Tag Archives: argentina

Clessinia from Argentina

A recent paper by Cuezzo et al. provides a revision of Argentinian species. Their abstract reads in full:

“Background: Land gastropods of the Dry Chaco merit special attention because they comprise a highly diverse but barely studied group. Clessinia Doering, 1875 are typical inhabitants of this ecoregion. The inclusion of their distribution areas into Spixia range, their shell shape similarities, and a former molecular study raised doubts on the monophyly of this genus. The present study review the species of Clessinia, under a morphological, geometric morphometrics, and molecular combined approach.
Methods: Adults were collected, photographed, measured, and dissected for anatomical studies. Shell ultrastructure was studied with scanning electron microscope. Geometric morphometric analyses on shells were performed testing if they gave complementary information to anatomy. Two mitochondrial genes, and a nuclear region were studied. Phylogenetic reconstructions to explore the relationships of DNA sequences here obtained to those of Clessinia and Spixia species from GenBank were performed.
Results: Species description on shell, periostracal ornamentation and anatomy is provided. We raised former Clessinia cordovana striata to species rank, naming it as Clessinia tulumbensis sp. nov. The periostracum, consisting of hairs and lamellae, has taxonomic importance for species identification. Shell morphometric analyses, inner sculpture of penis and proportion of the epiphallus and penis, were useful tools to species identification. Nuclear markers do not exhibit enough genetic variation to determine species relationships. Based on the mitochondrial markers, genetic distances among Clessinia species were greater than 10%, and while C. cordovana, C. nattkemperi, and C. pagoda were recognized as distinct evolutionary genetic species, the distinction between C. stelzneri and C. tulumbensis sp. nov. was not evident. Clessinia and Spixia were paraphyletic in the molecular phylogenetic analyses. Species of Clessinia here treated have narrow distributional areas and are endemic to the Chaco Serrano subecoregion, restricted to small patches within the Dry Chaco. Clessinia and Spixia are synonymous, and the valid name of the taxon should be Clessinia Doering, 1875 which has priority over Spixia Pilsbry & Vanatta, 1894.
Discussion: Our results support the composition of C. cordovana complex by three species, C. cordovana, C. stelzneri, and C. tulumbensis sp. nov. The low genetic divergence between C. stelzneri and C. tulumbensis sp. nov. suggests that they have evolved relatively recently. The former Spixia and Clessinia are externally distinguished because Clessinia has a detached aperture from the body whorl forming a cornet, periostracal microsculpture extended over dorsal portion of the peristome, five inner teeth on the shell aperture instead of three–four found in Spixia. Morphological similarities exists between both genera in shell shape, type of periostracum microsculpture, reproductive anatomy, besides the overlap in geographic ranges”.

Schermafbeelding 2018-12-15 om 15.59.37

This is an interesting paper for me, as more than 6 years ago I did research on type material in the London museum and found the species of the two ‘genera’ difficult to entangle, the more when phylogenetic results proved a paraphyletic relationship (Breure & Romero, 2012). This study comes to the same phylogenetic outcome as shown in the figure below. And for clarity: the Clessinia specimens used in our 2012 study were identified and supplied to us by one of the current authors and another Argentinian malacologist; they had more expertise and resources available.

Schermafbeelding 2018-12-15 om 15.53.44

The conclusion of the study by Cuezzo et al. is that Clessinia and Spixia are synonyms, with the older name (Clessinia) taking precedence. As such this is correct, but at the same time they conclude that the two ‘genera’ are morphological distinguishable (see the Discussion in their abstract). As taxonomists we have a solution for this: the subgenus…, which is treated in MolluscaBase as ‘alternate representation’. So instead of complete synonymisation, I would say there seems enough reason to distinguish the two as subgenera despite not being strictly monophyletic. The nomenclature then becomes:

Clessinia Doering, 1875
Clessinia (Clessinia) Doering, 1875 – type species Bulimus (Clessinia) stelzneri Doering, 1875.
Clessinia (Spixia) Pilsbry & Vanatta, 1898 – type species Clausilia striata Spix in Wagner, 1827.
See Cowie et al. (2004) for details on the names of Spix and Wagner.

