Calomys cerqueirai, Bonvicino, Cibele R., De, João A. & Gentile, Rosana, 2010

Bonvicino, Cibele R., De, João A. & Gentile, Rosana, 2010, A new species of Calomys (Rodentia: Sigmodontinae) from Eastern Brazil, Zootaxa 2336, pp. 19-25 : 27-31

Calomys cerqueirai new species

Holotype. An adult male (MN 71971) consisting of skin, skull, mandible, partial postcranial skeleton and ethanol-preserved liver tissue sample, field number LBCE 5556 ( Fig. 5 ). It was collected by R. Gentile on July 30, 2003, in grassy vegetation along a small stream at the type locality. The liver sample is stored at the Laboratório de Biologia e Parasitologia de Mamíferos Reservatórios Silvestres, Instituto Osvaldo Cruz- FIOCRUZ, Rio de Janeiro, under original field number LBCE 5556.

Paratypes. Two young males (MN 71972, 71973) consisting of skin, skull, mandible, partial skeleton and ethanol-preserved liver tissues, field numbers LBCE 5579 and 5583 collected along “Córrego Café” beyond the city center (19º02’33”S, 41º49’33”W).

Type locality. Margins of “Buraco do Cachorro” stream, situated near the head of “Café” stream, close to Capitão Andrade city center (19º04’35”S, 41º52’30”W), Capitão Andrade Municipality, state of Minas Gerais, Southeastern Brazil.

Capitão Andrade is a small city situated in a hilly region approximately 230 meters above sea level, in a characteristic rural landscape. It is located in a transitional zone between the Atlantic Forest and Cerrado morphoclimatic domains (Ab’Saber 1970), with predominant semi-deciduous tropical forest vegetation, in the Rio Doce Basin. The “Morro do Café” hill separates two main streams, “Café” and “Perdida”, which run across the municipality and flow into the Rio Doce, 20 km beyond the municipality’s center. Specimens were captured in rural areas along streams. Transects were characterized by open vegetation, predominantly grass, shrubs and scattered trees, since the original forest vegetation has been removed even on hills, which are now used for farming. This study was conducted during winter (July), when the vegetation was very dry, except alongside the streams. The three animals were captured in grassy vegetation, less than 2 meters from the stream margin.

Other specimens. Two specimens (GenBank accession numbers DQ447275 and DQ447276 ) from Lagoa Santa, Minas Gerais state, were not examined, but form a monophyletic clade with Capitão Andrade specimens, and one of them ( DQ447276 ) shares the same cytochrome b haplotype with the holotype (MN 71971) and the paratype MN 71972 of C. cerqueirai . To derive the karyotype of Lagoa Santa specimens (2n=36, FNa=66) and Capitão Andrade specimens (2n=38, FNa=66), one centric fusion involving two acrocentric pairs, or a centric fission involving one biarmed pair, is necessary. These specimens from Lagoa Santa were karyotyped by Geise et al. (1996), and sequenced by Almeida et al. (2007).

Etymology. This species is named after Dr. Rui Cerqueira for his long-standing dedication to the development of Brazilian Mammalogy.

Diagnosis. A large sized Calomys species with tail shorter than head and body, overall dorsal coloration light brown-yellowish, orange snout, and tail sharply bicolored. This species has five autapomorphic sites in relation to the sequences of the other Calomys species analyzed, in bases 189, 297, 423, 879, 1122 of the cytochrome b gene.

Measurements. See table 3.

Distribution. Known from the type locality and from Lagoa Santa, Minas Gerais state, Brazil.

Morphological description. A small-sized sigmodontine rodent ( Table 3 ) with tail shorter than head and body (75-87% of head and body length), moderately long and narrow hind feet, and small, rounded pinnae (16-18% of head and body length). Dorsal pelage is soft and dense, Cinnamon-Brown overall. Head color as on dorsum, but hairs surrounding nose Mars Yellow to Ochraceous-Tawny ( Fig. 6 ). Two types of hairs of similar length (8-10mm) present on dorsum: a rather homogeneously melanic type and a banded type. On head and dorsum, banded hairs have a long plumbeous base (7mm) and an Ochraceous-Tawny distal band. Melanic hairs are entirely black distally and mixed with banded hairs, producing the Cinnamon-Brown tone of the dorsum. Body laterals slightly lighter than dorsum due to the reduction of black guard hairs. Ventral pelage well delineated from laterals, covered with whitish hairs with gray bases. Pinnae internally covered by entirely Orange hairs, or hairs with long Orange bands, and externally covered by sparse brownish hairs. Patch of completely white hairs behind the ear. Fore- and hindfeet dorsally furred with entirely white hairs; silvery ungual tufts present on distal phalanxes of digits 2-5 in manus and digits 1-5 in pes. Tail sharply bicolor, with white hairs ventrally and dark hairs dorsally.

