Tag Archives: micro-CT

New Carychium from Panama

A recent paper by Jochum et al. described a new species of the micro-mollusc genus Carychium using modern CT-scanning.

The abstract reads: “Five years ago, the Panamanian evolutionary lineage (EL) C12 was uncovered along with four other ELs in an integrative phylogenetic investigation of worldwide Carychiidae. Since EL C12 lacked shell material post-molecular analysis to serve as a museum voucher, it remained undescribed. Now, after recent collection efforts of C12 and the congener, Carychium zarzaae Jochum & Weigand, 2017 at their original Panamanian sites, C12 is morphologically described and formally assigned the name, Carychium panamaense Jochum, sp. n. In sync with recent taxonomic treatment of the genus, computed tomography (CT) is used in this work to differentiate shells of C. panamaense sp. n. from geographically-proximal, Caribbean, North and Central American congeners. Recent material of topotypic Carychium jardineanum (Chitty, 1853) and undamaged C. zarzaae were additionally CT-scanned and assessed in the comparative analyses”.

Schermafbeelding 2018-12-15 om 21.59.09

CT-scanning is a promising technique, especially for molluscs with internal folds or dents, and for micro-molluscs. Also anatomical details may be imaged and reconstructed in this way, as was previously shown in this proof of principle.

Schermafbeelding 2018-12-15 om 22.00.23

Reference:
Jochem, A. et al., 2018. Fulfilling the taxonomic consequence after DNA Barcoding: Carychium panamaense sp. n. (Eupulmonata, Ellobioidea, Carychiidae) from Panama is described using computed tomographic (CT) imaging. – ZooKeys, 795: 1-12.

New Carychium species

Recently Jochum et al. published on Carychium species from the Nearctic and Neotropical regions, i.e. southeastern U.S.A., Belize and Panama. This add substantially to the known distribution of this genus in Central America.

The abstract reads: “Three new species of the genus Carychium O.F. Müller, 1773, Carychium hardiei Jochum & Weigand, sp. n., Carychium belizeense Jochum & Weigand, sp. n. and Carychium zarzaaeJochum & Weigand, sp. n. are described from the Southeastern United States, Belize and Panama, respectively. In two consecutive molecular phylogenetic studies of worldwide members of Carychiidae, the North and Central American morphospecies Carychiummexicanum Pilsbry, 1891 and Carychium costaricanum E. von Martens, 1898 were found to consist of several evolutionary lineages. Although the related lineages were found to be molecularly distinct from the two nominal species, the consequential morphological and taxonomic assessment of these lineages is still lacking. In the present paper, the shells of these uncovered Carychium lineages are assessed by comparing them with those of related species, using computer tomography for the first time for this genus. The interior diagnostic characters are emphasized, such as columellar configuration in conjunction with the columellar lamella and their relationship in context of the entire shell. These taxa are morphologically described and formally assigned their own names”.

They used micro-CT scanning to make the inner shell structures visible, which is an excellent and non-destructive way of doing.

Reference:
Jochum, A. et al., 2017. Three new species of Carychium O.F. Müller, 1773 from the Southeastern USA, Belize and Panama are described using computer tomography (CT) (Eupulmonata, Ellobioidea, Carychiidae). – ZooKeys, 675: 97-127.
[open access: https://zookeys.pensoft.net/article/12453/]

New paper published

Together with my colleague Corey Whisson, just published:

W&B2016a

A paper with a description of one new species is nothing to be taken too serious, but we are proud to present a novel way of (non-)dissection to study the genitalia: applying micro-CT and reconstruction with dedicated software. As far as we know this is one of the first times this method is applied to (land) molluscs in the context of describing a new species.

W&B2016b

Although the results presented here are satisfying, it is not necessarily a quick method and it is also quite laborious. However, in the case of a single or just a few specimens, this may be an alternative for destructive dissection. In this paper we show it as a ‘proof of principle’ for the application of this method.

Reference:
Whisson, C.S. & A.S.H. Breure, 2016. A new species of Bothriembryon (Mollusca, Gastropoda, Bothriembryontidae) from south-easternmost Western Australia. — ZooKeys 581: 127–140.