Drymoreomys albimaculatus, Percequillo & Weksler & Costa, 2011

Percequillo, Alexandre R., Weksler, Marcelo & Costa, Leonora P., 2011, A new genus and species of rodent from the Brazilian Atlantic Forest (Rodentia: Cricetidae: Sigmodontinae: Oryzomyini), with comments on oryzomyine biogeography, Zoological Journal of the Linnean Society 161 (2), pp. 357-390 : 368-369

DRYMOREOMYS ALBIMACULATUS GEN. ET SP. NOV. ( FIGS 1–6 )

Holotype: MZUSP 34716 , an adult female collected by Meika A. Mustrangi (original field number MAM 8 ; previous collection number MVZ 182088 ), 21.vii.1992. The holotype consists of an undamaged skin, skull, and postcranial partial skeleton. A liver tissue sample is preserved in ethanol in the Museum of Vertebrate Zoology tissue collection, under original field number MAM 8 . Irbp and cyt- b sequence data are available in GenBank under the accession numbers GU126515 and GU126516 , respectively.

External and selected skull dimensions (in mm) of holotype are as follows: HB = 149, LT = 176, HF = 28, Ear = 20, Wt = 57, CIL = 30.67, LD = 8.56, LM = 5.25, BM1 = 1.49, LIF = 6.33, BIF = 2.82, BR = 5.99, LN = 12.37, LPB = 5.33, BBP = 3.07, LIB = 17.84, ZB = 5.69, BZP = 2.65, OFL = 11.37, BB = 4.87.

Paratypes: We assign all specimens herein studied (see Specimens examined below) as paratypes of D. albimaculatus .

Type locality: Brazil, Estado de São Paulo, Município de Ribeirão Grande, Parque Estadual Intervales, base do Carmo , 700 m; 24°20′S, 48°25′W (collecting field coordinates given by the collector). Originally known as Fazenda Intervales, the Parque Estadual Intervales is situated between the valleys of Rio Paranapanema (a tributary of Rio Paraná) and Rio Ribeira de Iguape (an important Atlantic Forest river drainage that flows directly to Atlantic Ocean), on the slopes of Serra de Paranapiacaba .

Distribution: As for the genus, i.e. known currently from a few localities in the eastern Slopes of the Serra do Mar Range in São Paulo and Santa Catarina, Brazil ( Fig. 1 ). There is a gap in the distribution of collecting localities of D. albimaculatus on Paraná state and we interpret this as a sampling artefact rather than actual evidence of disjunct populational distribution.

Etymology: From the Latin albus (white) and the Latin maculatus (spot, stain), in reference to the patches of entirely white fur on the gular, thoracic, and inguinal regions.

Morphological description and diagnosis: Same as for the genus.

Comments: The first three known specimens of Drymoreomys albimaculatus were originally obtained by Dr Meika Mustrangi during the austral winter of 1992 at Parque Estadual Intervales, São Paulo, and were housed at the Museu de Zoologia da Universidade de São Paulo and the Museum of Vertebrate Zoology. Another specimen was trapped by Drs Julio Voltolini and Jorge Cherem at the Parque Estadual da Serra do Tabuleiro, in Santa Catarina in the same year as Mustrangi’s specimens and deposited at the Universidade Federal de Santa Catarina. More recently, independent inventories throughout the Atlantic Forest in the states of São Paulo ( Pardini & Umetsu, 2006; Bueno, 2008; and also unpublished data and vouchers available at Museu de Zoologia da Universidade de São Paulo) and Santa Catarina (unpublished data and vouchers available at the Fundação Universidade Regional de Blumenau, Santa Catarina), sampled several other specimens that could be confidently assigned to D. albimaculatus . All specimens remained unstudied in museum drawers and the ecological data obtained from those specimens were not published, pending a formal description for both the genus and species.

Specimens examined: BRAZIL: SÃO PAULO: Cotia, Reserva do Morro Grande : F: MZUSP BS 1441 (s, sk) , AB 397, 398, 422, 423, 698 (sk, fl). Bananal, Estação Ecológica de Bananal : F: MZUSP 33782 (s, sk, car) Ribeirão Grande , Mina Limeira : M: MZUSP RG 47 ; F: MZUSP RG 48 (sk, fl) . Ribeirão Grande , Fazenda Intervales, Carmo : F: MVZ 182089 , MZUSP 34716 (holotype of D. albimaculatus ), MZUSP MAM 15 (s, sk, skel) . Salesópolis, Estação Biológica de Boracéia : M: MZUSP BO 41 , 42 , 44 , plus three specimens without field number; F: MZUSP BO 24 , 43 , plus two specimens without field number (sk, fl). SANTA CATA- RINA: Parque Estadual da Serra do Tabuleiro : UFSC 860 (s, sk) . Blumenau, Parque Natural Municipal Nascentes do Garcia : M: FURB 9621, 9664, 9756, 9787, 9833, 9838, 9862, 9871, 9902, 12044 (s, sk); F: FURB 9792, 9794, 9831, 9869, 9903 (s, sk); U: FURB 9666, 9743, 9962 (s, sk). Blumenau, Parque Natural Municipal Nascentes do Garcia, Terceira Vargem do Ribeirão Garcia , Vale do Espingarda : F: FURB 6267 (s, sk).

Figures

Figure 1. Known collection localities of Drymoreomys albimaculatus gen. et sp. nov. in south-eastern Brazil; the open circle indicates the type locality of this species. Inset: South America. See Gazetteer (Appendix 1), where numbers are associated with collection localities.

Figure 2. Ventral view of the dried skin of the holotype of Drymoreomys albimaculatus gen. et sp. nov. MZUSP 34716 from Parque Estadual Intervales, São Paulo, showing the gular and pectoral patch of entirely white hairs.

Figure 3. Cranium (dorsal, ventral, and lateral views) and mandible (lateral view) of the holotype of Drymoreomys albimaculatus gen. et sp. nov. MZUSP 34716, from Parque Estadual Intervales, São Paulo (condylo-incisive length 30.67 mm).

Figure 4. Detail of the ventral view of the cranium of Drymoreomys albimaculatus gen. et sp. nov., showing the incisive foramina with lateral margins abruptly constricted anteriorly near the premaxillary-maxillary suture [left specimen, MZUSP BO 42, from Estação Biológica de Boracéia, São Paulo; length of incisive foramen (LIF): 5.71 mm] and with abruptly constricted lateral margins, near the posterior border (right specimen, MZUSP BO 41, also from E. B. Boracéia; LIF: 5.74 mm).

Figure 5. Detail of the ventral view of the cranium of Drymoreomys albimaculatus gen. et sp. nov., showing the palate, the anterior margin of mesopterygoid fossa, and the sphenopalatine vacuities of the same specimens depicted in previous figure [MZUSP BO 42, length of palatal bridge (LPB): 5.03 mm; MZUSP BO 41, LPB: 5.34 mm].

Figure 6. Molar series in occlusal view of Drymoreomys albimaculatus gen. et sp. nov.: Left pair: upper (left) and lower (right) molars of the holotype, MZUSP 34716 [length of molars (LM): 5.25 mm, breadth of M1 (BM1): 1.49 mm]; Right pair: upper (left) molar series of the paratype, MZUSP BO 43 (LM: 4.90 mm, BM1: 1.35 mm), from Estação Biológica de Boracéia, São Paulo, and lower (right) molar series of the paratype, MZUSP AB 422 (LM: 4.97 mm, BM1: 1.39 mm), from Reserva do Morro Grande, São Paulo.