The central Texas pocket gopher or Llano pocket gopher (''Geomys texensis'') is a species of

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

in the family Geomyidae. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to central

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

Description

The central Texas pocket gopher is very similar in appearance to its close relatives, the

plains pocket gopher The plains pocket gopher (''Geomys bursarius'') is one of 35 species of pocket gophers, so named in reference to their externally located, fur-lined cheek pouches. They are burrowing animals, found in grasslands and agricultural land across the G ...

and

Knox Jones's pocket gopher Knox Jones's pocket gopher (''Geomys knoxjonesi'') is a species of pocket gopher found in Texas and New Mexico. This species is named for Dr. J. Knox Jones Jr. (1929–1992), a prolific mammalogist at Texas Tech University. It is a relatively s ...

, and the three species can be difficult to distinguish visually. Males average in length, and females ; both sexes have a tail about long. The fur is brownish over most of the body, with a paler, yellowish collar about the throat, and white underparts and feet. The winter coat is darker than the summer one, with the underparts sometimes pale grey in color.

Distribution

Geomys texensis can primarily be found in central Texas. Northern specimens reside in stretches along McCulloch, San Saba, and Lampasas counties, and extend to Zavala, Frio, and Medina counties in the south. The three subspecies of Geomys texensis (llanensis, texensis, and bakeri) are located in several clades over these ranges, and they are typically characterized as being northern or southern-dwelling. Northern specimens G. t. texensis and G. t. llanesis are parapatric in their distribution. That is, their respective ranges do not overlap, however, they are immediately adjacent to each other. The third subspecies, G. t. bakeri, is geographically isolated from the other two subspecies, and can primarily be found in the southern counties of Medina, Uvalde, and Zavala. The significant geographic segregation between the three subspecies has recently been highlighted, as genetic implications associated with habitat range are currently being investigated. Primarily, genetic differences between the northern-dwelling G. t. texensis and G. t. llanesis, and the southern-dwelling G. t. bakeri are being examined.

Morphological Implications

The lack of cranial morphological differentiation between G. texensis and its sibling species have posed problems for scientists attempting to affirm the characteristics unambiguously associated with G. texensis. Conservation of morphological characters, that scientists postulate arose from adaptations to a fossorial lifestyle, is one reason G. texensis and its pocket gopher siblings look alike. Genetic isolation is rarely complemented by morphological evolution. This phenomenon leads to the need for a more comprehensive understanding of the genetic makeup of G. texensis and its siblings.

Genetics

Due to recent major advancements in the field of genetics, DNA sequencing is now a useful method scientists use to characterize and understand organisms. The need for expanded sampling of G. texensis has been recognized as an important goal in differentiating G. texensis from other members of its taxa. This is because there is limited morphological divergence among taxa related to G. texensis. Extensive population sampling is the likely first step scientists will take in order to collect genetic data sets on G. texensis. The development of advanced molecular techniques is what led to the elevation of G. texensis to species status. Mitochondrial cytochrome-b is often used as a template for DNA sequencing, and it has successfully been used to construct phylogenetic relationships between G. texensis and its subspecies. Cytochrome-b has previously been used to reconstruct phylogenetic relationships between rodents, so it is currently a preferred method in regards to genetic analysis. Chromosomal examination of G. texensis and its proximate taxa is another method researchers have utilized in order to better understand what distinguishes G. texensis from other pocket gophers. Distinctions between gophers in this particular model are based on differing diploid number and chromosomal morphology. In particular, the geographic distribution of the northern G. texensis subspecies have 2n=70-72, but with altering morphology. Additionally, the southern-dwelling specimens have 2n=70, 71, 72, or 74.

Biology

As its name implies, the species is found only in central Texas, where it inhabits areas with

loam Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–sil ...

y soils suitable for digging. They are solitary animals, occupying tunnel systems that are typically at least apart. The burrows contain multiple chambers, including food caches and

latrines A latrine is a toilet or an even simpler facility that is used as a toilet within a sanitation system. For example, it can be a communal trench in the earth in a camp to be used as emergency sanitation, a hole in the ground (pit latrine), or m ...

in addition to resting chambers, and vertical corkscrew tunnels to deter predators. They give birth to a litter once each year. One species of

Ischnocera The Ischnocera is a large superfamily of lice. They are mostly parasitic on birds, but including a large family (the Trichodectidae) parasitic on mammals. The genus '' Trichophilopterus'' is also found on mammals (lemurs), but probably belongs ...

n chewing

louse Louse ( : lice) is the common name for any member of the clade Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera has variously been recognized as an order, infraorder, or a parvorder, as a result o ...

, ''Geomydoecus heaneyi'', is only known to live in the fur of central Texas pocket gophers.

Subspecies

Three subspecies have been identified: * ''G. t. texensis'' -

Mason Mason may refer to: Occupations * Mason, brick mason, or bricklayer, a craftsman who lays bricks to construct brickwork, or who lays any combination of stones, bricks, cinder blocks, or similar pieces * Stone mason, a craftsman in the stone-cut ...

McCulloch McCulloch is a Scottish surname. It's a variation of the Northern Irish surname McCullough. It's commonly found in Galloway. Notable people with the surname include: *Alan McCulloch (politician), New Zealand politician *Alan McLeod McCulloch ( ...

, and San Saba counties * ''G. t. bakeri'' -

Medina Medina,, ', "the radiant city"; or , ', (), "the city" officially Al Madinah Al Munawwarah (, , Turkish: Medine-i Münevvere) and also commonly simplified as Madīnah or Madinah (, ), is the Holiest sites in Islam, second-holiest city in Islam, ...

, Uvalde, and Zavala counties * ''G. t. llanensis'' - Gillespie, Kimble and Llano counties

References

{{Taxonbar, from=Q309321

Central Texas Pocket Gopher The central Texas pocket gopher or Llano pocket gopher (''Geomys texensis'') is a species of rodent in the family Geomyidae. It is endemic to central Texas in the United States. Description The central Texas pocket gopher is very similar in ap ...

Mammals of the United States Rodents of North America Fauna of the Great Plains Mammals described in 1895 Least concern biota of the United States Taxonomy articles created by Polbot