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Analyzing the impact of conflictive dental characters on the phylogeny of octodontoid rodents

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Candela A. M.
Acta Palaeontologica Polonica
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2016
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tom 61
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nr 2
Systematics of fossil octodontoids (Rodentia, Caviomorpha) is in great part based on insights into the knowledge of teeth, making the step of dental characterization certainly relevant for the evolutionary reconstruction of these rodents. Different homology hypotheses were proposed for the same tooth structures, a fact that indicates the importance of knowing on which criteria the dental characters supporting the classifications were based. In this line, I evaluate the step of characterization of certain conflictive molar characters previously used, and their impact on phylogeny of octodontoids. I explore which the criteria followed to propose the hypotheses of correspondences for these characters are in light of the anatomical evidence. Based on the outcome of phylogenetic trees obtained previously, I analyze if the evolutionary transformations are compatible with character states observed in the terminals. New cladistic analyses based on recoded molar characters indicate that, unlike results recently obtained, the unorthodox position of Sallamys, Protadelphomys, and Willidewu as basal ctenomyines is not recovered. The position of Caviocricetus, Acarechimys–Neophanomysas as Octodontinae is not maintained. These results indicate that reanalyses of conflictive dental characters, scrutinizing data matrices, are particularly necessary to evaluate the current controversy on the phylogeny of octodontoids. Lower molar character definition and character states delimitation in octodontoids, being relevant to phylogenetic reconstruction, should be founded on anatomical examination, following explicit criteria of homology. Alternative hypotheses of “primary homology” proposed for the same molar traits in octodontoids indicate that each main group of caviomorphs requires its own anatomical study.
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Koszatniczka Octodon degus [Molina, 1782], Octodontidae [Rodentia] nowym gatunkiem w faunie ssakow Polski

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Ruprecht A. L., Kosciow R., Klys G.
Chrońmy Przyrodę Ojczystą
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2005
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tom 61
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nr 3
69-76
3

Degu Octodon degus [Molina, 1782], Octodontidae [Rodentia] - nowy gatunek w srodkowoeuropejskiej faunie wspolczesnych ssakow

100%
Klys G., Kosciow R., Ruprecht A. L.
Chrońmy Przyrodę Ojczystą
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2004
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tom 60
|
nr 5
104-106
4

Remote sensing variables as predictors of habitat suitability of the viscacha rat (Octomys mimax), a rock-dwelling mammal living in a desert environment

100%
Campos V. E., Gatica G., Bellis L. M.
Acta Theriologica
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2015
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tom 60
|
nr 2
Identifying high-quality habitats across large areas is a central goal in biodiversity conservation. Remotely sensed data provide the opportunity to study different habitat characteristics (e.g., landscape topography, soil, vegetation cover, climatic factors) that are difficult to identify at high spatial and temporal resolution on the basis of field studies. Our goal was to evaluate the applicability of remotely sensed information as a potential tool for modeling habitat suitability of the viscacha rat (Octomys mimax), a rock-dwelling species that lives in a desert ecosystem. We fitted models considering raw indices (i.e., green indices, Brightness Index (BI) and temperature) and their derived texture measures on locations used by and available for the viscacha rat. The habitat preferences identified in our models are consistent with results of field studies of landscape use by the viscacha rat. Rocky habitats were well differentiated by the second-order contrast of BI, instead of BI only, making an important contribution to the global model by capturing the heterogeneity of the substratum. Furthermore, rocky habitats are able to maintain more vegetation than much of the surrounding desert; hence, their availability might be estimated using SATVI (Soil Adjusted Total Vegetation Index) and its derived texture measures: second-order contrast and entropy. This is the first study that evaluates the usefulness of remotely sensed data for predicting and mapping habitat suitability for a small-bodied rock dwelling species in a desert environment. Our results may contribute to conservation efforts focused on these habitat specialist species by using good predictors of habitat quality.
5

A new species of Trichostrongylus [Nematoda, Trichostrongyloidea] parasitizing the subterranean rodent Ctenomys talarum [Rodentia, Octodontidae] from Mar de Cobo, Argentina