Screenshot 2018-12-11 at 05.30.48

In this paper also one new species is described. The authors say “The new species, Clessinia tulumbensis sp. nov. include Clessinia cordovana striata (Parodiz, 1939). The name striata has not been used here to avoid homonymy with Pupa striata Spix, 1827 [= Clausilia striata Spix in Wagner, 1827], the type species of Spixia, since in the present study the genera Clessinia and Spixia are proposed as synonymous. The new species with its own holotype and paratypes is defined based on live-collected material from which DNA sequences were obtained and the anatomy described. In this sense, although the Parodiz name is preoccupied, we are not replacing the name proposed by him in 1939 but creating a new species with its own type series”.

With Parodiz’ name mentioned by the authors as a full synonym, I fail to see the reason to introduce the name tulumbensis as a species novum. Although it is correct to replace the name of Parodiz to avoid homonymy, it is nonsense to say that you can introduce a replacement name with its own type series. The name tulumbensis is thus not a ‘sp.nov.’ but a nomen novum. And the holotype of Clessinia cordovana striata Parodiz, 1939 (MACN-In 9127) becomes automatically the holotype of Clessinia tulumbensis! The “holotype IBN 883” and the paratype material mentioned in this paper has no status other than being vouchers for this study.

References:
Breure, A.S.H. & Romero, P.D., 2012. Support and surprises: a new molecular phylogeny of the land snail superfamily Orthalicoidea (Gastropoda, Stylommatophora) using a multi-locus gene analysis. – Archiv für Molluskenkunde, 141: 1–20.
Cowie, R.H. et al., 2004. The South American Mollusca of Johann Baptist Ritter von Spix and their publication by Johann Andreas Wagner. – The Nautilus, 118: 71-87.
Cuezzo, M.G. et al., 2018. From morphology to molecules: a combined source approach to untangle the taxonomy of Clessinia (Gastropoda, Odontostomidae), endemic land snails from the Dry Chaco ecoregion. – PeerJ, 6: e5986 (54 pp.).

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Omalonyx unguis in Argentina

Recently, Guzmán et al. reported on this species with the following abstract: “Omalonyx unguis (d’Orbigny, 1837) is a semi-slug inhabiting the Paraná river basin. This species belongs to Succineidae, a family comprising a few representatives in South America. In this work, we provide the first record for the species from Misiones Province, Argentina. Previous records available for Omalonyx in Misiones were identified to the genus level. We examined morphological characteristics of the reproductive system and used DNA sequences from cytochrome oxidase subunit I (COI) gene for species-specific identification. These new distributional data contribute to consolidate the knowledge of the molluscan fauna in northeastern Argentina”.

Schermafbeelding 2018-11-08 om 16.19.41

In the paper also figures of the shell and the genitalia are presented. The authors were likely unknown of the revisionary work of Vidigal et al. (2018), who showed that the correct name of this species is Omalonyx matheroni (Potiez & Michaud, 1835).

Reference:
Guzmán, L.B. et al., 2018. First record of the semi-slug Omalonyx unguis (d’Orbigny, 1837) (Gastropoda, Succineidae) in the Misiones Province, Argentina. – CheckList 14 (5): 705-712.

Ventania from Argentina

Pizá et al. just published a paper in which they redescribed the single Ventania species known from Argentina.

