Monthly Archives: November 2014

Population structure Megalobulimus

Miranda et al. (2015) published (advanced online) a paper dealing with two Megalobulimus species. Their abstract reads as follows: “Native Megalobulimus paranaguensis was identified on Brazil’s Ilha Porchat promontory, an area that Achatina fulica commonly populates. The population structures of these species were investigated for interactions. Spatial distribution, niche overlap and mark–recapture analysis were conducted. The outer lip of M. paranaguensis and environmental variables were measured.

Miranda f3

Miranda f2

One and two abundance peaks were observed for A. fulica and M. paranaguensis, respectively. Survivorship was higher in A. fulica. Distribution was aggregate for M. paranaguensis, whereas for A. fulica it varied from random to aggregate. Both species aggregate as abundance increases. The lifespan of M. paranaguensis in this location is shorter than its lifespan in a nearby location. Achatina fulica was affected by soil temperature and humidity; M. paranaguensis was influenced by humidity. Niche overlap was random. The results show that M. paranaguensis can keep its
natural activity and abundance in the presence of A. fulica, but environmental degradation impacts M. paranaguensis and should be evaluated.”

As can be seen from the above figures, the observations were made during one year resp. 7 months. The conclusions thus have to be viewed within the context of this limited evidence.

References:
Miranda, M.S., Fontenelle, J.H. & Pecora, I.L. (2014 [2015]). Population structure of a native and an alien species of snail in an urban area of the Atlantic Rainforest. – Journal of Natural History, 49: 19-35.

Reviews of Annulariidae

G. Thomas Watters recently had two papers out on Annulariidae. The first one (2014a) is a “preliminary review” of the Lesser Antillean species. The brief abstract reads “The Annulariidae of the Lesser Antilles, including the Virgin Islands, Isla de Vieques, and Isla Culebra, are reviewed. Eleven species are recognized in three genera. With rare exceptions, all occur in the Limestone Caribbees. One species, Parachondria basicarinatus (Pfeiffer, 1855), from St. Croix, may be extinct. All are believed to be related to Puerto Rican taxa.”

The following species are recognised: Chondropoma (Chondropoma) julieni Pfeiffer, 1866; Chondropoma (Chondropoma) pupiforme (Sowerby, 1843); Chondropoma (Chondropoma) rufilabre (Potiez & Michaud, 1838); Parachondria (Parachondria) basicarinatus (Pfeiffer, 1855); Parachondria (Parachondria) lineolatus (Lamarck, 1822); Parachondria (Parachondria) santacruzensis (Pfeiffer, 1855); Diplopoma (Diplopoma) crenulatum (Potiez & Michaud, 1838); Diplopoma (Diplopoma) decussatum (Lamarck, 1822); Diplopoma (Diplopoma) sulculosum (Pfeiffer, 1852).

Watter2014a

The second paper (2014b) presents a revision of the Central American taxa of the family. “Twenty annulariid taxa are reviewed from Central America, including three new species and one new genus. One species is regarded as an incertae sedis and two as mislabeled lots of Cuban origin. Many species are highly endemic. Although not speciose, Central America has a high diversity of conchological forms and may represent the ancestral source of annulariids
in general.” A key to the genera is also presented.

The following taxa are recognised c.q. described: Choanopomops largillierti (Pfeiffer, 1846); Halotudora gaigei (Bequaert & Clench, 1931); Halotudora gruneri (Pfeiffer, 1846); Halotudora kuesteri (Pfeiffer, 1852); Gouldipoma chiapasense (Crosse & Fischer, 1877); Gouldipoma sumichrasti (Crosse & Fischer, 1874); Gouldipoma coltrorum new species; Gouldipoma terecostatum (Thompson, 1966); Gouldipoma callipeplum (Solem, 1961); Gouldipoma chrysostiria new species; Gouldipoma thomasi (Solem, 1961); Gouldipoma trochleare (Pfeiffer, 1852); Tudorisca andrewsae (Ancey, 1886); Paradoxipoma new genus; Paradoxipoma enigmaticum new species; Diplopoma osberti (Tristram, 1861); Diplopoma rigidulum (Morelet, 1851); Parachondria cordovanus (Pfeiffer, 1857); Parachondria cordovanus (Pfeiffer, 1857); “Choanopoma” cygni Pilsbry, 1930.

