Monthly Archives: December 2013

The status of Sparnotion Pilsbry, 1944

In 1872, Hippolyte C. Crosse published a brief paper with diagnoses of new molluscs, one of which was Bulimus hauxwelli (Crosse, 1872: 211). This species was named after John Hauxwell, who collected mainly birds, mammals and fishes during trips in Peru and Ecuador (Bartlett 1882; Böhlke 1984). Hauxwell collected this malacological material near the Ambiyacu river, at Pebas, Dept. Loreto, eastern Peru and donated it to James Orton, whose collection at that time was kept in Vassar College, Poughkeepsie, NY.
Crosse (1872: 211), who did not state on how many specimens his description was based, referred to “Col. Orton”. He further remarked “Species insignis, ad sectionem Pelecychilorum Guildingi pertinens, inter Bulimum goniostomum Ferussaci et B. distortum Bruguierei quasi media”; this may be liberally translated in ‘A remarkable species belonging to Pelecychilus Guilding, halfway between Bulimus goniostomus Férussac [Gonyostomus gioniostomus, Strophocheilidae, eastern Brazil (Simone 2006: 203)] and B. distortus Bruguière [Plekocheilus (Eudolichotis) distortus, Amphibulimidae, northern South America (Borrero & Breure 2011: 50-51, fig. 14E)]’. During the next year Crosse published a French translation and a figure of this species (Crosse 1873: 252-253, pl. 11 fig. 2). He said it was communicated via Thomas Bland, correspondent for the Journal de Conchyliologie in New York.

Pilsbry (1896 [1895-1896]: 120-121, pl. 44 figs 75-78) re-described and re-figured this taxon “through the courtesy of Prof. William B. Dwight, of Vassar College” on the basis of “the type and another specimen preserved in the museum of that college”. One of these specimens is now in the collection of the Museum of Comparative Zoology at Harvard, Cambridge, MA (MCZ 202073). Turner (1962) explained that in 1874 the type material, returned to Orton after the description by Crosse, has been transferred to the MCZ collection. Unfortunately, after Pilsbry used the holotype for his re-description, it “has since been misplaced or lost”; the MCZ specimen is thus a paratype. Pilsbry classified the species with his subgenus Plekocheilus (Eudolichotis) Pilsbry, 1896 and singled P. (E.) hauxwelli out in the key for the subgenus (Pilsbry 1896 [1895–1896]: 109), distinguishing it from P. (E.) distortus (Bruguière, 1789) and P. (E.) aurissciuri (Guppy, 1866) by having (1) a “minutely, densely but irregularly scattered, papillose” sculpture on the last whorl; (2) “longitudinal groups of crowded, finely zigzag hydrophanous lines” on the dorsal side of the last whorl (Pilsbry 1896 [1895-1896]: pl. 44 fig. 78); (3) a narrow, “not calloused” lip. Many years later, Pilsbry (1944) referred to this characteristics presented in this key to define his new subgenus Plekocheilus (Sparnotion), with its sole species P. (S.) hauxwelli. This subgenus has been recognised by Zilch (1960 [1959-1960]: 476, fig. 1674), and Breure (1979: 32); Schileyko (1999: 277: fig. 334) expressed some doubt about its status by placing a question mark, but did not explicitly comment on this in his text.

The loss of the holotype of Bulimus hauxwelli makes it necessary to judge this taxon—and the subgenus Spanotion—largely on the basis of the figures provided by Pilsbry and the remaining paratype in MCZ. As far as I know there is no material with proven locality data present in museum collections. Recently, I had the opportunity to re-study the specimen in MCZ on the basis of hi-res pictures supplied by Adam Baldinger. As noted earlier (Breure 1978: 22), the paratype does not show the “longitudinal groups of crowded, finely zigzag hydrophanous lines” very clearly and this could hardly be compared to the subcuticular cavities filled with air characteristic for Plekocheilus (Aeropictus); see also Borrero & Breure 2011: fig. 6 for shell sculptures of several Plekocheilus species. While the paratype shell shows a papillose sculpture of the last whorl (unfortunately not clearly shown on the picture), I think this sculpture is not atypical compared to the known species of Plekocheilus (Eudolichotis). The sprout in the basal lip seems stronger than in Crosse’s or Pilsbry’s figures; this may be a sign for intra-specific variation. Finally, the narrow and ‘not calloused’ lip reminds me of several Plekocheilus (Eurytus) species and I hardly doubt if this characteristic alone may be sufficient for a subgeneric separation of this species.
Based on the shell morphology alone I conclude that this species may be best classified as P. (Eudolichotis) hauxwelli untill more material, hopefully allowing for anatomical and molecular studies, becomes available.