“Although the presence of apertural folds and lamellae is the most recognizable character of the Odontostomidae, some species lack them, mostly in Anctus Martens, 1860, Bahiensis Jousseaume, 1877 and Moricandia Pilsbry & Vanatta, 1898. Eudioptus avellanedae Doering, 1881 – a slender odontostomid species that lacks even the slightest trace of folds or lamellae in its shell aperture – was however transferred to Odontostomus by Pilsbry in 1902 on the basis of its building forward of the aperture-margins. It is currently placed in its own monotypic subgenus, Cyclodontina (Ventania) Parodiz, 1940, on the basis of about the same argument. In this paper we redescribe its shell morphology and, for the first time, describe the internal anatomy of the pallial complex and the reproductive and digestive systems. The presence of a spongy gland in the pallial complex; of a short penis sheath with no retractor muscle; of a bursa copulatrix duct longer than spermoviduct, and of an epiphallic gland strongly support the inclusion of this unusual species in Odontostomidae. The species is diagnosable by the sculpture of the protoconch, which is not smooth as previously described, but has waved axial ribs crossed by spiral lines in young specimens; the distinctive external and internal shape of the bursa copulatrix duct; the internal penis wall divided in three regions of different sculpture; the smooth inner wall of the vagina; the long and cylindrical epiphallus with a distal widening indicating the presence of an epiphallic gland, and the penis retractor muscle inserted in the distal end of a short flagellum. These characters support the validity of Ventania Parodiz, 1940, different from Cyclodontina Beck, 1837”.

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The first two authors are known to have published already a series of thorough papers on Odontotomidae of Argentina. This paper follows in this line and gives convincing arguments why Ventania should be considered a separate, monotypic genus.

Reference:
Pizá, J., Cazzaniga, N.J. & Ghezzi, N.S., 2018. Redescription of Ventania avellanedae (Stylommatophora: Odontostomidae), a land snail endemic to the Ventania Mountain System, Argentina. – Zoologia, 35: e17786 (11 pp.). DOI: 10.3897/zoologia.35.e17786

Ruminia decollata in Cordoba

Reyna & Gordillo just published a brief research note in which they report the finding of specimens of Ruminia decollata (Linnaeus, 1758) in Córdoba Province, Argentina.

According to these authors this snail is a potential host of roundworms that are common in dogs and cats, and thus may also affect susceptible humans. Moreover, this alien species may affect crops and horticultural products.

Reference:
Reyna, P. & Gordillo, S., 2018. First report of the non-native snail Rumina decollata (Linnaeus, 1758) (Subulinidae: Gastropoda) in Córdoba (Argentina): implications for biodiversity and human health. – American Malacological Bulletin, 36 (1): 150-152.

Invasive apple snails

This time not a terrestrial but a freshwater topic: apple snails, or the family Ampullariidae.
Joshi et al. have just published a book on the biology and management of invasive species of this group. The book contains 22 chapters, divided into three themes: General aspects of apple snail biology, Country specific reports, and Management and use.

In the second section two chapters deal with Pomacea canaliculata respectively in Argentina and Ecuador.

The Argentinan chapter is written by P.R. Martin et al., the abstract reads “Pomacea canaliculata is in many respects the best known species of apple snails (family Ampullariidae), although the available information is both fragmentary and geographically biased. Most studies in its non-native range have focused on applied aspects in managed or arti cial wetlands in various countries in Southeast Asia. In its natural range the emphasis has been on basic studies of its reproductive biology, ecology and behaviour in populations from small streams at the southernmost extreme of its distribution (Southern Pampas, Argentina). The extreme geographic position and the lotic nature of these populations may have biased some conclusions about the behavioural and ecological traits of P. canaliculata; contemporary evolution and genetic exchange may also have diversi ed these traits in the non-native range. Even though the ecological information from native populations may not be directly applicable elsewhere, it nevertheless remains as a necessary reference to understand the full potential of adaptation and spread of P. canaliculata to new environments around the world. Surprisingly enough, comparative studies of native and non-native populations of Pomacea spp. are almost lacking. This short review focuses on the distribution, thermal biology, aerial respiration, feeding, reproduction, phenotypic plasticity and shell shape of Pomacea canaliculata in its native range in Argentina.

