Tag Archives: taxonomy

New Radiodiscus

Freshly pressed: a paper by Mike Rutherford describing a new species from Trinidad. “Radiodiscus hollidayi, a new species of Charopidae, is described from the island of Trinidad, Trinidad and Tobago. The description is based on conchological features alone: a tiny discoid shell with a distinct protoconch with 6–8 cordlets, fine ribs on the teleoconch, and a deep umbilicus. The snail is found in leaf litter and humus in a variety of forest habitats across Trinidad. A table compares a common set of measurements and characters across 27 other species of Radiodiscus“.

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A nice addition to the fauna of Trinidad, which still deserves an updated checklist on which the author is working.

Reference:
Rutherford, M.G., 2020. A new species of Radiodiscus (Gastropoda: Eupulmonata: Charopidae) from Trinidad and Tobago. – Archiv für Molluskenkunde 149(1): 67-74.

Forming a species name

While this is food for few, the subject may be interesting enough for those who find it cumbersome to dig through the rules of the ICZN Code when they need to name a new taxon. Vendetti & Garland has just published a practical guide, stating “The formation of scientific names for species may be challenging for modern systematists without a background in Latin or familiarity with the International Code of Zoological Nomenclature. Therefore, presented here are 10 pragmatic and simplified strategies for creating zoological species names. They are intended to demystify the derivation and construction of species names and facilitate the process of naming species for a broad audience of zoologists working in systematics”.

Their 10 strategies are the following:
1. As a Latin singular or plural noun in the genitive case;
2. As a Latin singular present participle active (PPA) in the nominative case;
3. As a Latin singular noun in the nominative case used in apposition;
4. As a non-Latin singular noun used in apposition;
5. Named after a person or persons, as a Latin singular or plural noun in the genitive case;
6. As a Latin singular adjective in the nominative case;
7. As a Latin singular perfect passive participle (PPP) in the nominative case;
8. For a geographic name, as a Latin singular adjective in the nominative case;
9. As compound word composed of Latin + Latin, Greek + Latin, or Greek + Greek word elements;
10. As an arbitrary combination of letters, singular or plural.

For each strategy they provide a clear explanation with examples from different phyla, and a practical application. In several cases with further examples, like this:

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Although it requires some sensitivity for linguistics, the overall impression is that with this paper naming a new taxon is do-able, even for those who did not have classes Latin and Greek at school. In this context I also like to draw attention to the paper ‘A name is a  name is a name’ by Peter Dance, who offers 19 additional viewpoints to naming a species.

References:
Dance, S.P., 2009. A name is a name is a name: some thoughts and personal opinions about molluscan scientific names. Zoologische Mededelingen Leiden 83(7): 565-576.
Vendetti, J.E. & Garland, R., 2020. Species name formation for zoologists: a pragmatic approach, Journal of Natural History 53(47-48): 2999-3018.

 

Annulariid phylogenetics

A recent paper by Watters et al. gives important insight in the relation of a group from the Annulariidae. Their abstract is as follows: “The subfamily Abbottellinae of the Annulariidae has been recognized as a speciose group in northern Hispaniola. This study, using phylogenetic (COI, 12S, H3), radular, and conchological characteristics, compared this group to other non-Hispaniolan annulariids to determine their wider associations and potential origin. Results indicate that the subfamily is related to the eastern Cuban Annularisca sensu lato and that genus should be moved to the Abbottellinae. The group dates from the time when eastern Cuba and northern Hispaniola were in close contact prior to tectonic movement. This is the first such zoo- geographic connection reported for the family. The subfamily is not related to any Jamaican taxa tested. The Abbottellinae also do not occur on the southern Tiburon/Barahona peninsulas of Hispaniola, which has a different geologic history from the north. The eastern Cuban and Bahamian genus Opisthosiphon sensu lato was also shown to be a member of the subfamily. The nominal genus Abbottella is further divided into new genera based on these results. The new genera Abbottipoma, Arenabbottella, Microabbottella, and Preclaripoma are described. The new species Rolleia simonaikeni is described, and Petasipoma is synonomized with Rolleia.“.

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Another paper from this very productive lab, of which its leading figure Tom Watters recently died. It shows how the molecules combined with the external morphology presents new insights in the taxonomy of a group and also elucidates the evolution and relationships with other Annulariids.

Reference:
Watters, G.T. et al., 2020. The subfamily Abbottellinae (Gastropoda: Annulariidae): origins, associations, and a review of the Hispaniolan taxa. – The Nautilus 134(1): 1-34.

Three short papers on Cuban land snails

While checking the site of the journal Poeyana, I found three short papers published last year: an area inventory (Franke & Fernandez), and two papers of Cerionidae (Suarez & Hernandez respectively de Armas).

