Cryptonanus unduaviensis ( Tate, 1931 )

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 : 17-19

Cryptonanus unduaviensis ( Tate, 1931)

Marmosa unduaviensis Tate, 1931: 11 . Original description based on the holotype (by original designation: AMNH 72563 ) and one paratype, both collected at Pitiguaya , Río Unduavi, La Paz, Bolivia.

Marmosa (Thylamys) unduaviensis: Cabrera, 1958: 33 . New name combination.

Thylamys unduaviensis: Reig et al., 1985: 342 . New name combination implied by raising Thylamys (sensu Kirsch and Calaby, 1977) to generic rank.

Gracilinanus agilis: Gardner and Creighton, 1989: 5 (part). New name combination and synonymy based on alleged conspecificity with G. agilis (Burmeister, 1854) .

IDENTIFICATION AND DISTRIBUTION: Specimens that we refer to Cryptonanus unduaviensis are all from eastern Bolivia. These are

TABLE 8 External and Craniodental Measurements (mm) and Weight (g) of Cryptonanus ignitus among the largest specimens of the genus (table 9), with an average molar toothrow length that substantially exceeds than that of any other congeneric species sample (table 10). The anterior cingulum of M3 is narrow but complete (versus usually incomplete in C. chacoensis ), and the ventral fur is either self­colored or indistinctly gray­based (versus distinctly gray­based buffy in C. guahybae ). We have not examined any suitably preserved parous adult females, so the mammary complement of C. unduaviensis is unknown.

The material at hand is somewhat variable in coloration, possibly due to geographic variation, individual variation, and/or preservational artifacts that we are currently unable to distinguish as such. The dorsal fur is dull grayish­brown in the holotype and most oth­ er specimens, but a few skins collected by the Middle American Research Unit (MARU) of the National Institutes of Health (perhaps treated with borax or some other preservative) are distinctly reddish (e.g., FMNH 114658). The ventral pelage is indistinctly gray­based in some specimens, but most have self­colored whitish venters; the MARU­collected specimens mentioned earlier, however, have self­orange ventral fur. No craniodental variation appears to be correlated with any of this pelage variation, which does not appear to be taxonomically significant.

REMARKS: The series of Bolivian specimens from San Joaquín that Hershkovitz (1992: 35–36) referred to Gracilinanus agilis is composite. Among the 30 specimens that we were able to locate in the FMNH, four were Cryptonanus unduaviensis and 26 were G. agilis . Although some of the phenotypic variation that Hershkovitz remarked in the San Joaquín series is doubtless attributable to this heterogeneity, our taxonomic assignments do not agree in all cases with his observations about morphological anomalies in this material. 9

Of the seven specimens identified as ‘‘ Gracilinanus agilis unduaviensis ’’ that Anderson (1997) reported from Bolivia, two (AMNH 72563, 72565) represent Tate’s (1931) type series. Of the remainder, we were only able to examine three (UMMZ 155829, 156006, 156007), all of which are examples of Marmosops noctivagus as previously explained elsewhere ( Voss et al., 2004b). Instead, most of the Bolivian material that we refer to Cryptonanus unduaviensis was identified by Anderson (1997) as Gracilinanus agilis buenavistae (e.g., AMNH 209150–209156, 260031, 260032, 262401).

9 Among other sources of confusion in attempting to reconcile our identifications with Hershkovitz’s (1992) text, he referred to 39 specimens of Gracilinanus agilis from San Joaquín in a discussion of bullar variation (p. 23), but subsequently recorded having examined only 32 specimens from that locality (p. 36). We were able to find only 30 specimens from San Joaquín with this identification in the FMNH, of which the following are referrable to G. agilis in our usage of that binomen: 114652, 114654–114657, 114659–114663, 114666, 114668, 114669, 114671–114680, and 114682–114684. Consistent with our taxonomic assignments, Hershkovitz (p. 23) reported the absence of anteromedial bullar processes in FMNH 114658 (a specimen of Cryptonanus unduaviensis ), but he also stated that these processes were absent in 114654 (a specimen of G. agilis ). Because all of the G. agilis that we examined from San Joaquín have anteromedial bullar processes, the latter specimen may have been 114664 ( C. unduaviensis ). Hershkovitz’s other remarks (p. 35) about individual differences in size, pelage color, premolar proportions, and other characters within the San Joaquín series are impossible to associate with particular specimens, but it is clear that he did not distinguish intraspecific from higher­taxonomic variation in this material.

TABLE 9 External and Craniodental Measurements (mm) and Weights (g) of Cryptonanus unduaviensis (All tabulated measurements are from Bolivian specimens.)

SPECIMENS EXAMINED: Bolivia — Beni, Boca del Río Baures (AMNH 209152, 209153), Campo Alegre (MSB 70752), Magdalena (USNM 460732), Pampa de Meio (AMNH 209150, 209151, 209154–209156), Puerto Caballo (AMNH 210396), San Joaquín (FMNH 114658, 114664, 114665, 114667; USNM 364718); La Paz, Pitiguaya (AMNH 72563, 72565); Pando, Independencia (AMNH 262401, MSB 57000); Santa Cruz, 2 km S Caranda (MSB 58508), El Refugio (IGP 157), Estancia Cachuela Esperanza (AMNH 260031), Santiago de Chiquitos (AMNH 260032).