Marco Corti’s research while affiliated with Sapienza University of Rome and other places

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Publications (84)


TABLE 3. Summary of the studied allozyme frequencies. 
TABLE 3 . (continued)
Contribution to the systematics and zoogeography of the East–African Acomys spinosissimus Peters 1852 species complex and the description of two new species (Rodentia: Muridae)
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October 2011

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664 Reads

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17 Citations

Zootaxa

Walter Verheyen

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Wim Wendelen

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We revised the taxonomic status of the putative Acomys spinosissimus complex based on the comparative study of specimen collections from Tanzania, Zambia, Zimbabwe, Mozambique, DR Congo and South Africa, by means of analysis of external morphology, craniometry, enzymes, mitochondrial DNA sequences and karyology. Our results confirm that A. spinosissimus represents a complex of species with seemingly non-overlapping distribution ranges. The distribution range of A. spinosissimus appears to be restricted between the Zambesi and Limpopo Rivers, while the reinstated A. selousi (that includes A. transvaalensis) occurs further to the South (i.e. northern limit seemingly just north of the Limpopo River). The investigated populations north of the Zambezi River are morphologically and genetically distinct from A. spinosissimus and A. selousi. Based on this evidence, we described Acomys muzei sp. nov. and Acomys ngurui sp. nov., each one occurring separately along one side of the Eastern Arc Mountains. Finally, we lacked sufficient information to describe a third new species from the area north of the Zambesi River.

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Multivariate morphometries of the Ethiopian populations of harsh‐furred rat (Lophuromys: Mammalia, Rodentia)

July 2009

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32 Reads

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15 Citations

We investigated the geographic variation of eight Ethiopian populations of the rodent Lophuromys flavopunctatus and compared them to the Bale endemic species L. melanonyx. We used multivariate morphometrics and analysed independently skull and external body linear measurements, in an attempt to relate morphological variability to geography (latitude, longitude, altitude). There is a high morphological diversity in these Ethiopian populations, which form three distinct recognizable groups, with the Bale population being the most distinct. The results of analyses on the two character sets corroborate each other and indicate that the kind of variation is not ‘ecological’ but rather there is a phylogenetic cause, and relations at higher taxonomic level are suggested. There is a homogeneous group with five populations within which there is a recognizable pattern of clinal variation related to altitude, with a decrease in body size and a change in skull shape.


Allometry and chromosomal speciation of the casiraguas Proechimys (Mammalia, Rodentia)

April 2009

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86 Reads

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5 Citations

Morphometric characters (linear measurements) of the skull and mandible of the rodent Proechimys occurring in Venezuela and Columbia were investigated through multivariate techniques in order to describe static allometry and to relate allometric patterns to the recent evolution of these taxa. At least five species originated during the recent Pleistocene period in the upper Orinoco basin, all characterized by different karyotypes, one of them (P. guairae) being a Rassenkreis of karyomorphs. Species are characterized by unique static allometric patterns and the study of these patterns suggests a phylogenetic rather than an ecogenetic origin for these patterns; modifications in the shape of the skull and the mandible have originated during phyletic speciation and there is no apparent sign of functional adaptation. Allometrie und chromosomale Speziation bei den Casiraguas der Gattung Proechimys (Mammalia, Rodentia) Morphometrische Parameter (lineare Maße) des Schädels und der Mandibel von Nagetieren der Gattung Proechymis, die in Venezuela und in Kolumbien vorkommen, wurden mit Hilfe multivariater Analysemethoden untersucht, um die statische Allometrie zu beschreiben und die Allometriemuster mit der jüngeren Evolutionsgeschichte der Arten in Beziehung zu setzen. Im oberen Pleistozän haben sich im Orinoco-Becken mindestens fünf Arten entwickelt, die alle einen unterschiedlichen Karyotyp aufweisen, wobei eine Art (P. guairae) einen Rassenkreis von Karyomorphen darstellt. Die Arten weisen alle ein charakteristisches einmaliges und stabiles Allometriemuster auf. Die Studie läßt jedoch vermuten, daß diese Muster eher phyletischen als ökogenetischen Ursprung haben. Die Verschiedenheiten in der Form der Schädel und der Mandibeln gehen auf die phylogenetsichen Artbildungsprozesse zurück und es finden sich keine deutlichen Hinweise auf eine funktionelle Adaptation.


