litter and under logs in forest habitats, and under rocks, amongst clumps of vegetation and in pockets of soil on rock outcrops in fynbos habitats.

Notes: Shells vary considerably in shape, size and umbilical width. Those from fynbos habitats at higher altitudes tend to be smaller, whilst those from isolated forests in the west (e.g., Grootvadersbosch) tend to be largest. The latter also have conspicuously more red pigmentation on the head-foot and furthermore appear to constitute a genetically distinct lineage ( Moussalli et al. 2009). Similarly, Tolley and Burger (2007) have also shown that the Grootvadersbosch population of the dwarf chameleon Bradypodion damaranum (Boulenger, 1887) is genetically distinct from the remaining population in the Outeniekwa–Tsitsikamma region. The Grootvadersbosch forest is also home to two narrowly endemic subulinid land snails, Euonyma barnardi Connolly, 1929 and E. decipiens Connolly, 1929 .

Synonymy: Melvill and Ponsonby (1898) and Connolly (1912, 1939) treated Helix sturmiana Pfeiffer, 1853 as a synonym of the present species. The holotype originated from the Cuming collection and was of unknown provenance, but Pfeiffer later cited Delagoa Bay (environs of Maputo, Mozambique), though without explanation (Pfeiffer 1878 in 1878–81). Since no Afrorhytida species are known from north of E. Cape, this is without doubt erroneous. The holotype is almost identical in shape to specimens of A. kraussi from the Wilderness area (compare Figs 61J and 61K View Fig ) and it is quite possible that early collectors could have obtained material from this region. We concur with prior authors in treating Helix sturmiana Pfeiffer, 1853 as a synonym of A. kraussi .

Connolly (1939) correctly noted that Natalina liliacea Preston, 1912 was less globose than [typical] specimens of Afrorhytida knysnaensis , but it is puzzling that he did not compare it with A. kraussi , particularly given that the localities he cited for N. liliacea overlap extensively with those he gave for A. kraussi . We consider that the pinkish lilac blush typically seen in the aperture of N. liliacea (and from which the name derives) is a character likewise present in fresh specimens of A. kraussi kraussi .Although Pfeiffer (1846 c) did not mention this in his original description of Helix kraussi , when discussing the species Krauss himself stated ‘Die Mündung selbst ist be dem kleinen und wohlerhalten Exemplar blass violett’ [‘The aperture itself of the small and well preserved specimen is pale violet’] ( Krauss 1848: 77). Connolly indicated that the shell of N. liliacea was ‘prone to assume a distinct lilac hue in rather weather-worn condition’ indicating that he misinterpreted the origin of the species name which relates to a feature of fresh rather than weather-worn shells. Since we can find no characters by which these two nominal taxa can be distinguished, we place Natalina liliacea Preston, 1912 in synonymy with Afrorhytida kraussi kraussi . The type localities (Knysna and the George district respectively) are not far distant (<60 km apart), and a forested habitat is specifically mentioned for both.

Conservation: Afrorhytida kraussi kraussi occurs over an extensive area of the southern Cape (E–=W distance approx. 450 km) and is known to occur in a number of formally protected areas. These include both low altitude forest habitats as well as montane sandstone fynbos. This notwithstanding, fynbos habitats in much of the central Cape Fold Belt are subject to aggressive invasion by alien plants (pine and hakea) which threatens large-scale habitat transformation and degradation ( Cowling et al. 2009). The potentially distinct western lineage appears to be restricted to isolated forest patches of limited extent and is likely to meet the criteria for red-listing on account of its narrow range, should this eventually be shown to be a distinct taxon.

NMSA

KwaZulu-Natal Museum

SAMC

Iziko Museums of Cape Town

ELM

East London Museum

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Stylommatophora

Family

Rhytididae

Genus

Afrorhytida

Loc

Afrorhytida kraussi kraussi ( Pfeiffer, 1846 )

Herbert, D. G. & Moussalli, A. 2010
2010
Loc

Natalina kraussi: Connolly 1912: 94

CONNOLLY, M. 1912: 94
1912
Loc

Natalina liliacea

PRESTON, H. B. 1912: 17
CONNOLLY, M. 1912: 95
1912
Loc

Rhytida (Afrorhytida) kraussi: Möllendorff 1903: 63

MOLLENDORFF, O. F. & VON 1903: 63
1903
Loc

Dorcasia kraussi:

STURANY, R. 1898: 50
1898
Loc

Phasis sturmiana:

STURANY, R. 1898: 41
1898
Loc

Rhytida kraussi: Moss 1894: 25

COOKE, A. H. 1895: 232
MOSS, W. 1894: 25
1894
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