References

Bartlett, E. (1882). On some mammals and birds collected by Mr. J. Hauxwell in Eastern Peru. — Proceedings of the Zoological Society of London 1882: 373–375.
Böhlke, E.B. (1984). Catalog of type specimens in the ichthyological collection of the Academy of Natural Sciences of Philadelphia. — Special Publication Academy of Natural Sciences of Philadelphia 14: i–viii, 1–246.
Borrero, F.J. & Breure, A.S.H. (2011). The Amphibulimidae (Mollusca: Gastropoda: Orthalicoidea) from Colombia and adjacent areas — Zootaxa 3054: 1–59.
Breure, A.S.H. (1978). Notes on and descriptions of Bulimulidae (Mollusca, Gastropoda). — Zoologische Verhandelingen 164: 1–255.
Breure, A.S.H. (1979). Systematics, phylogeny and zoogeography of Bulimuinae (Mollusca). — Zoologische Verhandelingen 168: 1–215. Crosse, H.C. (1872). Diagnoses molluscorum novorum. — Journal de conchyliologie 20: 211–214.
Crosse, H.C. (1873). Description d’espèces nouvelles. — Journal de conchyliologie 20: 248–254.
Pilsbry, H.A. (1895–1896). American bulimi and bulimuli. Strophocheilus, Plekocheilus, Auris, Bulimulus.Manual of Conchology (2) 10: 1–213.
Pilsbry, H.A. (1944). Peruvian land Mollusca, III. — The Nautilus 58: 28–30.
Schileyko, A.A. (1999). Treatise on Recent terrestrial pulmonate molluscs, 3. Partulidae, Aillyidae, Bulimulidae, Orthalicidae, Megaspiridae, Urocoptidae. — Ruthenica, Supplement 2: 263–436.
Simone, L.R.L. (2006). Land and freshwater molluscs of Brazil: 1–390. EGB/Fapesp, Sao Paulo.
Turner, R. D. (1962). James H. Orton – his contribution to the field of fossil and Recent mollusks. — Revista del Museo Argentino de Ciencias Naturales “Bernardino Rivadvia” (Ciencias Zoológicas) 8(7): 86–99.
Zilch,  A. (1959–1960). Gastropoda, Euthyneura. In W.  Wenz, Gastropoda. Handbuch Paläozoologie 6, 2: 1–835. Borntraeger, Berlin.

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Microscopy and morphology

In a recent paper, Medeiros et al. (2013) gave a detailed account of the reproductive system morphology of the wide-spread species Leptinaria unilamellata through histological studies. The results are described at length and with ample microscopic photos.

Many tropical terrestrial gastropods, such as Subulinidae, are recognized and classified by their shells, as is the case for Leptinaria unilamellata (d’Orbigny, 1835), a hermaphroditic pulmonate snail restricted to tropical America. We aimed to characterize the morpho-anatomy and histology of the reproductive system of L. unilamellata. We compared the results obtained from L. unilamellata with the available data on the reproductive system of other subulinid species. The main distinctive characters are those of the penial complex, such as the proportion of the length of the penial complex and the length of the free oviduct, presence of a flagellum, site of insertion of the bursa copulatrix duct relative to the site of insertion of the penial complex and presence and extension of the penial sheath.

In the discussion, reference is being made to “A. fulica and A. monochromatica” (p. 2401); given the context it is not clear that the authors likely meant species classified within the genus Achatina.

Reference:
Medeiros, C., Daniel, P. A., Santos, E. O., Ferreira, P. B., Caldeira, R. L., Mendonça, C.L.F., Carvalho, O. S. & D’ávila, S. (2013): Macro- and microscopic morphology of
the reproductive system of Leptinaria unilamellata (d’Orbigny, 1835) (Mollusca: Pulmonata: Subulinidae) — Journal of Natural History 47: 2385–2407.

Oxychilus in Chile

While the European species Oxychilus alliarius (Miller, 1822) has been mentioned here as an invasive species in Chile, Cádiz et al. has just published a study which confirms this on morphological and molecular grounds.

In the present study we report the first record of the western European terrestrial snail Oxychilus alliarius (Miller, 1822) for continental Chile. Oxychilus alliarius is known for its highly predatory and invasive behavior, being directly associated with the decline of native snail populations in places where it has been introduced. Continental Chile has, on the other hand, the highest generic and specific endemism known for Punctoidea in the American continent, most of them potential prey for O. alliarius. The different species of Oxychilus are easily misidentified because of their conchological similarity. To overcome misidentification, we analyzed both morphological and molecular data which should enable the unambiguous identification of O. alliarius. In order to engage and facilitate further studies we describe and illustrate characters of the radula, shell, and present molecular data of O. alliarius, which are useful and necessary for distinguishing O. alliarius from its sister species.