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Rossin M. A., Timi J. T., Malizia A. I.
Acta Parasitologica
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2006
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tom 51
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nr 4
A new nematode species, Trichostrongylus duretteae sp. nov., found in the small intestine of Ctenomys talarum from Argentina is described. The new species more closely resembles T. suis lwanitsky, 1930 a parasite of Sus scrofa in the USSR. However, the new species can be distinguished by the morphology of male genital bursa: Rays 6 distant from rays 8 and a larger dorsal ray in relation to the length of rays 2 to 8. The present finding is the first record of the genus Trichostronglyus in rodents of the family Octodontidae.
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The dental evidence on the differentiation of the ctenomyine rodents [Caviomorpha, Octodontidae, Ctenomyinae]

100%
Verzi D. H.
Acta Theriologica
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1999
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tom 44
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nr 3
Primitive species in the differentiation of the subfamily Ctenomyinae are revisited, and, on molar evidence, a new interpretation of the evolutionary pattern of these earliest members of the group is proposed. The octodontid Phtoramys is rejected as possible ancestor, whereas the genus Chasichimys (including Pattersomys), previously included in the family Echimyidae, is transferred to the Octodontidae as a primitive member of the ctenomyine radiation. During the Chasicoan and Huayquerian Ages [Late Miocene), an anagenetic event represented by an increase of hypsodonty in Chasichimys, may have led to the differentiation of the primitive euhypsodont ctenomyines of the genus Xenodontomys. Coeval cladogenetic processes, occurring during the protohypsodont evolutionary stage of the group, would have resulted in the separation of the genus Palaeoctodon from the lineage Chasichimys-Xenodontomys. These ancient representatives of the subfamily would have differentiated in central Argentine pampas. The recognition of such evolutionary events and concordant evidence from other octodontoid rodents suggest temporal differences among the outcroppings of the Cerro Azul Formation in central Argentina.
7

Juvenile vocalizations of Ctenomys talarum [Rodentia: Octodontidae]

100%
Schleich C. E., Busch C.
Acta Theriologica
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2002
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tom 47
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nr 1
We analysed the physical structure and functional interpretation of juvenile vocaliza­tions of Ctenomys talarum Thomas, 1898. Two sounds, one true vocalization (care- -elicitation call) and one mechanical sound (nursing sound) were recorded during the nestling period. Care-elicitation calls were emitted by isolated pups and caused the mother to respond by immediately approaching the pups to take care of them. This maternal response to the care-elicitation calls of C. talarum pups, together with the production of these vocalizations during the first weeks after birth, when pups depend exclusively on their mother to obtain food and maintain their body temperature, give preliminary support for the recent theory that care-elicitation cries are honest adver­tisements of offspring need.
8

Evolutionary relationships of Ctenomys [Rodentia: Octodontidae] from Argentina, based on penis morphology

100%
Balbontin J., Reig S., Moreno S.
Acta Theriologica
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1996
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tom 41
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nr 3
Analyses of qualitative and quantitative variation in bacula and soft parts of the glans penis of 13 species of Ctenomys Blainville, 1926 from Argentina were used to suggest systematic and evolutionary relationships. The 13 species can be divided into spike-bearing {C. australis, C. azarae, C. porteousi, C. rionegrensis, and C. talarum) and spiny bulb-bearing species {C. dorbignyi, C. pearsoni, C. perrensi, C. roigi, Ctenomys sp. from Curuzú Laurel, Ctenomys sp. from M. F. Mantilla, and Ctenomys sp. from San Roque). Ctenomys yolandae is unique because it shows both spikes and spiny bulbs. In addition to spikes and spiny bulbs, some populations of C. pearsoni, C. talarum, and C. yolandae had a new structure, an inner sac of the intromittent sac. The most frequent pattern of occurrence of spikes or spiny bulbs was 1-1 (one at each side of the urethra), an ancestral character state in caviomorphs. Variation in bacular dimensions was limited and differences among species were small, with the exception of C. pearsoni. This species showed a significantly short baculum with a wide base. Sperm and penial morphology suggests that C. talarum is the most plesiomorphic and C. yolandae the most derived species of this group. The pattern of geographic variation among these 13 species rejects the hypothesis of penis morphology contributing to reproductive isolation. Ctenomys pearsoni is the only species with some evidence of reproductive isolation resulting from penis morphology.
9