Watters2014b

For all of these taxa data are given about type material, synonymy, material seen and distribution, habitat and conservation status, (re-)description, variation, comparison with other taxa, original description (translated), etymology.

These two very thorough papers are new hallmarks for this group of snails.

References:

Watters, G.T., 2014a. A preliminary review of the Annalariidae (Gastropoda: Littorinoidea) of the Lesser Antilles. – The Nautilus 128: 65–90.
Watters, G.T., 2014b. A revision of the Annulariidae of Central America (Gastropoda: Littorinoidea). – Zootaxa 3878: 301–350.

 

Giant Euglandina’s

Fred Thompson recently published a brief paper on the relatively poorly known malacofauna of Honduras. Two giant Euglandia species were noticed from among material collected by the author in 1993–1995. Giant species of this genus are “seldom found, judging ny the few specimens that have made their way into malacological collections and on the basis of my field experiences”. Both novelties are described from a restricted and difficult accessible area.

Euglandia (E.) hyperion is described from four specimens; holotype UF 476155 from Honduras, Dept. Sanata Barbara, San Luis de Planes. E. (E.) encladus (holotype UF 468668) originates from the same area, NW of San Jose de los Andes.

Screen Shot 2014-11-17 at 20.11.43

Reference:
Thompson, F.G., 2014. Two new carnivorous land snails of the genus Euglandina (Gastropoda: Pulmonata: Spiraxidae) from Honduras. – The Nautilus 128: 97–100.

 

Spotted…

The new Naturalis 2.0?

2014-11-18 13.01.14

I noticed a few grey blobs seemingly snails in front of the building, which should warrant showing this picture, but also a large sign on the side.

2014-11-18 13.01.14 copy2

If Edwin was a Man, he would be bring our Mosasaurus (now in Paris) back, not a North American endemic…

 

Santa Catarina new records

Agudo et al. (2014) published nine new records for the fauna of the State Santa Catarina in Brazil.

The following taxa are concerned:
Family Helicinidae
Helicina schereri F. Baker, 1913
Family Assimineidae
Assiminea sp.
Family Subulinidae
Lamellaxis clavulinus (Potiez & Michaud, 1838)
Lamellaxis (Leptopeas) cf. mizius Marcus & Marcus, 1968
Family Bulimulidae [Amphibulimidae]
Plekocheilus (Eurytus) sp. [the specimen shown is mentioned as P. aff. rhodocheilus (Reeve, 1849) in my previous post]
Rhinus cf. longisetus (Moricand, 1846)
Family Amphibulimidae [both Rhinus and Simpulopsis are now placed in the Simpulopsidae sensu Breure & Romero, 2012]
Simpulopsis cf. ovata (Sowerby, 1822)
Family Megalobulimidae
Megalobulimus klappenbachi Leme, 1964
Family Charopidae
Zilchogyra cleliae Weyrauch, 1965

Agudo ea 2014f7

Reference:
AGUDO-PADRÓN, A.I.; LUZ, J.S.; FUNEZ, L.A.; ZERMIANI, A.E., 2014. Nine new records to inventory of continental mollusc species from Santa Catarina State, Central Southern Brazil. Brazilian Journal of Biology Sciences, 1(1): 15-20. Available at: http://revista.rebibio.net/v1n1/3543-4376-01-03.html

The sound of a snail

Some time ago I posted a note on a mysterious snail found in southern Brazil, supposedly Plekocheilus aff. rhodocheilus (Reeve, 1849) (here). ‘The snail has gotten a tail’, so to speak, as the original audio fragment has been analysed and another case of sound production in land snails turned up, shedding light on this seemingly forgotten topic.