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Abstract: Land snails of the Cerro de Yaguajay, Banes, Holguin. This paper provides information on the land snails of Cerro de Yaguajay, Banes. We account 22 species included in three orders and 17 families. The more represented families were Cepolidae and Helicinidae with five and four species respectively. The endemism was 84% and four threatened species were registered: Emoda blanesi, Eutrochatella (Microviana) spinopoma, Idiostemma alfredoi and Polymita muscarum. The 50% of the species inhabit at ground level, between leaf litter and rocks. The results provided data about the values of Cerro de Yaguajay as a regional site for conservation of land snails“.

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Abstract: Radula teratology of Cerion politum maisianum (Mollusca: Pulmonata: Cerionidae). A case of teratology is reported in the radula of a specimen of Cerion politum maisianum, an endemic mollusc species from Punta de Maisí, Guantánamo. The photograph of the dental cusps of a whole row of radular teeth taken at 400x magnification is shown, where the malformation is observed“.

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Abstract: Correction to the original spelling of Cerion milerae Suárez, 2018 (Mollusca: Pulmonata: Cerionidae). It is demonstrated that the original spelling of Cerion milerae Suárez, 2018, is incorrect, because it was dedicate to a man, not to a woman, and for this reason it is corrected as Cerion milerai Suárez, 2018, nomen emended, in accordance with the International Code of Zoological Nomenclature in effect. A map with the distribution of this species is also given“.

References:
Armas, L.F. de, 2019. Corrección a la grafía original de Cerion milerae Suárez, 2018 (Mollusca: Pulmonata: Cerionidae). – Poeyana 508: 44-45.
Franke, S. & Fernández V., A., 2019. 
Moluscos terrestres del cerro de Yaguajay, Banes, Holguín. – Poeyana 509: 14-17.
Suárez T., A. & Hernández C., I., 2019. 
Teratología en rádula de Cerion politum maisianum (Mollusca: Pulmonata: Cerionidae). – Poeyana 508: 42-43.

New Costa Rican euconulids

Just published: a paper by Barrientos with new data on Costa Rican Euconulidae. The abstract is as follows:

Introduction: The family Euconulidae is circumglobal, but only one subfamily, the Euconulinae, occurs in the American continent. Fourteen native euconulids, in three genera, have been reported from Costa Rica.
Objective: In this paper I describe Tikoconus, a new genus of Euconulinae endemic to Costa Rica.
Methods: I dissected alcohol-preserved euconulids collected in Costa Rica. I took photographs or electron micrographs or drew the shell, external anatomy, reproductive system, mantle cavity organs and radula.
Results: The genus Tikoconus can be recognized by its semislug appearance and very thin and often flexible subglobose to subglobose-depressed external shell. Other distinctive features of the genus are a lack of black dots on the mantle and the presence of at least some dark blotches on the subpedal groove band. Internally, the urethra has a Z-shaped prolongation that almost reaches the mantle collar. The reproductive system has a distinctive external C-shaped penial gland that surrounds half of the penis circumference and is attached to the penis and to the penial caecum, but not connected to them by ducts. Also, there is an internal mono- or bi-lobulated extension in the penis. The epiphallus has a verge that enters into the penis. The penial sheath surrounds part of the penis, the epiphallus base and the penial retractor muscle insertion, but leaves the penial gland and the penis caecum free. The gametolytic gland is absent. I described two new subgenera: Tikoconus with six new species-T. (T.) costaricanus sp.n. (type species), T. (T.) onca sp.n., T. (T.) andresi sp.n., T. (T.) katyae sp.n., T. (T.) alosii sp.n., T. (T.) subsilvanus sp.n.; and Bribriconus with only one species-T. (B.) thompsoni sp.n. All species have restricted distributions and are endemic to particular watersheds, except for T. costaricanus which occurs nearly throughout the central mountains of Costa Rican. This genus inhabits very wet, little disturbed tropical forests from 400 to 2 500 masl on the Atlantic slope and from 760 to 2 500 masl on the Pacific slope. The genus Velifera, the other semislug euconulid reported from Costa Rica, is kept as a valid taxon and I choose the specimen ANSP 48765 as lectotype of Velifera gabbi with the purpose of clarifying the application of the name to a taxon.
Conclusion: A new euconulid genus and seven species were described.

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This is thorough paper on this less-known family which occurs in different Neotropical countries. A key is included for the species of the new genus. The paper provides interesting data on the anatomy and ecology of these species, data which are hardly known for other representatives of this family in the Neotropics.

Reference:
Barrientos, Z., 2019. A new genus of semislugs (Stylommatophora: Euconulidae) from Costa Rica and a review of the genus Velifera (Stylommatophora: Euconulidae). Revista de Biologia Tropical, 67 (6): 1313-1358.

New Brazilian species

Recently published, Simone & Do Amaral studied snails collected on islands off the Brazilian coast and discovered new species.