Systematics and geographic variation of Ethiopian Arvicanthis (Rodentia, Muridae)

March 2009

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66 Reads

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46 Citations

Arvicanthis, the unstriped grass-rat, is a widespread genus occurring in many regions of Africa and is major pest in agricultural farmland. Despite its economic importance for developing countries, the taxonomy of the genus is stillin a chaotic state. We used univariate and multivariate morphometrics to investigate two species, A. abyssinicus and A. dembeensis, occurring in Ethiopia. Results show that these taxa are well separated, this contradicting authors who lump all Arvicanthis as A. niloticus. There is a longitudinal cline in the morphology of A. dembeensis from eastern regions along the Rift Valley. Differences between the species in morphlogy seem to reflect adaptation to different ecological niches at high (A. abyssinicus) and low (A. dembeensis) altitudes.


Chromosomal polymorphisms in subterranean mole rats: origins and evolutionary significance

January 2008

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8 Reads

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10 Citations

Biological Journal of the Linnean Society

Two distinct chromosomal polymorphisms, among others, characterize the short (p) and long (qh) arms of chromosome number 1 of the Spalax ehrenbergi complex in Israel. We have studied the geographic distributions of these two polymorphisms in 60 animals belonging to four chromosomal species (2n= 52, 54, 58 and 60). These comprised 15 populations: 12 from continuously distributed populations, two from semi-isolates, and one isolate in the northern Negev Desert. Our results indicate that: (i) the two polymorphisms are widespread not only within populations and species but most strikingly between different bone marrow cells within an individual; this may reflect a diversity generating mechanism; (ii) the two polymorphisms of p and qh, primarily of p, are correlated with climatic factors of water availability and temperature, as well as geographical distances; these correlations are significantly above those expected by chance, (iii) The semi-isolates and the isolate display high levels of polymorphism in both p and qh, but particularly in qh, despite the small size population effects. We suggest that at least the polymorphism in p is involved in the adaptive radiation of mole rats into diverse climatic regimes. Furthermore, we speculate that the forces generating chromosomal polymorphisms relevant to speciation (i.e. Robertsonian mutations), coupled with the evolutionary forces operating in small peripherally isolated populations, may be appropriate for the origin of new chromosomal species through peripatric speciation.


Chromosomal speciation and phenotypic evolution in the house mouse

January 2008

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73 Reads

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54 Citations

Biological Journal of the Linnean Society

Chromosomal races of the house mouse (Mus musculus domesticus) in Valtellina and Orobian Alps (Northern Italy) are known for their very fast raciation. Here we present a study using geometric morphometries on size and shape changes in the skull and the mandible of three races (Orobian, Upper Valtellina, Poschiavo) occurring in this area and forming a presumably monophyletic group. One of the races (Upper Valtellina) went extinct recently in an area of sympatry with the Poschiavo race, so that data on genetics (chromosomes and allozymes), behaviour and morphology were available to investigate causes of phenotypic divergence during speciation with a recent extinction event. The evaluation of partial warp scores and the uniform component shows that morphological changes have been fast and that these races can be recognized on the basis of skull shape. Patterns of evolution in shape changes were visualized by combining the chromosomal phylogeny and shape space, summarizing therefore both the phenetic and cladistic relationships. Shape changes follow the cladogenetic sequence depicted by chromosomal fusions. The examination of Procrustes distances shows that the different parts of the skull evolved at different rates after speciation, with shifts in the integration of the various structures (olfactory, auditory, feeding, visualization, etc.). Among the possible causes, aggressive behaviour was advocated for sudden changes in the shape of the skull.


