Nata vernicosa ( Krauss, 1848 ), Krauss, 1848

David G. Herbert & Adnan Mousalli, 2016, Revision of the dwarf cannibal snails (Nata s. l.) of southern Africa — Nata s. s. and Natella (Mollusca: Gastropoda: Rhytididae), with description of three new species, Zootaxa 4094 (1), pp. 1-67: 33-35

publication ID

http://doi.org/10.11646/zootaxa.4094.1.1

publication LSID

lsid:zoobank.org:pub:E5F1E766-687D-4B00-974B-8D7939DC66A0

DOI

http://doi.org/10.5281/zenodo.5615852

persistent identifier

http://treatment.plazi.org/id/03E687FC-E02D-D765-FF1A-11FA0A5B9FD9

treatment provided by

Plazi

scientific name

Nata vernicosa ( Krauss, 1848 )
status

sensu lato

Nata vernicosa ( Krauss, 1848)   sensu lato  

Figure 24 View FIGURE 24

Helix vernicosa Krauss, 1848: 76   , pl. 4, fig. 23. Pfeiffer, 1849: 93. Reeve, 1851: sp. 198, pl. 43. Morelet, 1889: 19. Herbert & Warén, 1998: 235. Type loc.: ‘ in terra natalensi ’ [Wahlberg].

Helix vernicosa   β. minor Pfeiffer, 1853: 95   . Type loc.: ‘ Natal Africae meridionalis ’.

Helix (Pella) vernicosa   — Pfeiffer, 1879 in 1878 –1881: 102.

Elaea vernicosa   — Tryon, 1885: 130, pl. 28, figs 52–54 [as E. verrucosa   [sic] in plate legend].

Elaea vernicosa   var. minor   — Tryon, 1885: 131.

Helix (Macrocyclis) caenotera Melvill & Ponsonby, 1892 b: 238   , pl. 13, fig. 2. Type loc.: 'Tharfield', E. Cape [Dr Schönland].

Helix (Macrocyclis) liparoxantha Melvill & Ponsonby, 1892 b: 238   , pl. 13, fig. 3. Type loc.: 'Maritzburg' [H.C. Burnup].

Natalina caenotera   —Pilsbry, 1893 in 1892–1893: 135. Melvill & Ponsonby, 1898 b: 170. Connolly, 1912: 92.

Natalina liparoxantha   —Pilsbry, 1893 in 1892–1893: 135. Melvill & Ponsonby, 1898 b: 170. Connolly, 1912: 96.

Natalina vernicosa   —Pilsbry, 1893 in 1892–1893: 135. Sturany, 1898: 31. Connolly, 1912: 97.

Natalina chaplini Melvill & Ponsonby, 1894: 91   , pl. 1, fig. 3. Melvill & Ponsonby, 1895: 165, pl. 12, figs 5, 5b. Melvill & Ponsonby, 1898 b: 170. Sturany, 1898: 31. Connolly, 1912: 92. Type loc.: 'Karnachs' [?=Kamesh], near Port Elizabeth, E. Cape [J. Crawford].

Rhytida kraussi   [non Pfeiffer, 1846]— Moss, 1894: 25, pl. 1, fig. 3.

Rhytida Kraussii   [sic] [non Pfeiffer, 1846]— Cooke, 1895: 232, fig. 139.

Macrocyclis coenotera   [sic]— Sturany, 1898: 32.

Macrocyclis liparoxantha   — Sturany, 1898: 33.

Natalina caffrula   [non Melvill & Ponsonby, 1898]— Sturany, 1898: 32. Germain, 1935: 5: Haas, 1936: 18 (in part, Umfolozi).

Rhytida vernicosa   — Melvill & Ponsonby, 1898 b: 170.

Rhytida (Macrocycloides) vernicosa   — Möllendorff & Kobelt, 1903, in 1903 –1905: 57, pl. 10, figs 12–14. Kobelt, 1909: 53.

Rhytida (Macrocycloides) chaplini   — Möllendorff & Kobelt, 1903, in 1903 –1905: 58, pl. 10, fig. 15–17. Kobelt, 1909: 53.

