Polygyratia polygyrata (Born, 1778)

Salvador, Rodrigo Brincalepe & Cavallari, Daniel Caracanhas, 2020, Taxonomy and distribution of enigmatic " helicoid " Polygyratia Gray, 1847 (Gastropoda, Stylommatophora), Zoosystematics and Evolution 96 (1), pp. 91-101 : 91

Polygyratia polygyrata (Born, 1778) Figs 1 , 2

Helix Polygyrata Born, 1778: 382; Wilhelm 1802: 356.

Helix polygyrata : Born, 1780: 373, pl. 14, figs 19-20; Schröter 1784: 266; Chemnitz 1786: 98, pl. 127, figs 1124-1125; Dillwyn 1817: 908; Férussac 1819: 4, pl. 69A, figs 7-9, pl. 69B, fig. 5); Férussac 1821: 40; Deshayes in Lamarck 1838: 98; Moricand 1846: 151, pl. 5, figs 1-3; Pfeiffer 1848: 405; Mörch 1852: 7; Reeve 1854: species 541, pl. 98; Hupé 1857: 12; Hidalgo 1870: 32; Hidalgo 1893: 80.

Helix polygyra [sic] Gmelin, 1788: 3624.

Helix Elongata Röding, 1798: 107.

Helix (Helicella) polygyrata : Moricand, 1836: 422.

Polygyra ? Polygyrata : Beck 1837: 23.

Polygyratia polygyrata : Gray 1847: 173; d’Orbigny 1849: pl. 19, figs 14-16; Mörch 1852: 7; Thiele 1931: 679; Zilch 1960: 603, fig. 2119; Richardson 1985: 262; Parkinson et al. 1987: pl. 13, fig. 6; Abbott 1989: 142, textfig.; Salgado and Coelho 2003: 172; Schileyko 2006: 1844, fig. 2359; Simone 2006: 247, fig. 946; Schileyko 2016: fig. 4; Breure and Araujo 2017: 121, figs 47D-F; Sei et al. 2017: table 9, fig. 5n; MolluscaBase 2019a; Salvador 2019: 95.

Ophiogyra polygyrata : Albers 1850: 91; Albers 1860: 94.

Polygyratia charybdis Mörch, 1852: 7.

Polygyratia (detrita.): Mörch 1852: 7.

Helix charybdis : Mörch 1852: 170.

Helix Charybdis : Hupé 1857: 12.

Helix (Anchistoma) polygyrata : Brauer 1878: 181.

Polygyra (Polygyratia) polygyrata : Tryon 1887: 111, 124, pl. 25, figs 72-74.

Polygyra (Polygyratia) polygyrata var. charybdis : Tryon 1887: 124.

Anchistoma polygyrata : Tryon 1887: pl. 25, figs 72-74.

Polygyratia (Polygyratia) polygyrata : Pilsbry 1894: 81, pl. 20, figs 37-38.

Polygyratia (Polygyratia) charybdis : Pilsbry 1894: 81.

Polygyratia polygyratia [sic] Gude 1920: 59.

Polygyratia polygyrata polygyrata : Morretes 1949: 163.

Polygyratia polygyrata charybdis : Morretes 1949: 163.

Polygyratia charybdis : Simone 2006: 247, fig. 945.

Type locality.

Unknown (Born, 1780); “Brazil” according to Schileyko (2006); restricted to Bahia state herein.

Type material.

NHMW-MO-14371, holotype (Fig. 1A ; see also Brauer 1878).

Common name.

Reported (and maybe given) by Born (1778), in German: "die Schnirkelscheibe". “Schnirkelschnecken” is a general term often applied to any member of family Helicidae , so the German name can be roughly translated to English as "discoid helix"; or, allowing for a broader interpretation, it could be translated as "ornate disc". However, using those names could bring unwanted confusion, because it would make the classification of P. polygyrata unclear by conflating it with Helicidae and disc snails (family Discidae ).

Férussac (1819), Deshayes (in Lamarck 1838) and Reeve (1854), as usual in their works, proposed vernacular names that were direct translations of the Latin name (then Helix polygyrata ): respectively, “hélice polygyre" and "many-whorled Helix ". While this name is somewhat descriptive, it is not distinct enough for a vernacular name. Abbott (1989) suggested a more appropriate name, although a rather clumsy one: "Brazilian gyrating snail". Therefore, we propose here to adopt a simpler, yet descriptive, common name, "gyre snail", returning to Born’s (1778) interpretation of a planispiral ornate spire and streamlining Abbot’s (1989) proposal.

