Zygodontomys brevicauda (Allen & Chapman, 1893)

Moreira, Camila Do Nascimento, Ventura, Karen, Percequillo, Alexandre Reis & Yonenaga-Yassuda, Yatiyo, 2020, A review on the cytogenetics of the tribe Oryzomyini (Rodentia: Cricetidae: Sigmodontinae), with the description of new karyotypes, Zootaxa 4876 (1), pp. 1-111 : 83-84

Zygodontomys brevicauda (= Z. b. microtinus)

The karyotype of 2n = 78 was reported by Tranier (1976) based on a sample from French Guiana ( Table 11), but the author did not describe or illustrate the karyotype. Another karyotype was reported by Mattevi et al. (2002, pp. 36, Fig. 2 ) and Bonvicino et al. (2009). Karyotype: 2n = 86 and FN = 96 to 100. Autosomal complement: two large submetacentric and subtelocentric pairs, four or five medium to small biarmed pairs, and the remaining being acrocentric. Sex chromosomes: X, a large submetacentric; Y, a medium subtelocentric. C-banding metaphases exhibited blocks of constitutive heterochromatin on the pericentromeric region of the majority of the autosomes, being usually absent on the two large autosomal pairs. The short arm of the X and the whole Y chromosomes were heterochromatic. G-banding was also performed. NORs, were localized at the short arms of one medium and one small acrocentric pairs, but in two metaphase plates a third pair, a medium acrocentric, showed a NORs on its long arm.

According to Bonvicino et al. (2009), the Brazilian populations of Zygodontomys presents, at least, three karyotypes reported, indicating that the diversity of this genus was underestimated in Brazil and suggesting the existence of several evolutionary lineages. Molecular phylogenetic analyses recovered three major clades congruent with known karyotypes, indicating the existence of three species, two of which currently undescribed, mentioned by the authors as Zygodontomys sp. 1 and Zygodontomys sp. 2, whose karyotypes were described below. According to Voss (2015), a more comprehensive revisionary work for the genus is still pending.

Figures

FIGURE 2. Distribution of diploid and fundamental number of karyotyped specimens of genus Cerradomys. (□) C. akroai; (■) C. goytaca; (ê) C. langguthi; (r) C. maracajuensis; (▲) C. marinhus; (○) C. scotti; (☆) C. subflavus; (l) C. vivoi.

Tables

TABLE 11. Karyotype data of genus Zygodontomys. Species, diploid (2n) and fundamental (FN) numbers, collection localities, geographic coordinates and reference.

Species	2n	FN	Locality	Geographic Coordinates	Reference
Z. b. brevicauda	84	-	-	-	Kiblisky et al. 1970
	84	116 or 118	Amazonas, Venezuela	03°10’N; 65°33’W	Reig et al. 1990
	84	116 or 118	Anzoategui, Venezuela	-	Reig et al. 1990
	84	116 or 118	Anzoategui, Venezuela	08°55’N; 64°15’W	Reig et al. 1990
	84	116 or 118	Apure, Venezuela	07°55’N; 68°44’W	Reig et al. 1990
	84	116 or 118	Barinas, Venezuela	-	Reig et al. 1990
	84	116 or 118	Bolivar, Venezuela	-	Reig et al. 1990
	84	116 or 118	Bolivar, Venezuela	08°08’N; 63°33’W	Reig et al. 1990
	84	116 or 118	Carabobo, Venezuela	-	Reig et al. 1990
	84	116 or 118	Guarico, Venezuela	08°56’N; 67°26’W	Reig et al. 1990
	84	116 or 118	Portuguesa, Venezuela	09°18’N; 69°27’W	Reig et al. 1990
	84	116 or 118	Portuguesa, Venezuela	09°20’N; 69°06’W	Reig et al. 1990
	84	116 or 118	Sucre, Venezuela	-	Reig et al. 1990
	88	-	-	-	Perez-Zapata et al. 1984
	88	-	Meta, Colombia	04°09’N; 73°37’W	Gardner & Patton 1976
	88	116 or 118	Monagas, Venezuela	09°04’N; 62°05’W	Reig et al. 1990
Z. b. cherriei	82	-	Puntarenas, Costa Rica	09°05’N; 83°05’W	Voss 1991
	82	-	Zulia, Venezuela	09°50’N; 72°52’W	Voss 1991
	82	116	Zulia, Venezuela	09°50’N; 72°52’W	Bonvicino et al. 2003
	84	-	Puntarenas, Costa Rica	09°30’N; 84°19’W	Gardner & Patton 1976
	84	-	Zulia, Venezuela	09°50’N; 72°52’W	Voss 1991
Z. b. microtinus	78	-	French Guiana	-	Tranier 1976
	86	96 to 100	Amapá, Brazil	01°17’N; 50°48’W	Bonvicino et al. 2009
	86	96 to 100	Amapá, Brazil	01°21’N; 50°56’W	Bonvicino et al. 2009
	86	96 to 100	Roraima, Brazil	04°10’N; 60°30’W	Mattevi et al. 2002; Bonvicino et al. 2009
	86	96 to 100	Guyana, French Guiana	-	Bonvicino et al. 2009
	86	96 to 100	Guyana, French Guiana	05°09’N; 52°39’W	Bonvicino et al. 2009
Zygodontomys sp. 1	84	96 to 98	Amapá, Brazil	01°17’N; 50°48’W	Mattevi et al. 2002
Zygodontomys sp. 2	82	94	Amazonas, Brazil	00°09’N; 63°30’W	Bonvicino et al. 2003; Bonvicino et al. 2009
	82	94	Amazonas, Brazil	00°54’N; 63°26’W	Bonvicino et al. 2003; Bonvicino et al. 2009
	82	94	Roraima, Brazil	01°48’N; 61°07’W	Bonvicino et al. 2009
	82	94	Roraima, Brazil	00°57’N; 61°09’W	Bonvicino et al. 2009