Cryptonanus agricolai ( Moojen, 1943 )

VOSS, ROBERT S., LUNDE, DARRIN P. & JANSA, SHARON A., 2005, On the Contents of Gracilinanus Gardner and Creighton, 1989, with the Description of a Previously Unrecognized Clade of Small Didelphid Marsupials, American Museum Novitates 3482, pp. 1-35 : 11-14

Cryptonanus agricolai ( Moojen, 1943)

Grymaeomys pusillus: Winge, 1893: 27 (part). A misidentification based on a composite series of ZMUC specimens representing the present species and an unidentified species of Gracilinanus (see below); not pusillus Desmarest, 1804 , a valid species of Thylamys .

IDENTIFICATION AND DISTRIBUTION: Specimens that we refer to this taxon are from the Caatinga and Cerrado biomes of east­central Brazil. By comparison with other forms of Cryptonanus , most specimens of C. agricolai have self­whitish ventral fur (the ventral fur is gray­based buffy in guahybae ), small molars (4.9–5.4 mm versus. 5.4 mm in most specimens of unduaviensis ), and a complete anterior cingulum on M3 (versus M3 anterior cingulum usually incomplete in chacoensis ). The unique exception to this provisional diagnosis is BMNH 93.4.16.4, a Reinhardt specimen from Lagoa Santa, which has graybased ventral fur. It is also noteworthy that a larger proportion of examined specimens of C. agricolai exhibit a secondary foramen ovale than do our samples of other species (table 3). We have not seen any fluid­preserved parous adult females, so the mammary complement of this species is unknown. External and craniodental measurements of representative specimens examined are provided in table 5.

REMARKS: This species was synonymized with Gracilinanus emiliae by Gardner and Creighton (1989), but Voss et al. (2001: 29) disagreed and suggested that the type of agricolai needed to be reexamined to determine its true relationships. Although we have not seen the holotype, we were able to borrow the paratype (MNRJ 1494), which agrees in all relevant details with Moojen’s (1943) description and illustration.

Carvalho et al. (2002) described the chromosomes of this species (which they identi­

TABLE 4 Morphological Comparisons among Cryptonanus and Other Closely Related Didelphine Taxaa

TABLE 4 (Continued)

TABLE 5 External and Craniodental Measurements (mm) and Weights (g) of Cryptonanus agricolai (All referred specimens are from Brazil.)

fied as Gracilinanus emiliae ) based on 13 specimens from Goiás. According to their cytogenetic analysis, the karyotype consists of 14 diploid chromosomes, of which 6 pairs are biarmed autosomes (2 n 5 14, FN 5 24); the X chromosome is metacentric or acrocentric (polymorphism in this trait was not­ ed), the Y is acrocentric, and the nucleolar organizing region is on the short arm of chromosome 6 .

The Lagoa Santa material that Winge (1893) reported as Grymaeomys pusillus is composite. Whereas three ZMUC specimens so identified in Winge’s distinctive handwriting (ZMUC 149, 151, 160) are Cryptonanus agricolai , another (ZMUC 225) is an unidentified species of Gracilinanus . 6 Winge’s published illustration (1893: pl. II, fig. 4), however, clearly shows the principal diag­

6 ZMUC 225, a skin and partial skull from Lund’s original collection (number L.16), is either Gracilinanus agilis or G. microtarsus —morphologically similar and occasionally sympatric species whose diagnostic differences were not known to RSV at the time he examined this specimen in Copenhagen. Tate (1933: 191) examined ZMUC 225 and referred it to G. microtarsus , but this identification should be reconfirmed using the criteria suggested by Costa et al. (2003).

nostic traits of Cryptonanus (premolar proportions, absence of maxillary palatal fenestrae, and absence of a secondary foramen ovale). Tate (1933) examined many of the ZMUC specimens listed below and misidentified them as Marmosa agilis agilis .

SPECIMENS EXAMINED: Brazil — Ceará, Crato (MNRJ 1494); Goiás, 20 km NW Colinas do Sul (MNRJ 36305, 36526), Serra Negra region (MNRJ 36215, 36216); Minas Gerais, Lagoa Santa (BMNH 93.4.16.4; ZMUC 149–152, 154, 155, 157, 160).