Distribution.

Eastern Bahia state, Brazil (Fig. 3 ).

Specific occurrences.

Museum specimens: Pará state (likely mistaken, see below). Bahia state: Baía de Todos-os-Santos (Todos-os-Santos Bay), Cachoeira (road to Una), Canavieiras, Ilhéus, Itabuna, Itacaré, Itaparica, Olivença, Pimenteira, Salvador, Serra Grande, Uruçuca, Una, Una Biological Reserve. Literature data: Cachoeira ( Férussac, 1819, as “Caxoeira”). iNaturalist: Bahia state: São Sebastião do Passé. Internet: Bahia state: Ilhéus, Valença.

Habitat.

Atlantic Forest.

Diagnosis.

As for genus above.

Description.

Shell (Fig. 1 ) planispiral, multiwhorled. Spire typically slightly depressed, but often flat. Whorl profile markedly convex, with soft angulation marking borders of apical and umbilical regions; a central angulation on the body whorl can be seen in some specimens. Whorls closely packed together, regularly increasing in size. Body whorl bent abapically near the aperture. Presence of internal parietal (typically one) and palatal (typically two) lamellae on body whorl (Fig. 2 ; see also Suppl. material 1); lamellae short, disposed in two or three sets, positioned circa ⅓ and ⅔ of a whorl away from aperture. A different number of lamellae may be present in some specimens, which may have additional smaller lamellae or even lack one of the main three lamellae. Aperture rounded to D-shaped; callus may be present. Peristome lightly reflexed. Umbilicus very wide and deep. Sculpture: Protoconch of 2¼-2½ whorls, apparently smooth (typically eroded). Teleoconch sculpture by coarse growth lines that become coarser and more irregular towards aperture; often, growth lines acquire a papillose aspect. Colour: Shell predominantly chestnut brown, but often ochre. Some regions typically ochre: spiral band on adapical angulation of whorl (not always present); spire top (protoconch and first whorls); abapical region (excluding a chestnut coloured subsutural spiral band). Rarely, abapical (umbilical) portion of shell can be chestnut brown. Peristome white. Measurements: n = 26. H = 12.3 ± 0.9 mm (max 14.1, min 10.7); D = 43.5 ± 3.7 mm (max 56.7, min 38.2); W = 8¾ ± ⅓ (max 9½, min 8).

Material analysed.