Rhytida (Macrocycloides) liparoxantha   — Möllendorff & Kobelt, 1903, in 1903 –1905: 58, pl. 10, fig. 18. Kobelt, 1909: 53.

Rhytida (Macrocycloides) coenotera   [sic]— Möllendorff & Kobelt, 1903, in 1903 –1905: 59, pl. 10, fig. 19. Kobelt, 1909: 53.

Natalina vernicosa   var. minor   — Connolly, 1912: 98.

Nata vernicosa   — Watson, 1934: 161. Connolly, 1939: 99, pl. 4, figs 4, 5, text fig. 6. Zilch, 1959 – 60: 554, fig. 1936. Bruggen, 1966: 376, fig. 54. Bruggen, 1967: 29. Bruggen, 1969: 37. Bruggen, 1970: 468. Bruggen, 1978: fig. 3 i. Bruggen, 1985: 286. Bruggen & Appleton, 1977: 32. Richardson, 1989: 45. Herbert, 1991: 11. Herbert & Kilburn, 2004: 219.

Nata liparoxantha   — Connolly, 1939: 101, pl. 3, figs 4–6. Richardson, 1989: 46.

Nata minor   — Connolly, 1939: 100, pl. 2, figs 9–11. Richardson, 1989: 46.

Helix (Nata) liparoxantha   — Bruggen, 1967: 29 [syn. nov. of Nata vernicosa   ]

Nata caerotera   [sic]— Richardson, 1989: 46.

Nata chaplini   — Richardson, 1989: 46.

Not Rhytida vernicosa   — Binney, 1879: 355 pl. 14, fig. 1. Binney, 1884: 82, pl. 17, fig. L [= Nata dumeticola   ].

The taxonomy of Nata vernicosa   is complex and confusing. Connolly (1939) provided the first revisionary comment on the species and noted that the E. Cape taxa Helix caenotera Melvill & Ponsonby, 1892   and Natalina chaplini Melvill & Ponsonby, 1894   were inseparable from Nata vernicosa   and thus considered them to be junior synonyms thereof. He treated Helix liparoxantha Melvill & Ponsonby, 1892   from KwaZulu-Natal as a distinct species, also referring it to Nata   , as had Watson (1934). Connolly observed, however, that although N. liparoxantha   attains a slightly larger size and has somewhat weaker axial sculpture than N. vernicosa   , it may in fact represent the same species. Pfeiffer’s N. vernicosa   var. minor   he considered to be another distinct species with a smaller, smoother shell. Subsequently, Bruggen (1967: 29) placed N. liparoxantha   in synonymy with N. vernicosa   , and later ( Bruggen 1985) suggested that N. vernicosa   might be considered a single wide-ranging and conchologically variable species encompassing all the taxa referred to Nata   s.s. by Connolly (1939) [see Introduction], noting at the same time that more conchological and anatomical information was needed.

While the availability of additional material has enabled us to establish that Nata   s.s. genuinely does encompass several distinct, highly genetically divergent species, circumscription of N. vernicosa   itself has proven more difficult. In recent years, as a practical solution, material that was not clearly referable to any of the other species has been identified as N. vernicosa   s.l., including N. liparoxantha   and N. minor   (both sensu Connolly, 1939   ), as for example in Herbert & Kilburn (2004). This, however, includes specimens exhibiting considerable variation in conchological characters, ranging from low, discoidal specimens virtually devoid of axial riblets, to globose-lenticular (deep-whorled) specimens with strong, axial riblets. From an anatomical perspective, this material exhibits no distinctive characters or consistent patterns of variation in either the radula or the distal genitalia that point to there being more than one species involved. Nonetheless, closer scrutiny of the greater amount of material now available has enabled us to identify within N. vernicosa   s.l. a separate, consistently smooth-shelled species that is geographically circumscribed and for the most part allopatric. This we describe below as Nata erugata   sp. nov. To date, only a single specimen ( NMSA W 3343, from Mt Sheba, Mpumalanga) of this species has been included in the molecular work (see Fig. 1 View FIGURE 1 ). While this specimen clustered as the most basally divergent individual in the N. vernicosa   clade ( Moussalli & Herbert 2016), additional material spanning the full range of the species will need to be included in future studies.