Breure2014f2

Many thanks are due to Germano Woehl jr. for sharing the original audio file.

Link: http://mollus.oxfordjournals.org/cgi/reprint/eyu079? ijkey=bXqfr0IbP5ro78U&keytype=ref 

It would be interesting to further investigate e.g. the relationships between size of the species and sound to be made.

Diversity of Helicinidae

Although already presented at the “Magnitude of molluscan diversity – the known and the unknown” Symposium held at the 78th meeting of the American Malacological
Society (2012), Ira Richling’s excellent paper on diversity of the Helicinidae was recently published (Richling, 2014).

Richling2014f2

Presenting a history of helicinid research starting in 1801 (the first taxon described was a Jamaican species), she has analysed the development of the diversity through time and also a number of revisions to compare the number of accepted (sub)species to available names. Under ‘Drawbacks in exploration’ several aspects (listed below in the abstract) are extensively discussed, which have an importance beyond the scope of the paper.

It would be interesting to explore these issues for other (large) land snail families in the (Neo)tropics. One of these issues is the “limited availability of wet preserved material”, which is quite crucial to make advances both in morphological and molecular studies. Unfortunately, the forthcoming implementation of the Nagoya Protocol (cf. Renner et al., 2012) makes things probably worse and opens up the possibilities for unwarranted claims from local scientists and license authorithies for financial expenditures, and more (examples are known of claimed co-authorship for several papers without any content contribution). Given the ongoing crisis in natural history museums, this is an avenue leading to disasters.

Richling2014f4

The full abstract of the paper reads: “Helicinids represent a family of tropical land snails with a distribution range limited to the subtropical and tropical zones of the New World, Australasia, and the Pacific. For an estimate of diversity in this poorly systematically revised group, the total number of described taxa was determined and used for calculations based on analyses of selected case studies with regard to the percentage of valid and new taxa.
Extensive bibliographic searches identified about 1,250 available names, regardless of rank, that were described from 1801 onward. Fiftyeight percent of the names represent New World taxa whose majority (63%) was created before 1880 while the intensive study in most of the
Australasian and Pacific areas started much later with the bulk of taxa described between 1880–1930. An analysis of the distribution of the type localities and the times of descriptions allowed for identification of scarcely- and well-studied areas.
Eight potentially representative case studies of major revisions were compared with respect to changes in described versus “true” diversity. The geographic range covered Costa Rica, Cuba, Jamaica, Lesser Antilles, New Caledonia, northeast Australia, and the Hawaiian and Gambier
Islands. In these studies approximately half of the available names were regarded as synonyms (range from 37 to 72%). On the other hand, 36 to 41% of the recognized diversity represented new species depending on whether a more lumping or splitting approach was considered, the
latter simulated by simply counting subspecies as equal units of diversity. The amount of new taxa ranged from 2% (Cuba) to 90% (Gambier Islands). Under the assumption that six of the studies were representative throughout the area of distribution, worldwide diversity would
range from 770 to 1,140 species or up to 1,400 species if the studies from the Australasian-Pacifi c area were realistic. Although obviously poorly studied, in comparison with an estimate for all continental molluscs of Mexico and Central America by Thompson (2011), helicinids
would still be among the better documented snail families for this region.
The following aspects and their consequences are discussed as most significant drawbacks in the exploration of helicinids: questionable systematic concepts above species level; limited recognized differentiating characters and convergence; species complexes and last, massive
habitat loss, increasingly fragmented distribution and extinction. Another practical aspect is the rather limited availability of wet preserved material”.

References:
Renner, S.C. et al., 2012. Import and export of biological samples from tropical countries—considerations and guidelines for research teams. – Organisms, Diversity & Evolution 12: 81–98.
Richling, I., 2014. Poorly explored jewels of the tropics: Estimating diversity in non-pulmonate land snails of the family Helicinidae (Gastropoda: Neritopsina). – American Malacological Bulletin 32: 246–258.