taxonID	type	description	language	source
03E2EF372720FF96FE54F9F6982AFA92.taxon	materials_examined	TYPE SPECIES: Monodelphis adusta (Thomas, 1897). CONTENTS: adusta Thomas, 1897 (including melanops Goldman, 1912); peruviana Osgood, 1913; osgoodi Doutt, 1938; kunsi Pine, 1975; reigi Lew and Pérez-Hernández, 2004; ronaldi Solari, 2004; handleyi Solari, 2007; and pinocchio Pavan, 2015.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372720FF96FE54F9F6982AFA92.taxon	diagnosis	DIAGNOSIS: Dorsal body pelage unpatterned; ventral pelage uniformly colored or with self-whitish median markings. 5 Mammae 2 – 0 – 2 = 4 (e. g., in M. peruviana; AMNH 264562), 3 – 0 – 3 = 6 (e. g., in M. adusta; AMNH 202650), or 3 – 1 – 3 = 7 (e. g., in M. pinocchio; MZUSP MTR 15815), all abdominal-inguinal. Thenar and first interdigital pad of pes separate, not fused; hypothenar pad of pes present (but unknown for M. reigi, M. peruviana, and M. ronaldi). Body pelage extends onto tail farther ventrally than dorsally; tail scales arranged in annular or spiral series. Infraorbital foramen dorsal to M 1; frontal process of jugal absent or indistinct; parietal usually (> 90 % of examined specimens) not in contact with mastoid; length of incisive foramina variable; length of maxillopalatine fenestra variable; sphenorbital fissure small (basisphenoid laterally concealed); infratemporal crest of alisphenoid distinct or indistinct; secondary foramen ovale usually absent 6; tympanic wing of alisphenoid small; tip of anterior process of malleus exposed on external bullar surface between ectotympanic and alisphenoid; rostral tympanic process of petrosal narrow and triangular, not concealing fenestra cochleae in ventral view; stapes columelliform, imperforate or microperforate; subsquamosal foramen large. Anterior cingulids of m 2 and m 3 narrow; entoconids of m 1 – m 3 very small, indistinct; dp 3 small, with incomplete trigonid and indistinct anterior cingulid in some species (e. g., M. adusta, M. reigi), but dp 3 large, with complete trigonid and distinct anterior cingulid in other species (e. g., M. handleyi; the morphology of dp 3 is unknown for M. peruviana, M. osgoodi, M. ronaldi, M. pinocchio, and M. kunsi).	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372720FF96FE54F9F6982AFA92.taxon	discussion	COMPARISONS: Members of the subgenus Mygalodelphys differ from currently recognized species in other subgenera of Monodelphis by several unique external and craniodental traits, including: (1) soπ body pelage that extends onto the tail farther ventrally than dorsally; (2) frontal process of jugal absent or indistinct; (3) parietal-mastoid contact absent; (4) a small sphenorbital fissure that does not expose the basisphenoid to lateral view; (5) narrow lower molar anterior cingulids; and (6) indistinct entoconids on m 1 – m 3. Self-whitish midventral pelage markings are also unique to Mygalodelphys, although they are oπen polymorphic and are not present in all member species. Among other diagnostic comparisons (table 2), Mygalodelphys additionally differs from Pyrodelphys by its unpatterned dorsal pelage, separate thenar and first interdigital pads on the hind foot, small alisphenoid tympanic wing, exposure of the anterior process of the malleus on the external surface of the bulla, narrow-triangular rostral tympanic process of the petrosal, and a large subsquamosal foramen. Mygalodelphys additionally differs from the usual morphology seen in the nominotypical subgenus by possessing a distinct hypothenar pad on the hindfoot, an infraorbital foramen that is dorsal to M 1, and a columelliform stapes. Mygalodelphys additionally differs from Microdelphys by its consistently unpatterned dorsal pelage, small alisphenoid tympanic wing, exposure of the anterior process of the malleus on the external surface of the bulla, and narrow-triangular rostral tympanic process of the petrosal. Mygalodelphys additionally differs from Monodelphiops by its unpatterned dorsal pelage, lack of pectoral mammae, and possession of a hypothenar pad of the hind foot.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372720FF96FE54F9F6982AFA92.taxon	etymology	ETYMOLOGY: From mygale, ancient Greek for “ shrew, ” which members of this clade strikingly resemble in general aspect.