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Their abstracts is as follows: “Three new species of Bulimulidae (Gastropoda, Pulmonata) are described, each one endemic to a different island off the São Paulo coast, showing a high degree of endemicity of these islands in terrestrial malacofauna. Drymaeus castilhensis occurs on Castilho Island, it is mainly characterised by the strong axial dark spots in the shell or in being totally pale beige, penis elongated, lacking any inner chambers or glands, and double ducts of albumen gland. Drymaeus micropyrus occurs on Queimada Pequena Island, it is mainly characterised by greenish-cream shell, with narrow axial spots, and single duct of albumen gland. Bulimulus sula is from Alcatrazes Island, its main features include a relatively cylindrical, featureless shell, bilobed penis and, mainly and remarkably, a genital appendix that looks like a small accessory penis. These three species are described and compared with similar species, and accounts on their biogeography”.

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The two species of Drymaeus, if presented as shells only and without locality data, are so similar that would have doubted them to be two different taxa. But the anatomical differences evidently show that cannot be conspecific. Also the Bulimulus species is anatomically peculiar with the reported “small accessory penis”.

Reference:
Simone, L.R.L. & Amaral, V.S. do, 2018. Insular life: new endemic species from São Paulo oceanic islands, Brazil (Pulmonata, Bulimulidae), as example of endemicity. – Journal of Conchology, 43(2): 167-187.

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

New Cuban Cerion

In a not so current journal, a new species of Cerion was just described from Cuba.

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Cerion milerae sp. nov. is described from the type locality Punta Bejuquera, Gibara, Holguín province, Cuba. It is compared conchologicaly with Cerion paucicostatum paucicostatumCerion paucicostatum harringtoni and Cerion caroli aedilii. Anatomically it is compared with Cerion paucicostatum paucicostatum. With its description the number of species known from Cuba is increased to 148 and to 35 the number of species and subspecies known from Holguín province. An extensive survey in the zone showed that Cerion milerae sp. nov. is microlocalized, associated to Bayhops (Ipomoea pes-caprae), in sandy substrate”.

Reference
Suárez, A., 2018. Especie nueva de Cerion (Mollusca: Pulmonata: Cerionidae) de Holguín, Cuba. – Novitates Caribaea, 12: 43-48.

Xolotrema and the collation of Ferussac’s ‘Histoire naturelle…’

Harry Lee regularly adds insightful tidbits which go way beyond the limited distribution of the home-made journal in which he publish them. One such tidbit is the correct publication date of a Polygyrid snail occurring in Florida and described by Férussac. While has has struggled to get everything right, he now presents an updated collation of Férussac’s Histoire naturelle…, which deserves a wider audience. Reason why I copy his whole article here in this blogpost.

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Reference:
Lee, H.S., 2018. Xolotrema denotatum (Férussac, 18xx), its iconography and taxonomy – resolution. – Shell-O-Gram, 59 (4):2-4.

Taxonomy of Omalonyx

A group of Brazilian authors have made a comprehensive study on the succineid genus Omalonyx, with interesting results.

“The genus Omalonyx d’Orbigny, 1837, includes neotropical semi‐aquatic succineid slugs and comprises six recognized species to date. Field surveys across continental South America recovered five of the six recognized species. According to the morphological characters traditionally included in Omalonyx descriptions, the specimens were tentatively identified as O. matheroni, O. pattersonae, O. convexus, O. geayi and O. unguis. Employing sequences of mitochondrial cytochrome oxidase I (COI) alone or combined with the nuclear second internal transcribed spacer (ITS2) in discovery methods of species delimitation (GMYC and STACEY) led to species delimitation hypotheses that, except for unambiguously supporting O. convexus, have no correspondence to morphologically based assignments. To choose the delimitation model that best fit our data, the hypotheses recovered by GMYC, STACEY and morphology and created by merging species recovered by those methods had their marginal likelihood estimated and compared using the Bayes factors. The best‐supported hypothesis distinguished two species besides O. convexus: one widespread over most of South America and the other restricted to Rio de Janeiro State, Brazil. Furthermore, the pattern of genetic structuring supports pathways connecting the Amazonian and Atlantic forests. This pattern is similar to that observed in terrestrial taxa (e.g., forest‐dwelling small mammals) and is different from the pattern for fully aquatic taxa.”

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This is a well-executed study that uses different methods to formulate several hypotheses. The best-supported one leads the authors to conclude that there are two species to be recognised: O. convexus (Martens, 1868) and O. matheroni (Potiez & Michaud, 1835). This result is interesting, the more since this group is extremely difficult to study using the morphology alone. Such integrative studies are thus the way forward, and should be attempted also for other groups of Neotropical snails.

 

Reference:
Vidigal, T.H.D.A. et al., 2018. Integrative taxonomy of the neotropical genus Omalonyx (Elasmognatha: Succineidae). – Zoologica Scripta, 47 (2): 174-186.