Fig. 2 Metaphases plates of males and females specimens of Acomys sp. (a) C-banded metaphase plate (2n = 61) of the TZ507 male specimen. (b): C-banded metaphase (2n = 59) of the female TZ521. (c) standard stained metaphase of the female TZ521 (2n = 60) showing the two evident giant sex chromosomes. (d) C-banded metaphase (2n = 60) of the female TZ511. (e) diakinesis of the male TZ507. In the frame, a bivalent from another plate is shown. In the photos, the X chromosome is indicated with a large arrow, the Y chromosome with a small arrow and the odd submetacentric with a arrowhead  
Fig. 1 Comparison of G-banding patterns between chromosomes of Acomys spinosissimus and Acomys sp. (males). For each triplet, the first two chromosomes on the left are of A. spinosissimus, while in the inset the corresponding chromosome of Acomys sp. is shown (autosome numeration according to  
of diploid numbers in bone marrow cells of males and females specimens of Acomys sp.
The origin of an unusual sex chromosome constitution in Acomys sp. (Rodentia, Muridae) from Tanzania

November 2007

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194 Reads

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12 Citations

Genetica

This paper describes a case which presents an evident variation from the "standard" XX/XY sex chromosomal constitution in a rodent, Acomys sp. This species known to be found in three localities of East Africa has only recently been separated from A. spinosissimus, its closest relative. In our study, five specimens of Acomys sp. and eight specimens of A. spinosissimus were live-trapped in five localities. Comparisons between the two taxa assed by G-banding show a complete homology in the chromosomal shape and banding pattern for 29 pairs of chromosomes corresponding to the complete autosomal set of A. spinosissimus. However, while all the A. spinosissimus analysed have 2n = 60 and a XY-XX system, in Acomys sp. males and females constitute mosaics for sex chromosomes in the bone marrow cells. Females (2n = 59, 60) have an excess (97%) of aneuploid cells with one single giant X chromosome, and males (2n = 60, 61) show X0/XY cells occurring in somatic tissues and XY cells in the germinal lineage. In addition, an odd heterochromatic submetacentric chromosome was identified in all the cells examined in two males and a female of Acomys sp. Since this chromosome was not related to sex determination and it is not present in all the analysed specimens, it can be considered as a B chromosome. Finally, the in situ fluorescence hybridisation (FISH) with telomeric probes showed a very intense interstitial telomeric signal (ITS) at the medial part on the long heterochromatic arm of the X chromosome. This could be due to recent chromosomal rearrangement.


Figure 1: Distribution of chromosomal races and hybrids in the Aeolian Archipelago following Amori et al. (1983).
Figure 2: G-banded karyotype of a female mouse from Vulcano (2n=26) with metacentrics Rb(1.2), Rb(3.9), Rb(4.13), Rb(5.14), Rb(8.12), Rb(10.16) and Rb(15.17).
A new chromosomal race of the house mouse, Mus musculus domesticus, in the Vulcano Island-Aeolian Archipelago, Italy

August 2007

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580 Reads

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17 Citations

Hereditas

In this paper we describe a new Robertsonian (Rb) race of the house mouse from Vulcano (Aeolian archipelago) through the identification of the metacentric chromosomes. We analysed fifteen mice. All the specimens were found to have the same karyotype 2n=26. This karyotype is characterized by Rb(1.2), Rb(3.9), Rb(4.13), Rb(5.14), Rb(8.12), Rb(10.16) and Rb(15.17). The differences between the race of Vulcano and the races in a neighbour island (Lipari) consist in the presence of Rb(10.16) and Rb(15.17) in the former and Rb(6.16) and Rb(10.15) in the latter. We discuss the possible hypotheses regarding the origin between these two races including the possible occurrence of a whole arm reciprocal translocation (WART) on the Vulcano island.