The remaining Nata vernicosa   s.l. material, however, continues to be problematic. Although highly variable in conchological features, we have been unable to discern any clear and consistent patterns in shell morphology that do not seem to intergrade. This variation intergrades both across the landscape and often also at individual localities, in an evidently seamless manner and it encompasses the variation exhibited by all the nominal taxa currently considered to be synonyms of N. vernicosa   . The extent of this variation, both between and within populations of N. vernicosa   , however, emphasises the significance of the morphological consistency underpinning N. erugata   sp. nov. If further cryptic species are present within N. vernicosa   , the most promising option for their discovery is likely to lie in molecular studies of a phylogeographic nature. Thus even though we have identified a new species amidst the confusion that has long surrounded N. vernicosa   s.l., we are still left with a morphologically diverse assemblage that requires further study using additional techniques.

Type material of Helix vernicosa:   Connolly (1939) stated that the ‘type’ of Helix vernicosa Krauss, 1848   was in the Stuttgart Museum and gave its dimensions as ‘diam. 14.8 x 12.0; alt. 7.6 mm’. Krauss, however, gave the dimensions as ‘diam. 5 x 4, alt. 3.3 lines’ (= 11.28 x 9.02, alt. 7.44 mm) 1. The Stuttgart specimen which Connolly considered to be the type was thus both significantly larger and more depressed than the material seen by Krauss (H:Dmax = 0.514 vs. 0.660). Connolly’s reason for considering this to be the type was not stated and evidently it was an unjustified assumption.

In the SMNH, which contains much original Wahlberg material, there is a lot containing four specimens that Herbert & Warén (1999) treated as possible paralectotypes of Helix vernicosa   ( SMNH 4965), believing Connolly’s discussion of ‘the type’ to constitute a lectotype designation. Since the latter was evidently unjustified on the grounds of the specimen’s dimensions and proportions, the type status of the SMNH specimens needs to be reevaluated. The largest specimen is again larger and more depressed than the Krauss material (max. diameter 13.3 mm; H:Dmax 0.586) and thus unlikely to have been seen by Krauss. However, in his remarks following the Latin description of Helix vernicosa, Krauss   stated that ‘the largest specimens were more costulate than the younger and as a result slightly semi-gloss.….the ribs are rather sharply raised and close-set…..’, and these comments apply well to the three remaining specimens in this SMNH lot. The two largest of these have crisp, close-set riblets and are lustreless, while the third one is smaller (younger) and has weaker riblets and is more glossy. These two larger lustreless specimens are relatively deep-whorled shells, the proportions of which fit well with measurements given by Krauss and with his original illustration [H:Dmax 0.676 and 0.670 compared with 0.660 for Krauss’s dimensions and 0.659 for his figure]. They are somewhat smaller than the measurements given by Krauss (Dmax 10.2 and 9.7, compared with 11.28 given by Krauss, but a difference of ± 10 % for the larger of the two is perhaps an acceptable error margin, allowing for differences in measuring methods.

The remaining smaller, more glossy shell ( Fig. 24 View FIGURE 24 M– O) fits Pfeiffer’s description ‘ costulis superficiei obsoletioribus ’ for his variety β. minor (Pfeiffer 1853)   , since its sculpture is very much weaker than in the other specimens. It was redescribed in more detail and figured by Connolly (1939) and Herbert & Warén (1999) considered that it may justifiably be considered the lectotype for Pfeiffer’s variety minor   .

Since it is important to clarify which taxon is actually represented by the name Helix vernicosa   (see below), it is necessary that a lectotype be designated. In light of the above observations, we select the larger of the two deepshelled, strongly ribbed specimens as the lectotype ( Fig. 24 View FIGURE 24 A–C). It was collected by Wahlberg in Natal, its dimensions and proportions are similar to those cited in the original description, it closely resembles the original figure and it matches the additional descriptive comments provided by Krauss.

