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Early in August, 2010, I came to the conclusion that
Phosinella pulchra (C.B. Adams, 1850: 114), as interpreted by Redfern (2001:
34; plate 17, fig. 141), was a distinct biotaxon. A close look at the
uncharacteristically well-preserved holotype, including its protoconch (Clench
and Turner, 1950: plate 33, fig. 8) confirms Redfern's identification and
places its synonymy with P. cancellata (Philippi, 1847), as asserted by
Desjardin (1949: 204) and Ponder (1985: 83) in serious doubt. Since the C.B.
Adams taxon is the type of Phosinella Mřrch, 1876; see
http://bhl.ala.org.au/item/53851#page/73/mode/1up
(subsequent designation by Nevill, 1885: 73, 83),** this is no small taxonomic
matter.
Delving further, I found that the figures of "Rissoina
(Phosinella) cancellata Philippi" in Ponder (1985: plate 135, figs. A
and B) were not consistent with Redfern's clearly-expressed concept of that
taxon but fit that of his P. sagraiana (d'Orbigny, 1842); see Redfern (op.
cit. 34; plate 17, figs. 140, 142, respectively) and above.
Working independently Rolán and Fernández-Garcés (2010)
agreed with this assessment, but they took the research a bit further and
located the holotype of R. cancellata at the Zoologische Museum, Berlin.
This specimen is actually not at all the species Redfern described and figured;
it is clearly synonymous with R. sagraiana. They considered Redfern's "R.
cancellata" a theretofore unnamed species and dubbed it Rissoina
cancellina (see above).
An additional cloud over Adams' Rissoa pulchra was
nomenclatorial: it is a primary junior homonym of Rissoa pulchra Forbes,
1844, and neither I nor Rolán and Fernández-Garcés (2010) could find a synonym
to recruit into usage. However, those workers argued that the Forbes taxon was
not identifiable and its name had been used much less frequently than R.
pulchra C. B. Adams, 1850, so they proposed protecting its availability.
Stepping back to a generic perspective, we can appreciate
Phosinella in the western Atlantic includes the four taxa of Redfern (2001:
plate 17, figs. 140-143): the three mentioned above and P. redferni
(Espinosa and Ortea, 2002), which is based on the former author's Rissoina
sp. B (Redfern, op. cit. 34, plate 17, figure 143); see above. To those
we may add P. fenestrata (Schwartz, 1860) recently redescribed by
Rolán and Fernández-Garcés
(2009) and Rissoina fenestrata of Leal (1991: 75-76; pl. 9, figs. A, B)
not of Schwartz, 1860.
**
Two years later the type species was restricted to Rissoina sagraiana
d’Orbigny, 1842 by Tryon (1887: 320; see
http://tinyurl.com/443zyuh),
but the die had been cast.
Adams, C.B., 1850. Descriptions of
supposed new species of marine shells which inhabit Jamaica. Contributions to Conchology 7: 109-123. April.
<http://www.archive.org/details/contributionstoc00adam>;
<http://www.biodiversitylibrary.org/item/48996#page/124/mode/2up>
Clench, W.J. and R.D. Turner, 1950. The western Atlantic marine mollusks
described by C. B. Adams. Occasional Papers on Molluscs 1(15): 233-403
incl. pls. 29-49. June 26.
Desjardin, M., 1949. Les Rissoina de l’île de Cuba. Journal de
Conchyliologie 89(4): 193-208 + pls. 9-10.
Leal, J.H., 1991. Marine prosobranch gastropods from oceanic islands off
Brazil. Backhuys, Oegstgeest, Netherlands. x + pp. 1-418 incl. 22 pls.
Mřrch, O.A.L., 1876. Synopsis molluscorum marinorum Indiarum occidentalium
imprimis insularum danicarum. Malakozoologische Blätter 23: 45-58,
87-143.
Nevill, G. 1885. Hand list of Mollusca in the Indian Museum, Calcutta. Part
II. Gastropoda. Protobranchia-Neurobranchia (cont'd.). Government Printer,
Calcutta. x + 306 pp.
Ponder, W. F., 1985. A review of the genera of the Rissoidae (Mollusca:
Mesogastropoda: Rissoacea). Records of the Australian Museum supplement 4:
1-221.
Rolán, E. and R. Fernández-Garcés, 2009. New information on Cuban Rissoina
(Mollusca: Rissoidae) 1. Rissoina fenestrata and R. vanderspoeli.
Novapex 10(2): 59-64. 10 June.
Rolán, E. and R.
Fernández-Garcés, 2010. New information on the Caribbean Rissoina (Gastropoda,
Rissoidae) of the group R. sagraiana-cancellata, with the description of
a new species. Iberus 28(1): 79-89.
Schwartz von Mohrenstern, G., 1860. Über de familie der Rissoiden insbesondere
die gattung Rissoina. Denkschriften der
Mathematisch-Naturwissenschraftlichen. Classe der Kaiserlichen Akademie der
wissenschraften 169: 70-188, pl. 1-11. |