Cranial characters: skull with relatively short rostrum and laterally expanded braincase. Frontal bones with anteriorly convergent lateral outlines and supraorbital edges, but without distinct supraorbital crests. Nasals short. Zygomatic plate slightly projected anteriorly. Zygomatic notch moderately deep and broad. Incisive foramina long, reaching line of M1 protoflexus. The bony palate extends behind the end of upper molar row by a distance about equal to the length of M3, and bears one pair of posterolateral palatal pits.

(mm) – of Calomys sp.n. and selected samples of C. expulsus , C. callosus , C. callidus , C. tocantinsi , and C. tener from

Brazil. VAR = variables, see material and methods for abbreviations. * = CT (body and tail length). F = females, M =

males.

Narrow mesopterygoid fossa with U-shaped anterior notch. Sphenopalatine vacuities well developed. Parapterygoid fossae shallow and very large. Posterior openings of oval foramina large, without an alisphenoid strut. Hamular process delimiting a small postglenoid foramen and a large subsquamosal fenestra. Squamosal alisphenoid groove leading to small sphenofrontal foramen, and large stapedial foramen indicating a primitive carotid circulation pattern ( Voss 1988). The lateral wall of the mastoid is perforated by a medium sized fenestra.

Dental characters: Incisor opisthodont, upper series (M1-M3) parallel sided. A shallow anteromedian flexus in M1 divides the anterocone into subequal anterolingual and anterolabial conules. M2 squared and M3 small and rounded.

Karyotype. 2n=38, FNa= 66 in the holotype (see results), and 2n=36, FNa= 66 in specimens from Lagoa Santa ( Geise et al. 1996).

Comparisons. see discussion.

Natural history. All specimens were captured in rural areas along streams, in grassy vegetation, less than 2 meters from the stream margins. The holotype was infested with four individuals of Taenia sp., and 113 of Hepsilon sp.; MN 71973 (LBCE 5583) was infested with unidentified nematodes, and MN 71971 (LBCE 5556) with 62 individuals of Hepsilon sp. and four specimens of an unidentified nematode.

Figures

FIGURE 5. Dorsal, ventral and lateral views of skull, and lateral view of mandible of Calomys sp. n. holotype (male MN 71971).

FIGURE 6. Enlarged dorsal view of heads of C. expulsus (MN 71962, left) and C. cerqueirai (holotype, MN 71971, right).

Tables

TABLE 3. Descriptive statistics of measurements – mean (mm), sample size (in parentheses) and range of variation