Brazil. Uncertain locality: AMNH 43888 (3 sh, pre-1911, ex J.J. Crooke colln.); AMNH 43889 (2 sh, ex Steward colln.); AMNH 43890 (2 sh, pre-1891, ex J.C. Jay colln.); AMNH 53755 (1 sh, pre-1905, ex J.A. Constable colln.); AMNH 294063 (1 sh, pre-2001, col. Krassner, ex N.A. Katsaras colln.); ANSP 1450 (1 sh, pre-1886, ex A.D. Brown colln.); ANSP 23777 (1 sh, ex Swift colln.); ANSP 33049 (1 sh, pre-1865, ex T.B. Wilson colln.); ANSP 217111 (1 sh, ex Higgins colln.); ANSP 361998 (1 sh, ex Alfred University colln.); FMNH 165 (4 sh, pre-1893, ex Ward’s Natural Science Establishment colln.); FMNH 40632 (3 sh, pre-1924, ex W.F. Webb colln., ex G.K. Gude colln., ex Smith colln.); FMNH 57464 (2 sh, pre-1954, ex O. Park colln.); FMNH 62570 (1 sh, pre-1956, ex E.E. Hand colln., ex W.F. Webb colln.); FMNH 75810 (1 sh, pre-1951, ex J. Zetek colln., ex W.F. Clapp colln.); FMNH 100081 (1 sh, pre-1877, ex F. Button colln., ex J.G. Anthony colln.); FMNH 365269 (1 sh, ex CMNH coll., ex Ward’s Natural Science Establishment colln.); MNB unnumbered (3 sh, ex Linnaea colln., ex ZMB colln.); MNB unnumbered (1 sh); MNB unnumbered (1 sh); MNCN 15.05/39937 (4 sh, col. J.G. Hidalgo); MNZ M.233517 (1 sh, pre-1918, ex H.A. Suter colln. 5793); NHMD 615840 (1 sh, ex Lind colln., possibly ex A.M. D’A.G. Yoldi colln.); NHMD 615841 (1 sh); NHMD 615842 (possible holotype of Polygyratia charybdis , ex Lind colln., possibly ex A.M. D’A.G. Yoldi colln.); NHMD 615855 (1 sh, pre-1945, ex C.M. Steenberg colln.); NHMD 615856 (2 sh); NHMD 615857 (2 sh); NHMUK unnumbered (1 sh, pre-1952, ex J.E. Cooper colln. 2150); NHMUK unnumbered (2 sh, pre-1940, ex V.W. MacAndrew colln. 1563); NHMUK unnumbered (3 sh, pre-1941, ex B.R. Lucas colln. 2351); NHMUK unnumbered (2 sh, pre-1910, ex C.T. Trechmann colln. 2176); NHMUK unnumbered (1 sh, pre-1905, ex Blanford colln.); NHMUK unnumbered (3 sh, pre-1948, ex A.S. Kennard colln. 1824); NHMUK unnumbered (1 sh, pre-1991, ex “Mrs.” De Burgh colln. 1822); NHMUK unnumbered (1 sh, ex Connoly colln.); NHMW-MO-14371 (holotype; ex I.v. Born colln.); NHMW-MO-9215 (1 sh); NHMW-MO-72546 (2 sh); NHMW-MO-unnumbered (1 sh, pre-1930, ex A. Oberwimmer colln.); NHMW-MO-unnumbered (2 sh, v/1881); NHMW-MO-unnumbered (2 sh, ex G. Brandt colln.); MNCN 15.05/14101 (1 sh, col. Paz); RMNH.MOL.289966 (2 sh, pre-1942, ex H.C. Fulton colln.); RMNH.MOL.289967 (2 sh, pre-1895, ex Geological Museum of Wageningen University colln., ex ZMB colln., ex F.W. Zürcher colln., ex Linnaea colln.); SMF 26245 (1 sh, ex Lömel colln.); SMF 26246 (2 sh, ex K. Haskagen colln.); SMF 26247 (1 sh); SMF 26248 (1 sh, pre-1903, ex O.v.F. Moellendorf colln.); SMF 26249 (1 sh, pre-1876, ex O. Reinhardt colln., ex H.C. Küster colln.); SMF 26250 (1 sh, pre-1894, ex O. Boettger colln., ex Linnaea colln.); SMF 82611 (1 sh, pre-1928, ex Jetschin colln.); SMF 82612 (1 sh, pre-1893, ex K.L. Pfeiffer colln., ex Linnaea colln.); SMF 62613 (2 sh, pre-1905, ex C.R. Boettger colln.); SMF 216143 (1 sh, pre-1970, ex S.H.F. Jaeckel colln., ex Feldmann colln.); SMF 297043 (1 sh, pre 1937, ex H.F.P. Ehrmann colln., ex W. Schlüter colln.); SMF (297044 (1 sh, G. Maegele colln.); SMF 