Redescription and new host record of Paraspidodera uncinata [Rudolphi, 1819] [Nematoda, Aspidoderidae] from the South American subterranean rodent Ctenomys talarum [Rodentia, Octodontidae]

100%
Rossin M. A., Timi J. T., Malizia A. I.
Acta Parasitologica
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2004
|
tom 49
|
nr 4
Paraspidodera uncinata (Rudolphi, 1819) (Nematoda, Aspidoderidae), a parasite of Neotropical caviids and octodontids, is redescribed based on specimens from the caecum and large intestine of the subterranean rodent Ctenomys talarum Thomas, 1898 (Octodontidae). During 2002, a total of 3,899 nematodes was recovered from eighty one specimens of C. talarum (prevalence 93.8%, mean abundance 51.3) from Mar de Cobo, Buenos Aires Province, Argentina (37°58'S, 57°34'W). In spite of the long list of records of P. uncinata published since its original description in 1819, descriptions available in the literature are scattered and incomplete. Therefore, a number of diagnostic morphological and morphometric features that were omitted in previous descriptions of this species, are given. These are: variability in number and position of caudal papillae in males, presence of caudal papillae in females, as well as descriptions and measurements of corpus, bulb, pharynx, lateral alae, deirids, nerve ring, vagina and uterus. Location of labial papillae and the vulva as well as the length of the left and right spicules are also provided.
10

Phylogenetic position of Abalosia and the evolution of the extant Octodontinae [Rodentia, Caviomorpha, Octodontidae]

100%
Verzi D. H.
Acta Theriologica
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2001
|
tom 46
|
nr 3
South American octodontid rodents of the subfamily Octodontinae currently show low species richness but great morphological and chromosomal diversity. This diversity is interpreted alternatively as the remnant of a wider past radiation or as the result of saltational evolution. These hypotheses are discussed in relation to a phylogenetic analysis of the Late Pliocene octodontine Abalosia castellanosi. My results suggest that Abalosia, together with Tympanoctomys and Octomys, is part of a clade of desert specialist propalinal octodontids, which would have differentiated east of the Andes in the emergent semi-deserts of western Argentina. The presence of Abalosia in the coastal region of central Argentina during the Upper Marplatan Age (Late Pliocene) suggests a pulse of expansion of such arid environments, probably coeval with the global climatic deterioration detected around the transition Gauss-Matuyama magnetic ages. The phylogenetic position of A. castellanosi suggests that extinction events affected the clade of the octodontine desert specialists. Accordingly, regardless of how rough or gradual the differentiation of the octodontine's diversity has been, the living representatives seem to be remnants of a wider radiation.
11

Female reproductive responses to photoperiod and male odours in the subterranean rodent Ctenomys talarum

80%
Fanjul M. S., Zenuto R. R.
Acta Theriologica
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2008
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tom 53
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nr 1
The tuco-tucoCtenomys talarum Thomas, 1898 is a solitary subterranean rodent that breeds seasonally in coastal sand-dune grasslands from Argentina. We assessed whether short-day photoperiod determines the onset of reproduction by an increase in female’s receptivity and whether male odour interacts with photoperiod as a cue by producing a greater response in receptivity. Receptivity was measured by an increase in the percentage of vaginal epithelial cells, particularly cornified cells. Females were trapped during their non-reproductive season (summer-long days) and randomly assigned to different day-length experimental groups: constant summer (CS), early winter (EW), and natural (NA) photoperiod. We examined the vaginal epithelium using vaginal smears during the first experimental phase (120 days) to test the effect of photoperiod. In the second experimental phase (15 days), we presented the females with male-soiled shavings to test the effect of photoperiod and male odor.Ctenomys talarum females showed some evidence of reproductive responsiveness to photoperiodic cuing. The proportion of epithelial cells peaked earlier in females when winter day-length was advanced than in females under natural photoperiod. Contrary to that expected, male odours did not stimulate female receptivity. These results suggest that, while photoperiod may participate in regulating reproduction, the integration of other environmental and social factors, as well as the identification of bodily conditions that lead to differences in individual response needs further consideration.
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