Diplomesodon sonnerati Cheke, 2018

Cheke, Anthony S. & Hume, Julian P., 2018, The Réunion Fody and Sonnerat’s Shrew and the validity of scientifically naming animals described without physical types, Zootaxa 4382 (3), pp. 592-600 : 595-596

Sonnerat’s Shrew Diplomesodon sonnerati Cheke sp.nov.

Synonymy subsequent to Cheke (2012)

Diplomesodon sonnerati Tkach et al. 2013: 397 .

The shrew is described by Sonnerat in two passages, one a general account of wildlife in southern India, the other the specific diagnosis, accompanied by a crude pen-sketch ( Fig.1 ). The passages (my translation) are as follows:

From Deloche & Ly-Tio-Fane (2010) Chapter 4: "On the Indian monsoons; [and] productions of the Coromandel coast", p.111, after describing the ubiquitous house or musk shrew Suncus murinus (Linnaeus) and its offensive scent:

One sometimes encounters with these rats musqués 1 a particular species that has all the characters of a shrew, but it does not generate a smell of musk; it is also larger, shiny black with a white band on the middle of the body.

From Chapter 13, "New items relating to natural history", p.314, Sonnerat's diagnosis and comparison:

This shrew is five and a half inches 2 [149 mm] from the head to the base of the tail; the tail is one inch one line [29 mm] in length; the eyes are almost imperceptible and appear only as two little black points. It is entirely a handsome black, with a transverse white band across the middle of the body; all its fur is silky; the female is smaller and has the same transverse white band, but all that is black in the male is a clear grey in the female.

This shrew has the shape and all the characters of the rat musqué, but it never inhabits houses like it does, nor does it give off any musky smell; it is also larger; it stays hidden during the day in holes and only appears at night to seek food; I found it in fields a few leagues1 from Pondicherry.

The text around the sketch adds '5 toes' written next to both front and rear legs, 'two longer incisor teeth' against the upper jaw, 'ditto' (i.e., the same) against the lower jaw, and the drawing itself shows large protruding incisors in both jaws, all features typical of shrews—i.e. there is no question that Sonnerat's animal was indeed a shrew. The tail is shown as stout and stubby, similar to that of Diplomesodon pulchellum . The rest of the text by the sketch reprises the edited version of the description.

Sonnerat's very adequate diagnosis is, together with his illustration, sufficient without further embellishment to establish this animal as a species new to science which I am naming Diplomesodon sonnerati sp.nov. It is distinguished from all shrews, apart from D. pulchellum , by the white dorsal patch, and from D. pulchellum by its much larger size, sexual dimorphism, saddle-shaped white patch (not elongated along the back), and dark (not white) underparts.

Holotype: The individual shrew sketched by Sonnerat ( Fig. 1 ) is designated as holotype, and all other examples seen and discussed by Sonnerat, including the grey females, as paratypes.

Measurement: Total length around 149mm.

Type locality & Distribution: Vicinity of Pondicherry / Puducherry, southern India.

Etymology: Named after Pierre Sonnerat who discovered the species.

The generic attribution is tentative, based on the pelage similarity between this animal and D. pulchellum . Sonnerat's shrew is however twice as long as the Central Asian species (head+body 54–76 mm, Nowak 1999), and if regularly larger than Suncus murinus , as Sonnerat claimed, would make it the world's largest shrew. S. murinus ranges up to 150 mm ( Nowak 1999) or 160 mm (Alfred et al. 2006) in head and body length, making it roughly the same size as D. sonneratii as described by Sonnerat. DNA analysis ( Dubey et al. 2008) nested Diplomesodon within the speciose genus Crocidura , though the researchers decided, against the usual practice, to "keep this morphologically highly distinctive taxon in its own genus, although this would render Crocidura a paraphyletic taxon". Sonnerat’s shrew may not be extinct and should be searched for in southern India – if rediscovered, voucher specimens of each gender should be collected, and one specimen designated as a neotype.

Figures

FIGURE1. Sonnerat's sketch,with associated inscriptions, of the "musaraigne noire à bande blanche" [blackshrew withwhite band] from his manuscript Nouveau voyage aux Indes, held as Item No. PX*D83 p.32 in the Mitchell Library, Melbourne. Published by permission of the New South Wales State Library; the sketch was not reproduced in Deloche & Ly-Tio-Fane (2010). The vertical writing is show-through from the other side of the paper; it has been digitally softened [from Cheke 2012].