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372720FF96FE54F9F6982AFA92.taxon	discussion	REMARKS: Mygalodelphys corresponds to “ clade E ” or the “ Adusta Group ” (Pavan et al., 2014; Pavan et al., 2016), which was recovered with consistently robust support in our previous phylogenetic analyses. Although taxon-dense phylogenetic analyses incorporating morphological characters have yet to be done, it seems likely that several features unique to this subgenus (e. g., body pelage extending onto the tail farther ventrally than dorsally; frontal process of the jugal absent or indistinct; no parietal-mastoid contact; narrow lower molar anterior cingulids) will eventually be found to optimize as subgeneric synapomorphies. Phylogenetic analyses based on mitochondrial and nuclear gene sequences (Pavan et al., 2014; Vilela et al., 2015; Pavan et al., 2016) have consistently recovered a basal dichotomy among the species that we refer to Mygalodelphys: one clade including Monodelphis kunsi and M. pinocchio (M. “ species 1 ” of Pavan et al., 2014; Vilela et al., 2015), and another including M. adusta, M. reigi, M. peruviana, M. osgoodi, M. handleyi, and a still-undescribed form (M. “ species 2 ”). Although these clades are robustly supported by sequence data, morphological data does not support their formal taxonomic recognition. Despite being sister taxa, M. pinocchio and M. kunsi are externally and cranially dissimilar (Pavan, 2015), and we are not aware of any phenotypic trait shared by these two species that consistently distinguish them from the remaining species of Mygalodelphys. Although Monodelphis ronaldi has not been included in any phylogenetic analysis to date, we allocate this species to the subgenus Mygalodelphys based on its close phenetic similarity to M. handleyi (previously noted by Solari, 2007) and to its shared possession of morphological traits that seem likely to optimize as subgeneric synapomorphies, including (1) lack of a distinct frontal process of the jugal, (2) a small sphenorbital fissure within which the basisphenoid is not laterally exposed, (3) lack of parietal-mastoid contact, and (4) narrow anterior cingulids on m 2 and m 3. Including M. ronaldi in future phylogenetic analyses will effectively test the hypothesis that it is a member of Mygalodelphys.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372720FF96FE54F9F6982AFA92.taxon	biology_ecology	NOTES ON DISTRIBUTION AND SYMPATRY: Species of the subgenus Mygalodelphys are known from eastern Panama; the humid tropical and subtropical Andes (to ca. 3000 m) of Colombia, Ecuador, Peru, and Bolivia; the Guiana Highlands of southern Venezuela and western Guyana; western and southeastern Amazonia 7; the Atlantic Forest of southeastern Brazil; the Cerrado landscapes of central Brazil; and the Cerrado, Chaco, and adjacent dry-forested biomes of Bolivia, Paraguay, and northeastern Argentina (table 3). Species of Mygalodelphys are sympatric with Pyrodelphys in southwestern and southeastern Amazonia (e. g., in the lower Urubamba region of eastern Peru; Solari et al., 2001), with species of the subgenus Monodelphis in Amazonia and the Cerrado (e. g., at Bosque Mbaracayú in eastern Paraguay; de la Sancha et al., 2007), with species of the subgenus Microdelphys in the Andes and the Atlantic Forest (e. g., at Riacho Grande, São Paulo, southeastern Brazil; Pavan, 2015), and with species of Monodelphiops in the Atlantic Forest (e. g., at Parque Nacional do Itatiaia, southeastern Brazil; Pavan, 2015). Given this wide distribution and extensive sympatry, the absence of Mygalodelphys throughout most of northeastern Amazonia (north of the Amazon and east of the Rio Negro), where only species of the nominotypical subgenus are known to occur in lowland habitats, is noteworthy. It is also worth noting that Mygalodelphys is the only subgenus known to occur in the northern Andes (north of the Huancabamba Deflection), and in northwestern Amazonia (north of the upper Amazon and west of the Rio Negro). Whether historical or ecological factors account for such distributional phenomena is unknown.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372727FF9BFE45FA7E9832FEE9.taxon	materials_examined	TYPE SPECIES: Monodelphis emiliae (Thomas, 1912). CONTENTS: emiliae Thomas, 1912.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372727FF9BFE45FA7E9832FEE9.taxon	diagnosis	DIAGNOSIS: Dorsal body pelage with grayish midbody contrasting with reddish head and rump (fig. 14 A); ventral pelage uniformly colored (without self-whitish median markings), yellowish or orangish on museum skins, but much brighter in life (fig. 14 B). Mammae 2 – 1 – 2 = 5 (MZUSP 35064), 3 – 1 – 3 = 7 (MPEG JUR 79), or 4 – 1 – 4 = 9 (MPEG 39106, 39182, 42955), all abdominal-inguinal. Thenar and first interdigital pad of pes usually fused or in contact; hypothenar pad of pes usually present. 