297045 (2 sh, pre-1929, ex W. Schlüter colln., ex F.H. Rolle colln.); SMF 297046 (2 sh, pre-1929, ex F.H. Rolle colln.); SMF 297047 (2 sh, pre-1937, ex H.R.G. Kaltenbach colln.); SMF 297048 (1 sh, pre-1963, ex H.R.G. Kaltenbach colln.); SNSD 10578 (1 sh, pre-1895, ex Piper colln.); SNSD 32859 (4 sh, col. Bomeier 1939, ex Regius colln.); SNSD 56391 (1 sh, ex Theodor & Paul Reibisch colln.); USNM 21057 (1 sh); USNM 57280 (3 sh, ex Stearns colln.); USNM 106423 (1 sh, ex Lea colln.); USNM 217252 (3 sh, ex Henderson colln.); USNM 307601 (1 spm, ex Henderson colln.); USNM 307626 (1 sh, ex Henderson colln.); USNM 316168 (1 sh, ex Evezard colln.); ZMA.MOLL.397226 (1 sh, ex R.J. van Lennep colln.); ZMA.MOLL.397227 (1 sh). Pará (?) state: AMNH 119005 (1 sh, pre-1964, ex Julius Wisoff colln.). Bahia state: AMNH 43887 (2 sh, pre-1868, ex W.A. Haines colln.); ANSP 400548 (1 sh, col. "farm worker" iii/1983, Salvador municipality, on ground in forest, ex D. Naide & J. Naide colln.); ANSP 426504 (1 sh, viii/1993, N Itabuna municipality [Guadu], under dead leaves in tropical forest, ex I. Wistar Morris III colln.); ANSP 448465 (1 sh, iv/1993, NNE Ilhéus municipality, under dead leaves, ex I. Wistar Morris III colln.); FMNH 193212 (1 sh, Una forest [likely Una Biological Reserve], col. R. Harley & B. Verdcourt 29/i/1977); NHMUK unnumbered (2 sh, col. G.P. Lewis & B. Verdcourt 2/xii/1981, Una municipality, 30-35 km S of Olivença, Ilhéus-Una road, restinga forest by roadside, ca. 40 m a.s.l. [likely Una Biological Reserve]); MNCN 15.05/39938 (3 sh, col. Azpeitia); MZSP 1640 (3 sh); MZSP 34823 (2 spm, Pimenteira municipality); MZSP 38809 (1sh, Ilhéus municipality, col. B. Jahyny); MZSP 47683 (2 sh, eastern Bahia, ex M. Roxo colln.); MZSP 47695 (4 sh, eastern Bahia, ex M. Roxo colln.); MZSP 62060 (1 spm, Serra Grande municipality, Praia do Pé da Serra, col. M.C. Guerrazzi 29/x/2004); MZSP 62061 (1 spm, Uruçuca municipality, Estância Fonte das Águas, col. M.C. Guerrazzi 10/xi/2004); MZSP 66950 (2 sh, Ilhéus municipality, col. A. Bodart x/2001); MZSP 72058 (1 sh, Itacaré municipality, col. P. Conçalves x/2005); MZSP 73581 (1 sh, Ilhéus municipality, col. A. Bodart x/2001); MZSP 81075 (1 sh, col. L.R.L. Simone 1972); MZSP 96518 (1 sh, Ilhéus municipality, col. J.H.C. Delabie); MZSP 98742 (1 spm, Canavieiras municipality, 15°20'34"S, 39°01'00"W, col. J.R.M. Santos 13/v/2010); MZSP 116519 (1 sh, Itaparica municipality, col. A. Wallerstein xi/1973, ex J. Vaz colln.); MZSP 129318 (9 sh, Pimenteira municipality, col. A. Bianchi vi/2012); NHMD 615854 (2 sh, 1863, ex Andrea colln.); NHMW-MO-unnumbered (8 sh, Cachoeira [Cachoeirinha] - Una, F. Adolpho col.); NHMW-MO-unnumbered (2 sh, pre-1960, Cachoeira [Cachoeirinha] - Una, ex. Edlauer colln.); NHMW-MO-unnumbered (6 sh, pre-1980, Cachoeira [Cachoeirinha] - Una, ex Klemm colln.); NMR 12118 (1 sh); SMF 216144 (1 sh, “Santos” [likely Todos-os-Santos Bay], pre-1970, ex S.H.F. Jaeckel colln.); SMF 316773 (1 sh, pre-1896, ex Z.I. Heidelberg colln. 1897Moll.1443); USNM 307595 (3 sh, ex Henderson colln., ex Redfield colln.); USNM 1202125 (3 sh, NE Ilhéus, under dead leaves, col. A. Bianchi x/2001).

