Cristafrons Feldmann, Tshudy & Thomson 1993
Genus Cristafrons Feldmann, Tshudy & Thomson, 1993 Cristafrons Feldmann, Tshudy & Thomson, 1993: 31. Type species. Cristafrons praescientis Feldmann, Tshudy & Thomson, 1993, by monotypy. Remarks. Cristafrons shows an unusual set of characters. Feldmann et al. (1993: 31) remarked that the...
| Main Authors: | , , , , |
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| Format: | Other/Unknown Material |
| Language: | unknown |
| Published: |
2012
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| Online Access: | https://zenodo.org/record/5250452 https://doi.org/10.5281/zenodo.5250452 |
| Summary: | Genus Cristafrons Feldmann, Tshudy & Thomson, 1993 Cristafrons Feldmann, Tshudy & Thomson, 1993: 31. Type species. Cristafrons praescientis Feldmann, Tshudy & Thomson, 1993, by monotypy. Remarks. Cristafrons shows an unusual set of characters. Feldmann et al. (1993: 31) remarked that the general form was similar to species of Notopocorystes. Cristafrons can be readily distinguished from Palaeocorystidae by the prescence of only a single lateral spine and a narrow, non-bifurcate rostrum. The well-defined cervical groove and the hepatic and postfrontal areolations, however, are unusual for Raninoidea, whereas those features are commonly found in Palaeocorystoidea. The thoracic sternum of Cristafrons is ‘not cleft longitudinally’, i.e., the medial line is absent (sternites 1‒5 are described), members of Raninoidinae typically having a medial line up to sternite 5 (Fig. 44C, D). It is unlikely that Cristafrons belongs to Ranininae, which has wider carapaces and two wide lateral teeth. Exposed pleurites are not described in the type series: they may be concealed by matrix or were overlooked in the original description, which states that the type specimens ‘are deposited in the Natural History Museum, London’ (Feldmann et al. 1993: 33), where only two specimens could be traced by us. The majority of the type series appears to have been forwarded to the British Antarctic Survey (BAS), under ‘ Cretiscalpellum praescientis ’ (see also http://www.antarctica.ac.uk/bas_research/data/access/fossildatabase/filter.php?taxonKeyword= CRUSTACEA). A re-examination of the type series is called for in order to resolve the precise taxonomic placement of Cristafrons. Published as part of Van Bakel, Barry W. M., Guinot, Danièle, Artal, Pedro, Fraaije, René H. B. & Jagt, John W. M., 2012, A revision of the Palaeocorystoidea and the phylogeny of raninoidian crabs (Crustacea, Decapoda, Brachyura, Podotremata) 3215, pp. 1-216 in Zootaxa 3215 (1) on page 100, DOI:10.11646/zootaxa.3215.1.1, http://zenodo.org/record/5248640 |
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