Type material of synonyms: Lectotype of Helix (Macrocyclis) caenotera Melvill & Ponsonby, 1892   (designated Connolly 1912: 92) in NHMUK (1911.8.8.8) ( Fig. 24 View FIGURE 24 G–I), diameter 17.0 mm (the original description mentioned six specimens, but the whereabouts of the other five is not known). Lectotype of Helix (Macrocyclis) liparoxantha Melvill & Ponsonby, 1892   (designated Connolly 1912: 96) in NHMUK (1911.8.8.7) ( Fig. 24 View FIGURE 24 D–F), diameter 18.0 mm; the original description mentioned four specimens, thus three paralectotypes may also exist, two of these may be specimens in the Melvill-Tomlin Collection ( NMW. 1958.158) collected by H.C. Burnup in Port Shepstone [Rowson pers. comm., xii/ 2015]. Lectotype of Natalina chaplini Melvill & Ponsonby, 1894   (designated Connolly 1912: 92) in NHMUK (1911.8.8.9) ( Fig. 24 View FIGURE 24 J–L), diameter 10.4 mm, label gives locality as 'Cape Colony', but original description states 'Karnachs, near Port Elizabeth (J. Crawford)', (the original description mentioned three specimens, but the whereabouts of the other two is not known).

1. In the foreword to Krauss (1848) he stated that the measurements given were in ‘Pariser Zollen und linien’. [1.0 Paris ligne = 2.256 mm].

NMSA

KwaZulu-Natal Museum

SMNH

Saskatchewan Museum of Natural History

NHMUK

Natural History Museum, London

NMW

Naturhistorisches Museum, Wien

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Pulmonata

Family

Rhytididae

Genus

Nata

Loc

Nata vernicosa ( Krauss, 1848 )

David G. Herbert & Adnan Mousalli 2016
2016
Loc

Nata caerotera

Richardson 1989: 46
1989
Loc

Nata chaplini

Richardson 1989: 46
1989
Loc

Helix (Nata) liparoxantha

Bruggen 1967: 29
1967
Loc

Nata liparoxantha

Richardson 1989: 46
Connolly 1939: 101
1939
Loc

Nata minor

Richardson 1989: 46
Connolly 1939: 100
1939
Loc

Nata vernicosa

Herbert 2004: 219
Herbert 1991: 11
Richardson 1989: 45
Bruggen 1985: 286
Bruggen 1977: 32
Bruggen 1969: 37
Bruggen 1967: 29
Bruggen 1966: 376
Connolly 1939: 99
Watson 1934: 161
1934
Loc

Natalina vernicosa

Connolly 1912: 98
1912
Loc

Rhytida (Macrocycloides) vernicosa

Kobelt 1909: 53
1909
Loc

Rhytida (Macrocycloides) chaplini

Kobelt 1909: 53
1909
Loc

Rhytida (Macrocycloides) liparoxantha

Kobelt 1909: 53
1909
Loc

Rhytida (Macrocycloides) coenotera

Kobelt 1909: 53
1909
Loc

Natalina caenotera

Connolly 1912: 92
Melvill 1898: 170
1898
Loc

Natalina liparoxantha

Connolly 1912: 96
Melvill 1898: 170
1898
Loc

Natalina vernicosa

Connolly 1912: 97
Sturany 1898: 31
1898
Loc

Macrocyclis coenotera

Sturany 1898: 32
1898
Loc

Macrocyclis liparoxantha

Sturany 1898: 33
1898
Loc

Natalina caffrula

Haas 1936: 18
Germain 1935: 5
Sturany 1898: 32
1898
Loc

Rhytida vernicosa

Melvill 1898: 170
1898
Loc

Rhytida

Cooke 1895: 232
1895
Loc

Natalina chaplini

Connolly 1912: 92
Melvill 1898: 170
Sturany 1898: 31
Melvill 1895: 165
Melvill 1894: 91
1894
Loc

Rhytida kraussi

Moss 1894: 25
1894
Loc

Helix (Macrocyclis) caenotera

Melvill 1892: 238
1892
Loc

Helix (Macrocyclis) liparoxantha

Melvill 1892: 238
1892
Loc

Elaea vernicosa

Tryon 1885: 130
1885
Loc

Elaea vernicosa

Tryon 1885: 131
1885
Loc

Rhytida vernicosa

Binney 1884: 82
Binney 1879: 355
1879
Loc

Helix vernicosa

Morelet 1889: 19
Pfeiffer 1849: 93
Krauss 1848: 76
1848