VA R	Calomys sp.n.	C. expulsus	C. callosus	(F) C. callidus	(M) C. callidus	(F) C. tocantinsi	(M) C. tocantinsi C. tener	C. tener
HB	99 (2) 86–112	99.7 (211) 64–122	98 (27) 83–123	173.8*(12) 160–194	182.7*(25) 155–210	90.1 (10) 77–105	91.8 (8) 79–116	77.5 (10) 74–88
T	80 (2) 75–85	72.1 (21) 45–88	72.3 (27) 59–90	72.8 (12) 64–86	75.8 (25) 50–87	66.6 (10) 60–75	68.4 (8) 61.6–75	60.6 (10) 38–77
HF	21.5 (2) 21–22	20.2 (21) 18–22	20.9 (27) 17–23	17.9 (12) 16–20	19.2 (25) 17–23	21.2 (10) 20–22.5	21.2 (8) 20–22	16.6 (10) 15–17
E	17 (2) 16–18	17 (21) 14–19	16.8 (27) 15–19	15.7 (12) 14–18	15.4 (25) 14–17	17 (10) 13.5–21	16.5 (8) 14–18	14.2 (10) 13–16
W	30 (2) 25–35	28.2 (21) 19–40	29.9 (27) 20–46.9	30.5 (12) 21–42	35.8 (25) 25–51	25.3 (8) 14.6–31	25.3 (8) 14.6–31	14.5 (10) 10–17
SL	26 (3) 24–28	25.5 (21) 23.7–28.2	25 (22) 22.5–27.8	25.0 (5) 24.3–26.3	26.7 (11) 23.7–28.4	24.8 (8) 22.9–26	25.0 (7) 24.2–28.6	22.1 (10) 21–23.5
CI	24.3 (3) 22.8–26.2	23.7 (21) 22.2–26.2	22.9 (24) 20.2–26	23.3 (5) 22.8–24.5	24.8 (11) 22.4–26.9	22.5 (10) 19.7–24.3	23.5 (8) 20.9–26.5	19.9 (10) 18.8–21
BO	6.3 (3) 6.1–6.4	5.8 (21) 5.5–6.2	5.8 (23) 5.3–6.4	6.1 (5) 5.9–6.7	6.1 (11) 5.7–6.3	5.9 (11) 5.6–6.3	6.0 (8) 5.7–6.6	5.1 (10) 4.7–5.5
LD	6.4 (3) 5.9–6.7	6.4 (21) 5.8–7.8	6.2 (26) 5.3–7.2	6.5 (5) 6.4–6.6	6.6 (11) 4.7–7.1	6 (11) 5.2–6.8	6.2 (8) 5.1–7.3	5.3 (10) 5.0–5.8
PB	4.7 (3) 4.5–4.8	4.2 (21) 3.7–4.8	4.5 (24) 3.8–5.2	4.7 (5) 4.4–5.1	5.0 (11) 4.3–5.5	4.7 (11) 4.2–5.3	4.9 (8) 4.2–5.9	3.7 (10) 3.5–4.2
LI	5.9 (3) 5.6–6.4	5.6 (21) 4.9–6.5	5.6 (27) 4.8–6.5	5.6 (5) 5.3–6	5.9 (11) 5.3–6.4	4.8 (11) 4.2–5.4	5.3 (8) 4.6–5.9	4.6 (10) 3.8–5.1
BI	1.8 (3) 1.7–2.0	1.7 (21) 1.5–2.2	1.7 (27) 1.5–2.1	1.8 (5).7–1.9	1.9 (11) 1.6–2.1	1.6 911) 1.4–1.9	1.8 (8) 1.5–2.1	1.5 (10) 1.3–1.7
LM	4.1 (3) 3.9–4.4	4.0 (21) 3.8–4.2	4.1 (27) 3.8–4.4	4.1 (5) 4.0–4.3	4.1 (11) 3.8–4.4	4.2 (11) 3.8–4.5	4.3 (8) 4.1–4.6	3.4 (10) 3.1–3.9
M1	1.3 (3) 1.2–1.5	1.2 (21) 1.1–1.4	1.2 (27) 1.1–1.3	1.3 (5) 1.3–1.4	1.3 (11) 1.2–1.4	1.3 (11) 1.2–1.4	1.3(8) 1.2–1.4	1.0 (10) 0.9–1.1
OL	9.1 (3) 8.8–9.5	9.4 (21) 8.8–10.3	9.1 (27) 7.8–10.4	8.8 (5) 8.6–8.9	9.5 (11) 8.8–10.0	8.1 (11) 7.5–9.5	9.1 (8) 8.4–10.3	8 (10) 7.1–8.3
IB	4.3 (3) 4.1–4.6	4.2 (21) 3.83–4.7	4.2 (27) 3.8–4.0	4.4 (5) 4.3–4.5	4.6 (11) 4.3–5.0	4.2 (11) 3.8–4.5	4.3 (8) 3.8–4.6	3.7 (10) 4.1–3.4
ZB	14 (3) 13.5–14.7	13.3 (21) 12.5–14.0	13.3 (27) 12.3–14.4	13.2 (5) 12.7–14.3	14.2 (11) 12.6–14.7	13.4 (11) 11.8–14.2	13.8 (8) 12.6–15.3	11.5 (10) 10.6–12.2
BB	11.3 (3) 11.2–11.5	10.8 (21) 10.2–11.4	11.1 (27) 10.4–11.8	11.1 (5) 10.6–11.6	11.5 (10) 11.1–12.1	10.7 (10) 9.9–11.1	10.9 (8) 10.5–11.2	9.8 (10) 9.5–10.4
LR	9.4 (3) 8.8–10.3	9.1 (21) 8.2–10.4	-	9.3 (5) 8.8–10.3	9.8 (11) 8.2–10.7	8.8 (9) 8.2–9.6	9.1(7) 8.1–10.4	7.6 (10) 7.0–8.5
BR	4.9 (3) 4.6–5.5	4.8 (21) 4.4–5.4	-	5 (5) 4.6–5.4	5.2 (11) 4.8–5.6	4.6 (11) 4–4.9	4.6(8) 4.3–5.0	4.2 (10) 3.9–4.5