This Province includes the southern part of the Coastal Plain physiographic region, south of the Sierra de Tamaulipas and Soto la Marina. But the exact line between this Province and the Tamaulipan Province to the north is difficult to draw. The northern boundary of the Veracruzian Province is the line between the Nearctic and Neotropical regions in eastern México.
Vegetation of most of the Veracruzian Biotic Province is Tropical Deciduous Forest. This Forest is made up of Tabebuia, Ipomea, Bombax, and Conzattia, along with some Ceiba, Bursera, and Psidium.
The mammalia fauna of the Veracruzian Biotic Province is tropical in nature. This is especially true of the bats. Representatives of the tropical genera Micronycteris, Sturnira, Artibeus, Enchistenes, Desmodus, Diphylla, and Molossus have their northern distributional limits in this Province. The non-flying mammals characteristic of the Province in Tamaulipas are: Philander opossum pallidus; Marmosa mexicana; Ateles geoffroyi velerosus; Geomys tropicalis; Oryzomys melanotis rostratus; O. alfaroi huastecae; O. fulvescens engracie (endemic to this Province in Tamaulipas); O. f. fulvescens; Reithrodontomys mexicanus; Peromyscus orchraventer (endemic); Neotoma micropus angustapalata; Eira barbara senex; Felis wiedii oaxacensis; and Mazama americana temama.
BARRIERS AND ROUTES OF MOVEMENT
The distributional patterns and affinities of the mammalian fauna of Tamaulipas suggest possible routes of migration and barriers that limited or controlled movements of the mammals.
Mammals may have reached Tamaulipas by way of a Northern route, a Trans-plateau route, a Montane route, or a Tropical route ([Fig. 3]).
The Northern route permitted species of mammals from the temperate region to the north to enter the Tamaulipan Biotic Province from or via Texas. Several came from the Great Plains, and a few came from the eastern part of the United States. Also, a few mammals that may have originated in the Tamaulipan Province moved northwards. Some of these, according to Dice (1937:267) were Liomys irroratus texensis, Peromyscus leucopus texensis, and Lepus californicus merriami. Other mammals thought to have moved north by this route are Didelphis marsupialis, Dasypus novemcinctus, Oryzomys palustris, Nasua narica, and Tayassu tajacu. Some mammals that passed through Tamaulipas into Texas have extended their geographic ranges far north of Texas.
Mammals that came via the Trans-plateau route (name proposed by Baker, 1956:146) came no farther into Tamaulipas than the Chihuahuan Biotic Province. They encountered the barrier formed by the Sierra Madre Oriental. These mammals were listed in the account of the Chihuahuan Biotic Province.