Online records.

iNaturalist: BRAZIL. Bahia state: id 13527047 ( São Sebastião do Passé municipality, lat -12.44740646 long -38.41546864, obs. Ben Phalan “deboas” 17/vi/2018 13:25:06 UTC); id 14349827 and id 14349831 ( São Sebastião do Passé municipality, lat -12.45972252 long -38.40000153, obs. “sidnei-sampaio” 14/vii/2018 13:56:40 UTC). Other websites: BRAZIL. Bahia state: Allspira ( Valença municipality, under dead leaves, 2006; http://allspira.com); Conchology ( Ilhéus municipality, under dead leaves in tropical rain forest; https://www.conchology.be); Forum Francophone des Coquillages Actuels (Pimenteira municipality, under dead leaves in tropical forest, vi/2012; http://www.forumcoquillages.com/)

Remarks.

Even though Born (1778, 1780) noted the provenance of his specimen (Fig. 1A ) as unknown ("patria ignota"), it was almost certainly collected in Brazil. Schileyko (2006), in fact, gave Brazil ( “Brasilia”) as the locality for Born’s holotype. Given that the only confirmed locality in Brazil is Bahia state (which was a usual stop for shell collectors in the late 18th century), Born’s specimen, in all likelihood, stems from there.

One of the localities of occurrence indicated by Simone (2006), the municipality of Central, is mistaken. It was based on the work of Lima and Oliveira (1992), who reported P. polygyrata from an archaeological setting in that municipality. Their identification is erroneous and their specimen ( Lima and Oliveira 1992: fig. 4) actually belongs to Systrophia (Entodina) Ancey, 1887, given the shell size and parietal fold in the aperture.

The only locality indicated by a specimen outside Bahia state is Pará state, in northern Brazil (predominantly an Amazon Forest region), found on a specimen from a private shell collector ( AMNH 119005; Fig. 1C ). This specimen, despite having a slightly smaller size than average and a wider aperture, is overall indistinguishable from specimens from Bahia. Thus, this locality must be considered likely erroneous, as no other specimen from a trustworthy source is known from there.

Polygyratia charybdis was described by Mörch (1852) and has alternatively been considered in literature as a full species, a subspecies or a synonym of P. polygarata . Mörch’s types are partially housed in the NHMUK and the NHMD ( Dance 1966) and we could trace a possible holotype in the collection of the latter (NHMD 615842, Fig. 1F ). The work of Mörch (1852) served as a catalogue of the collection of the Count of Yoldi for an auction. The possible holotype bears the typical label of Yoldi’s collection (Tom Schiøtte, pers. comm.), including the species number in the catalogue (145). Furthermore, Mörch (1852) reported that his specimen measured 38 mm, which is perfectly in line with the specimen. As such, there is a good likelihood that this specimen is the holotype; however, it is not in pristine condition (Fig. 1F ).

The original description ( Mörch 1852), as well as later works that repeated it, listed very unspecific diagnostic characters: a more flat and concave shell, broader whorls, a narrower and deeper umbilicus and a smaller diameter (38 mm). The type locality is simply “Brazil” and there is no indication of other places ( Mörch 1852). Albers (1860) indicated Bolivia as a second locality of occurrence; whether this was a misunderstanding on his part or an error based on specimens he misidentified, remains unknown. In any event, the erroneous locality “Bolivia” has been consistently reproduced in literature ever since (e.g. Simone 2006). Even so, there are no known specimens from that country and this locality must be considered erroneously listed.

The possible holotype (Fig. 1F ) and a few other specimens (e.g. AMNH 119005, Fig. 1C ) are indeed smaller and present features that could be interpreted as diagnostic of P. charybdis , such as a deeper umbilicus. Nevertheless, when all the specimens are taken together (Fig. 1 ), it is clear that these “diagnostic” features are just artefacts of morphological constraints due to the specimens being slightly smaller than the species’ mean diameter. That is, by reaching adulthood with a smaller size (and consequently fewer whorls), some specimens inevitably end up displaying a narrower and deeper umbilicus. Here, we consider this is simple morphological variability of the species and treat P. charybdis as a synonym of P. polygyrata .

Figures

Figure 1. Shells of Polygyratia polygyrata, showing the variation in conchological characters such as size, number of whorls and aperture shape, as well as colouration. Scale bar = 2 cm. A. Holotype, NHMW-MO- 14371 (NHMW). B. AMNH 43887 (AMNH). C. AMNH 119005 (AMNH). D. SMF 26248 (SMF). E. Example of a weathered specimen, which acquires a washed-off ochre / brown colouration, MNZ M. 233517 (MNZ). F. Possible holotype of Polygyratia charybdis, NHMD 615842 (NHMD).

Figure 2. Internal lamellae in the shell of Polygyratia polygyrata. A. Broken specimen showing the second set of internal lamellae, FMNH 40632 (FMNH). B-F. CT scan image showing the internal structures of an intact shell (MZSP 129318). B. Whole shell showing the two sets of internal lamellae. C, D. First set of internal lamellae. E, F. Second set of internal lamellae. Scale bar: 2 cm (A, B).

Figure 3. Map of Bahia state showing the known distribution of Polygyratia polygyrata. Squares: museum specimens. Circles: online records. Triangle: literature data.