8 Body pelage extends onto tail farther dorsally than ventrally, or to about the same extent dorsally and ventrally; tail scales arranged in annular series. Infraorbital foramen dorsal to M 1; frontal process of jugal present but rounded, not distinctly angular; parietal usually (ca. 80 % of examined specimens) in contact with mastoid; incisive foramina usually short; maxillopalatine fenestrae short; sphenorbital fissure large, exposing basisphenoid in lateral view; infratemporal crest of alisphenoid distinct; secondary foramen ovale present or absent; tympanic wing of alisphenoid large; tip of anterior process of malleus not exposed on external bullar surface; rostral tympanic process of petrosal broad and rounded, concealing fenestra cochleae in ventral view; stapes columelliform, imperforate or microperforate; subsquamosal foramen small. Anterior cingulids of m 2 and m 3 broad; entoconids of m 1 – m 3 distinct; dp 3 small, with incomplete trigonid and indistinct anterior cingulid. COMPARISONS: Pyrodelphys is uniquely distinguished from other subgenera of Monodelphis by fusion or contact between the thenar and first interdigital pads of the hind foot (the thenar and first interdigital are separate in members of other subgenera) and by having a small subsquamosal foramen (the subsquamosal foramen is distinctly larger in members of other subgenera.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372727FF9BFE45FA7E9832FEE9.taxon	discussion	Among other diagnostic comparisons (table 2), Pyrodelphys is additionally distinguished from the subgenus Monodelphis by having a reddish head and rump separated by a grayish midbody, an infraorbital foramen dorsal to M 1, large alisphenoid tympanic wing, unexposed tip of the anterior process of the malleus, broadly rounded rostral tympanic process of the petrosal, columelliform stapes, and smaller dp 3. Pyrodelphys is additionally distinguished from Microdelphys by lacking dorsal stripes in all age-sex classes, by lacking a distinctly angular frontal process of the jugal, and by having a distinct infratemporal crest of the alisphenoid. Pyrodelphys is also distinguished from Monodelphiops by its dorsal pelage pattern, by lacking pectoral mammae, and by having tail scales in annular series, a large alisphenoid tympanic wing, and a broadly rounded rostral tympanic process of the petrosal. Diagnostic comparisons between Pyrodelphys and Mygalodelphys have already been provided (see above).	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372727FF9BFE45FA7E9832FEE9.taxon	etymology	ETYMOLOGY: From pyr, ancient Greek for “ fire, ” in reference to the flame-colored underparts of living and freshly dead specimens of this clade (fig. 14 B).	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372727FF9BFE45FA7E9832FEE9.taxon	discussion	REMARKS: This taxon is widely divergent from other clades in the genus Monodelphis and appears to represent an ancient lineage with no close extant relatives (Pavan et al., 2014; Pavan et al., 2016). NOTES ON DISTRIBUTION AND SYMPATRY: Monodelphis (Pyrodelphys) emiliae is known from southwestern and southeastern Amazonia (table 3), where it ranges from near the base of the Andes in Peru and Bolivia to eastern Pará, Brazil. Based on geographic range overlap and published reports of cooccurring species (e. g., in the lower Urubamba region of eastern Peru; Solari et al., 2001), Pyrodelphys may occur sympatrically with species of the subgenera Mygalodelphys and / or Monodelphis throughout its geographic range.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372727FF9BFE45FA7E9832FEE9.taxon	discussion	Solari et al., 2001), Pyrodelphys may occur sympatrically with species of the subgenera Mygalodelphys and / or Monodelphis throughout its geographic range.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372729FF9FFE08FDA09A87FCB3.taxon	materials_examined	TYPE SPECIES: Monodelphis tristriata (Illiger, 1815), an objective junior synonym of M. americana (Müller, 1776), by subsequent designation (Thomas, 1888 b). CONTENTS: americana Müller, 1776 (including brasiliensis Erxleben, 1777; brasiliensis Daudin in Lacépède, 1802; rubida Thomas, 1899; trilineata Lund, 1840; tristriata Illiger, 1815; and umbristriata Miranda-Ribeiro, 1936); iheringi Thomas, 1888 a; scalops Thomas, 1888 a (including theresa Thomas, 1921); and gardneri Solari et al., 2012.