The Ecuadorian chapter is M. Correoso et al.; the abstract is “This article characterises and analyses the presence of the alien invasive species Pomacea canaliculata in Ecuador, a pest present in many countries that has severe impacts on agriculture, human health and the natural environment. For the rst time, a list of the native species of the genus Pomacea in Ecuador is provided, as well as an occurrence map, based on review of existing (but few) bibliographic data, museum collections and recent eld work. There is a lack of information on other mollusc species in Ecuador, but there is the potential for ecological impact of P. canaliculata on the native mollusc fauna, especially other Pomacea species, which may already be in decline. Other biological threats and consequences are considered, highlighting the impacts that the invasion has had in this Andean country. Also, events that have occurred since the detection of the pest are reviewed, in particular, the decisions adopted by the rice agricultural sector in comparison with those reported by other countries facing a similar situation. The epidemiological role of P. canaliculata in Ecuador is analysed following confirmation that P. canaliculata can carry the nematode Angiostrongylus cantonensis, which causes eosinophilic meningitis. Cases of human infection and the possible routes of transmission are discussed, confirming that Ecuador was the first South American country to have cases of the disease. These results are compared with those for the giant African snail (Lissachatina fulica), a mollusc that can also transmit the disease. It is probable that native Pomacea species can also be infected with the nematode. Finally, a wide range of measures and management actions that should be considered, and possibly adopted, by Ecuador are proposed with the goal of controlling this dangerous pest.

Reference:
Joshi, R.C., Cowie, R.H. & Sebastian, L.S., 2017. Biology and management of invasive apple snails. Muõz: Philippine Rice Research Institute, 406 pp. Available at http://tinyurl.com/y8aw4htb

Cecilioides in Argentina

Diaz et al. recently published a new record of an introduced species for Argentina. “Cecilioides acicula (Müller, 1774), family Ferussaciidae, is native to the Palaearctic region but has been dispersed around the word by human activity. Here, we report the presence of this introduced species in La Plata city, Buenos Aires province, Argentina. This snail is largely subterranean and frequently is found in old graves in association with skeletal remains. Our samples were collected from sediments from the Municipal Cemetery of La Plata, Buenos Aires province, Argentina”.

Reference:
Diaz, A.C. et al., 2017. First record of Cecilioides acicula (Müller, 1774) (Mollusca: Ferussaciidae), from Buenos Aires province, Argentina. – CheckList, 13(2): 2096.

Two papers on CCP snails

Two papers were published, one very recently and one today, related to the material collected by the ‘Comisión Científica del Pacífico’ (CCP). This material was collected during an expedition that lasted from late 1862 to  early 1866 through several Neotropical counties. The material has been deposited in the Madrid museum and was originally studied by Hidalgo (terrestrial molluscs, marine gastropods) and Martínez (marine bivalves).

The terrestrial material has been restudied during a SYNTHESYS project last year, and has resulted in two papers. One dealing with the CCP material and the history of the expedition (Breure & Araujo, 2017), and one dealing with the publication date of Hidalgo’s main paper on the CCP material and related correspondence from him with Crosse in Paris (Breure & Backhuys, 2017).

The link to the first paper is here.

Update:
Due to an unfortunate coincidence at the proof stage (we unexpectedly received only one proof), the following corrections were not made in the published version:
Fig. 3 in the text (page 4) correspond to Fig. 2B
Fig. 4 in the text (page 5) correspond to Fig. 3A
Fig. 5 in the text (page 6) correspond to Fig. 3B
Fig. 6 in the text (page 6) correspond to Fig. 4A
Fig. 7 in the text (page 7) correspond to Fig. 4B
Fig. 8 in the text (page 9) correspond to Fig. 5A
Fig. 9 in the text (page 10) correspond to Fig. 5B
Fig. 10 in the text (page 12) correspond to Fig. 6A
Fig. 11 in the text (page 12) correspond to Fig. 6B
Then, after Fig. 11 in the text, appear Figs. 7A-7B (page 17) that actually correspond to the Figures 7A and 7B; later (page 17) appears Fig. 8G-8H that correspond to Fig. 8.
Finally, Fig. 27H does not depict Bostryx rouaulti as the wrong shell was photographed.

References:
Breure, A.S.H. & Araujo, R. The Neotropical land snails (Mollusca, Gastropoda) collected by the ‘Comisión Científica del Pacífico’. — PeerJ 5: e3065 (142 pp.).
Breure, A.S.H. & Backhuys, W. Science networks in action: the collaboration between J.G. Hidalgo and H. Crosse, and the creation of ‘Moluscos del Viaje al Pacifico, Univalvos terrestres’. — Iberus 35: 11–30.