Reference:
Cádiz, F.J., Cádiz, D.G. & Grau, J.H. (2013). An invasive predatory snail Oxychilus alliarius (Miller, 1822) (Stylommatophora: Zonitidae) threatens the native malacofauna of continental Chile: a morphological and molecular confirmation. — Studies on Neotropical Fauna and Environment 48: 119–124.

What you can see in a snail

Moving on my (slimy) side-track of trying to identify land snails on paintings and other works of visual arts, I found something interesting related to European snails. By the end of the Middle Ages religious motifs were still very much ‘en vogue‘ in visual arts. Italian painters were especially good at this theme, and one of them was Francesco del Cossa (c. 1430/1435 – 1477). He worked in Ferrara in northern Italy and made c. 1470/1472 the work ‘Annuncio’, which is now in the Staatliche Kunstsammlungen in Dresden.

You see in the foreground a snail on the move to the right; you can’t deny, it’s so obvious. Catching the eye… But to my knowledge this is the first painting where a snail is pictured in such great detail if you zoom into it. Art historians have attached different symbolic meanings to snails; in the case of this painting the iconographic snail would exemplifying “the perpetual virginity of Mary” (Ettlinger, 1978). But I also found a different, well-written opinion in a book by the French art historian Aresse (see Waters, 2008), who believes the snail “makes you understand that you are seeing nothing in what you are looking at”. Food for art historians…

Anyway, what species are we seeing here? According to Aresse this is “a good old Burgundy snail” [i.e. Helix pomatia]. But I don’t think it is what Aresse thought he was seeing. Why would a painter in northern Italy use a French species he might even not have known? Would it be not more plausible to use a species that could be locally obtained? If so, we need to look at the Italian malacofauna. In Cesari (1978) I found a shell very similar to the one in Cossa’s work; pl. 5 fig. 1 shows Helix cincta Müller, 1774 from the same area where Cossa worked. The same broad pale band along the suture and a small one on the periphery. That is what I see in this snail.

Later in time we see that more painters started to use these ‘domestic commodities’. But that’s quite another story…

References:
Cesari, P. (1978). La malacofauna del territorio Italiano (Note di aggiornamento e diffusione conoscitiva), 1o contributo: il genere Helix. — Conchiglie (Milano) 14: 35–90.
Ettlinger, H.S. (1978). The virgin snail. — Journal of the Warburg and Courtauld Institutes 41: 316.
Waters, A. (2008). The snail’s gaze. Available at http://intranslation.brooklynrail.org/french/the-snail’s-gaze.

Photo of the day (149): Plekocheilus

Philippe Kok very kindly shared some additional photographs of living Plekocheilus snails from tepuis in Venezuelan Guayana.

The first picture was taken at night on Auyán-tepui in the Chimantá massif. It is a very yellow coloured specimen of P. (Eurytus) mundiperditi Haas, 1955. This species is well known from this area and may be found on several of the tepuis in this massif.

The second snail was found on Uei-tepui, also known as Cerro El Sol, an isolated mountain-top south-east of Roraima. This tepui was hitherto malacologically terra incognita, but the photo is interesting in several aspects. First, this appears to be P. (E.) sophiae Breure, 2009, which was until now only known from Yuruani-tepui, NW of Roraima. Secondly, this shell has had a severe ‘life accident’ as shown by the upper part of the last whorl near the peristome; looks like a repaired shell after a predator attack (mammal??). Finally, the colour pattern at the penultimate whorl is peculiar (lighter and darker spiral bands), but has been observed in other species as well; this may be due to either a genetic defect regulating the colour pattern genes or may have been induced by another damage of the shell (on the side not shown here).

More information on this group may be found via this link: http://bit.ly/IOYgok

Plekocheilus mundiperditi Plekocheilus sophiae

Mirinaba cadeadensis in southern Brazil

In the online journal CheckList a paper just has been published on a rare strophocheilid species, Mirinaba cadeaqdensis (Morretes, 1952). The paper by Birckolz et al. gives data on 11 new localities where this species has been found, of which one specimen alive. The species has been found from 30–700 m altitude in protected patches of Atlantic Rainforest. As the authors note, the conservation of this species would require further data on the morphological variation, distribution and ecology. May I suggest also anatomical and molecular data?

The paper can be found here: http://www.checklist.org.br/getpdf?NGD108-13

Reference:
Birckolz, C.J., Gernet, M. de Vasconcellos & Serbana, A.L. (2013). Range extension of Mirinaba cadeadensis (Morretes, 1952) (Gastropoda: Pulmonata: Strophocheilidae) along the coast of Paraná, southern Brazil. — CheckList 9 (6): 1561–1563.