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372729FF9FFE08FDA09A87FCB3.taxon	diagnosis	DIAGNOSIS: Dorsal body pelage usually marked with dark longitudinal stripes (but uniformly reddish in mature males of M. americana, and with grayish midbody contrasting with reddish head and rump in mature males of M. scalops); ventral pelage uniformly colored, without self-whitish median markings. Mammae 4 – 1 – 4 = 9 to 8 – 1 – 8 = 17, all abdominalinguinal or abdominal-inguinal and pectoral. Thenar and first interdigital pads of hind foot separate; hypothenar pad of hind foot present or absent. Body pelage extends onto tail to about the same extent dorsally and ventrally; tail scales arranged in annular series. Infraorbital foramen usually dorsal to M 1; frontal process of jugal well-developed and distinctly angular; parietal in contact with mastoid; incisive foramina long; maxillopalatine fenestra long; sphenorbital fissure large, basisphenoid laterally exposed; infratemporal crest of alisphenoid indistinct; secondary foramen ovale present or absent; tympanic wing of alisphenoid large; tip of anterior process of malleus not exposed on external surface of bulla; rostral tympanic process of petrosal broad and rounded, concealing fenestra cochleae in ventral view; stapes columelliform, imperforate or microperforate; subsquamosal foramen large. Anterior cingulids of m 2 and m 3 broad; entoconids of m 1 – m 3 distinct; dp 3 small and incompletely molariform (with bicuspid trigonid and indistinct anterior cingulid). COMPARISONS: A dorsal pelage that includes three dark longitudinal stripes is unique to Microdelphys and is present in all member species, although it is lost ontogenetically in adult males of M. americana and M. scalops. Another feature that distinguishes Microdelphys from all other congeners is a well-developed and distinctly angular frontal process of the jugal.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372729FF9FFE08FDA09A87FCB3.taxon	description	Microdelphys additionally differs from Monodelphiops by having caudal scales in annular series, longer incisive foramina and maxillopalatine fenestrae, an indistinct infratemporal crest of the alisphenoid, a large alisphenoid tympanic wing, and a broadly rounded rostral tympanic process that conceals the fenestra cochleae in ventral view. Comparisons of Microdelphys with other subgenera of Monodelphis have already been provided (see above).	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF372729FF9FFE08FDA09A87FCB3.taxon	discussion	REMARKS: As recognized in this report, Microdelphys includes “ Clade C ” and “ Clade D ” as recovered by the molecular analyses of Pavan et al. (2014). Although the sister-group relationship between clades C and D was not recovered by phylogenetic analyses based on mitochondrial sequence data (e. g., by Solari, 2010; Pavan et al., 2014; Vilela et al., 2015), compelling support for this relationship is provided by Bayesian analyses of multigene datasets (e. g., Pavan et al., 2016), and by the three-striped dorsal pelage pattern uniquely shared by juvenile and female specimens of all included species. An alternative nomenclatural solution would be to restrict Microdelphys to “ Clade D ” and to name a new subgenus for Monodelphis scalops (“ Clade C ”), but this seems unnecessary and would effectively discard important information about shared ancestry. NOTES ON DISTRIBUTION AND SYMPATRY: Species of Microdelphys occur in forested areas of easternmost Para, in the Brazilian Atlantic Forest, in northeastern Argentina (Misiones), in some gallery forests of central and northeastern Brazil, and in the central Andes of Peru (Solari et al., 2012; Pavan et al., 2014) (table 3). Microdelphys is broadly sympatric with Monodelphiops in the southern Atlantic Forest, where these taxa have been collected together at several localities (Pavan, 2015), and it also occurs sympatrically with species of Mygalodelphys and Monodelphis (see previous accounts).	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF37272EFF9EFE08FC5F9A0BFA6C.taxon	materials_examined	TYPE SPECIES: Monodelphis sorex (Hensel, 1872), a subjective junior synonym of Monodelphis dimidiata (Wagner, 1847), by original designation. SYNONYMS: Minuania Cabrera, 1919.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF37272EFF9EFE08FC5F9A0BFA6C.taxon	description	CONTENTS: dimidiata Wagner, 1847 (including fosteri Thomas, 1924; henseli Thomas, 1888 a; itatiayae Miranda-Ribeiro, 1936; lundi Matschie, 1916; paulensis Vieira, 1950; and sorex Hensel, 1872); and unistriata Wagner, 1842.	