Fig. 1. Localities of the specimens used for the phylogenetic analysis (for geographical coordinates, see Table 1).  
Fig. 2. Bayesian 50% majority rule consensus tree obtained combining cytochrome b and 16S. Numbers are Bayesian posteriori probability, MP, ML, and NJ bootstrap values.  
Fig. 3. Bayesian 50% majority rule consensus tree (GTR + + I model). Numbers above branches are Bayesian posteriori probabilities, MP, ML and NJ bootstrap values. Diploid numbers for each lineage are reported (below branches). Letters for A–L indicate nodes for which age were estimated (see Table 3).  
Evolutionary systematics in African gerbilline rodents of the genus Gerbilliscus: Inference from mitochondrial genes

April 2007

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217 Reads

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45 Citations

Molecular Phylogenetics and Evolution

Gerbilliscus has recently been proposed as an endemic African rodent genus distinct from the Asian Tatera. A molecular phylogeny of the genus, including nine species from southern, western and eastern Africa, is presented here based on the analysis of the cytochrome b and 16S mitochondrial genes. With an adequate taxonomic sampling over a wide geographic range, we here provide a clear picture of the phylogenetic relationships between species and species groups in this genus. Three distinct clades were resolved, corresponding to major geographical subdivisions: an eastern clade that possibly diverged first, then a southern and a western clades which appeared later. We suggest two possible hypotheses concerning the dispersal of the genus across Africa, considering also the patterns of karyotypic variation. Finally, we discuss the taxonomic status of G. gambianus and the relationships between Gerbillurus and Gerbilliscus, as previous studies have suggested that the former should be included in the latter. Our data seem to support the synonymy of the two taxa and suggest that Gerbillurus and Gerbilliscus lineages diverged from a common ancestor appeared in eastern Africa.


Fig. 1
Table 8 .
Table 9 . Summary of the results of a discriminant analyses for all considered OTU's. [continued on next pages]
Table 11 . [cont.]
The Characterization of the Kilimanjaro Lophuromys aquilus True 1892 Population and The Description of Five New Lophuromys Species (Rodentia, Muridae)

January 2007

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622 Reads

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34 Citations

We revised the taxonomy of the Lophuromys flavopunctatus species complex based on craniometric measurements of > 3000 specimens and cytochrome b sequences of selected specimens collected throughout East Africa. Our approach, that consists of measuring skulls of a series of localities (topo-typical if possible), allowed us to compile a number of Operational Taxonomical Units (OTU’s) from across the geographic range of this species complex. The outcome of diverse multivariate analyses complemented with the available chromosomal data allowed us to (a) evaluate the craniometrical and genetic variation within this dataset, (b) to provide a more detailed characterisation of Lophuromys aquilus and laticeps, and (c) to identify five OTU’s that are described as new species.


Citations (72)


... The 2B-PLS identified linear combinations of Procrustes coordinates that maximized mutual covariance between the 2 arches. 22 The strength of this covariation was quantified using the correlation coefficient (r pls ) associated with the first PLS axis (PLS1) of each arch. To assess the statistical significance of this covariation, a permutation procedure was performed involving 1000 permutations. ...

Reference:

Dental arch shape in twins: A morphometric study of genetic influences
Use of Two-Block Partial Least-Squares to Study Covariation in Shape
  • Citing Article
  • December 2000

Systematic Biology

... Strikingly, although they are described as solitary, chromosomally distinct species present different ratios of aggressive and "pacifist" individuals. The Egyptian Spalax variant, which includes only "pacifist" animals, inhabits the aridest environment (Beiles et al., 1992) and can be distinguished by its shorter mandible (Corti et al., 1996). Furthermore, they present convergent genetic adaptations to the hypoxic environment (Fang et al., 2014;Zheng et al., 2022). ...

Size and shape variation in the mandible of the fossorial rodent Spalax ehrenbergi: A procrustes analysis of three dimensions
  • Citing Article
  • January 1996

... Secondly, our review highlighted that wellfunded large cross country collaborative projects (e.g. STAPLERAT; [74]; EcoRat; [26] are scientifically productive and may be the most appropriate avenues to establish long term projects which are required to produce robust estimates of abundance of rodents, and their damage and losses, with adequate spatial and temporal replication. ...

