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1

Parasitism underground: lice (Insecta: Phthiraptera) from Ctenomys talarum (Rodentia: Ctenomyidae) along its coastal distribution in Argentina

100%
Martino N. S., Romero M. D., Malizia A. I.
Acta Parasitologica
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2015
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tom 60
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nr 1
2

Food-handling and feces reingestion in Ctenomys pearsoni [Rodentia, Ctenomyidae]

100%
Altuna C. A., Bacigalupe L. D., Corte S.
Acta Theriologica
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1998
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tom 43
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nr 4
The food-handling and reingestive behaviour of feces by Ctenomys pearsoni Lessa and Langguth, 1983, was studied in the laboratory. All animals studied handle grasses with dexterity with one or both forepaws, and vigorously shaked it up and down before ingestion. Reingestion of feces occur frequently during resting periods and between feeding bouts. While performing both behaviours, C. pearsoni adopt a posture that not increase its height, what could be considered as and adaptation to the burrow space. Some convergences and divergences in the patterns of food-handling and reingestion of feces between Ctenomys and other subterranean rodents genera were remarked. We propose that the food-handling pattern is related to the cleaning of food; while the reingestion pattern might be related to water economy and to recover some particular nutrients.
3

Ctenomys lami: The highest chromosome variability in Ctenomys [Rodentia, Ctenomyidae] due to a centric fusion-fission and pericentric inversion system

100%
Freitas T. R. O.
Acta Theriologica
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2007
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tom 52
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nr 2
Ctenomys lami Freitas, 2001 is an endemic species of rodent inhabiting the Coastal Plain of southern Brazil, along a narrow line of old dunes formed in the Pleistocene. This species has five different diploid numbers (2n=54, 55a, 55b, 56a, 56b, 57 and 58) and ten different autosomal fundamental numbers (FNa=74, 75, 76, 77, 78, 79, 80, 81, 82, and 84). In a sample of 102 specimens, the combined 2n and FNa formed 26 different karyotypes. The diploid number variation was due to Robertsonian rearrangements that occur in pairs 1 and 2, and the variation of NFas was due to pericentric inversions. The distribution of diploid number variation along the 78 km line of collection sites reveals four population blocks: block A with 2n=54, 55a, and 56a; block B with 2n=57 and 58; block C with 2n=54 and 55a; and block D with 2n=56b and 55b. The inversion system lacks geographic structure with a random distribution of inversions along the population blocks. A very narrow hybrid zone is hypothesized between blocks A and B. Blocks B and C are separated by a geographic barrier, and another hybrid zone is found between blocks C and D. My findings suggest that this species is undergoing a process of speciation due to geographic isolation.
4

Diet of a Piedmont population of Ctenomys mendocinus [Rodentia, Ctenomyidae]: seasonal patterns and variations according sex and relative age

80%
Puig S., Rosi M. I., Cona M. I., Roig V. G., Monge S. A.
Acta Theriologica
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1999
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tom 44
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nr 1
Dietary composition was determined seasonally in males and females of Ctenomys mendocinus Philippi, 1869 from the Andean Piedmont (Mendoza, Argentina) during the reproductive and non-reproductive period. Reproductive condition and relative age of each animal was determined. Stomach contents were individually analyzed with the microhistological technique, Dietary generalism is supported by the high propor­tion of available genera eaten, but the intensity and continuity of use suggested specialization on grasses. Prédation risk induces minimization of the exposure time out of the burrow, and could justify the specialization in grasses, considering that other rodents showed lower harvest and handling times for grasses than for shrubs. Males had a more varied diet than females in winter, and the opposite occurred in spring. Since males have been found to dig longer burrow systems than females in winter, searching for mates might cause males to intersect a higher number of food items during that season. Higher energetic and nutritional requirements associated with pregnancy and nursing may lead to the inclusion of more food items in the spring diet of females, and their higher specialization on grasses. Dietary similarities between immature and mature individuals suggested that age did not affect selection of diet items. Seasonal variation in dietary diversity suggested a foraging strategy adaptive to environmental seasonal variations and to the subterranean life style.
5

Heterogeneity of heterochromatin in six species of Ctenomys [Rodentia: Octodontoidea: Ctenomyidae] from Argentina revealed by a combined analysis of C- and RE-banding

70%
Ipucha M. C., Gimenez M. D., Bidau C. J.
Acta Theriologica
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2008
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tom 53
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nr 1
Exceptional chromosomal variability makesCtenomys an excellent model for evolutionary cytogenetic analysis. Six species belonging to three evolutionary lineages were studied by means of restriction endonuclease and C-chromosome banding. The resulting banding patterns were used for comparative analysis of heterochromatin distribution on chromosomes. This combined analysis allowed intra- and inter-specific heterochromatin variability to be detected, groups of species belonging to different lineages to be characterized, and phylogenetic relationships hypothesized from other data to be supported. The “ancestral group”,Ctenomys pundti andC. talarum, share three types of heterochromatin, the most abundant of which was also found in C. aff.C. opimus, suggesting that the latter species also belongs to the “ancestral group”. Additionally, within the subspeciesC. t. talarum, putative chromosomal rearrangements distinguishing two of the three chromosomal races were identified. Two species belong to an “eastern lineage”,C. osvaldoreigi andC. rosendopascuali, and share only one type of heterochromatin homogeneously distributed across their karyotypes.C. latro, the only analyzed species from the “chacoan” lineage, showed three types of heterochromatin, one of them being that which characterizes the “eastern lineage”.C. aff.C. opimus, because of its low heterochromatin content, is the most primitive karyotype of the genus yet described. The heterochromatin variability showed by these species, reflecting the evolutionary divergence toward different heterochromatin types, may have diverged since the origin of the genus. Heterochromatin amplification is proposed as a trend withinCtenomys, occurring independently of chromosomal change in diploid numbers.
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