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF37272EFF9EFE08FC5F9A0BFA6C.taxon	diagnosis	DIAGNOSIS: (Asterisks in this section indicate traits exhibited by Monodelphis dimidiata that have yet to be confirmed for M. unistriata.) Dorsal body pelage grayish middorsally, with (M. unistriata) or without (M. dimidiata) a single dark longitudinal stripe, contrasting with clear yellowish, orange, or reddish flanks; ventral pelage uniformly colored (yellowish, orangish, or reddish), without self-whitish markings. Mammae 6 – 5 – 6 = 17 to 11 – 5 – 11 = 27 (Thomas, 1888 b: 361), including abdominal-inguinal and pectoral teats. * Thenar and first interdigital pads of hind foot separate *; hypothenar pad of hind foot absent. * Body pelage extends onto the tail to about the same extent dorsally and ventrally; tail scales arranged in spiral series. Infraorbital foramen dorsal to P 3 or M 1; frontal process of jugal present but rounded, not distinctly angular *; parietal usually (> 90 % of examined specimens) in contact with mastoid *; incisive foramina short; maxillopalatine fenestrae short; sphenorbital fissure usually large, exposing basisphenoid laterally *; infratemporal crest of alisphenoid distinct *; secondary foramen ovale usually absent (rarely present bilaterally) *; tympanic wing of alisphenoid usually small *; tip of anterior process of the malleus exposed or not on external surface of bulla *; rostral tympanic process of petrosal triangular (not broadly rounded), but sometimes concealing fenestra cochleae ventrally *; stapes columelliform, imperforate or microperforate *; subsquamosal foramen large *. Anterior cingulids of m 2 and m 3 broad; entoconids of m 1 – m 3 distinct; dp 3 small and incompletely molariform, with bicuspid trigonid and indistinct anterior cingulid *. COMPARISONS: Comparisons of Monodelphiops with other subgenera of Monodelphis have already been provided (see above).	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
03E2EF37272EFF9EFE08FC5F9A0BFA6C.taxon	discussion	REMARKS: Molecular sequence data are currently unavailable from Monodelphis unistriata, so inferences about its relationships are necessarily based on morphology. Although Pine et al. (2013) recovered M. unistriata as the sister taxon of M. iheringi based on a combined analysis of morphological characters and cytochrome- b sequences (the latter coded as missing for M. unistriata), the authors themselves stated that the characters sampled for their study were not “ sufficiently informative as to allow refined elucidation of the relationships in this genus ” (Pine et al., 2013: 433), and that additional characters as well as inclusion of other species would be necessary to “ ever more firmly ascertain the relationships of this enigmatic taxon ” (Pine et al., 2013: 435). They also noted multiple morphological similarities between M. unistriata and M. dimidiata, suggesting that M. unistriata could be more closely related to M. dimidiata than to any other species (Pine et al., 2013: 432). Among several possible explanations for such anomalous results, M. unistriata is known from just two specimens, one consisting only of a skin and the other of a skin and part of the skull (Pine et al., 2013: fig. 2), so information is missing for many morphological characters, including those of the posterior braincase, zygomatic arches, and ear region. We hypothesize that M. unistriata and M. dimidiata are sister taxa based on shared attributes that seem likely to optimize as synapomorphies in future phylogenetic analyses. Such attributes include: a dorsal body pelage with a grizzled middorsum contrasting with clear yellowish, orange, or reddish flanks; large tail scales arranged in spiral series; very short incisive foramina (a striking similarity previously noted by Pine et al., 2013); and short maxillopalatine fenestrae. Of course, this hypothesis needs to be tested using taxon-dense phylogenetic analyses of morphological and molecular data when fresh material of this apparently elusive species become available. NOTES ON DISTRIBUTION AND SYMPATRY: Monodelphiops occurs in southeastern Brazil, eastern Paraguay, Uruguay, and northeastern Argentina (Vilela et al., 2010; Pine et al., 2013) (table 3), where it is sometimes sympatric with Mygalodelphys and Microdelphys (see previous accounts).	en	Pavan, Silvia E., Voss, Robert S. (2016): A Revised Subgeneric Classification of Short-tailed Opossums (Didelphidae: Monodelphis). American Museum Novitates 2016 (3868): 1-44, DOI: 10.1206/3868.1, URL: http://www.bioone.org/doi/10.1206/3868.1