The present issue of the belgian journal of zoology contains the proceedings of the 9th international African small mammal symposium (ASMS), held at the sokoine university of agriculture, Morogoro, Tanzania from 14-18 July 2003

... Especially for costs, 3D photogrammetry is in fact interesting and increasingly applied in GMM, especially on mammals of both large (Evin et al., 2016) and small size ( Giacomini et al., 2019). This technique, pioneered in GMM by Fadda et al. (1997), allows to combine pictures of different views of an object to reconstruct a 3D model of its surface, thus, in a sense, 'transforming' a simple and relatively inexpensive digital camera in an accurate 3D scanner. 3D photogrammetry has made big technological progresses and, as the software for the construction of the 3D models is either free (Falkingham, 2012) or cheap (e.g., https://www.agisoft.com/), ...

A portable device for the three dimensional landmark collection of skeletal elements of small mammals

Mammalia

... Therefore, although they coincide with the geographic distribution, no other evidence would permit us to suggest that the chromosomal alterations directly influence the alteration in the cranium shape in C. lami. Márquez et al. (2000) suggest an association in cranial variation with karyotypic differences for Nephelomys albigularis, as synonym of Oryzomys albigularis like cited by Márquez et al. (2000) with linear morphometrics. Nevertheless, Chondropoulos et al. (1996) proposed that morphological variation is associated with geographical and not karyotype in Mus musculus. ...

Morphometric and chromosomal variation in populations of Oryzomys albigularis (Muridae: Sigmodontinae) from Venezuela: Multivariate aspects
  • Citing Article
  • April 2000

Zeitschrift fü Saugetierkunde

... Because PLS methods are sensitive to both vector magnitude and orientation, our use of correlation matrices does produce different results in our 2B-PLS tests than use of covariance matrices would (and indeed we did use unstandardized geometric morphometric landmarks in these analyses, to the same effect). However, use of a correlation matrix for instances in which data do not all exist on the same scale, as is the case here, is recommended by Rohlf and Corti (2000) and even required for uses of 2B-PLS in which a block of morphological data is associated with a block of environmental data or other nonmorphological data related to niche occupation, as environmental data are rarely on the same scale (Corti et al. 1996;Fadda and Corti 1998;Felice et al. 2019). ...

Geographic variation of Arvicanthis (Rodentia, Muridae) in the Nile Valley

Zeitschrift fü Saugetierkunde

... Όπως ήδη αναφέρθηκε, αυτό είναι ένα εξαιρετικά σπάνιο φαινόμενο στη φύση με λίγες μόνο περιπτώσεις σύλληψης τέτοιων ατόμων (Gropp et al., 1982;Hauffe & Searle, 1993;Nunes et al., 2011;Searle et al., 1993) σε σύνολο χιλιάδων που έχουν μελετηθεί κυτταρολογικά. Αντιθέτως, είναι πολλά τα παραδείγματα παραπατρικών Rb φυλών με μερική ομολογία βραχιόνων, οι οποίες δεν σχηματίζουν υβρίδια στη φύση ή δεν έχουν βρεθεί υβρίδια (Burt et al., 2009;Capanna, 1982;Castiglia et al., 2015;Castiglia et al., 2011). Με την παρούσα εργασία παραθέτεται για πρώτη φορά ο καρυότυπος τέτοιου ατόμου, αλλά και η μειωτική μετάφαση αυτού (Εικ. ...

Reproductive isolation between two chromosomal races of Mus musculus in the Rhaetian Alps (Northern Italy)
  • Citing Article
  • January 1982

Mammalia

... For this reason Discoglossus pictus is considered monotypic (Zangari et al., 2006). Capula and Corti (1993) found some morphological differences between the mainland populations and those occurring in Sicily and Malta, but this study included specimens of D. scovazzi. Populations of D. pictus present in southwestern Europe (Spain, France; Escoriza and Boix, 2012) are with certainty allochthonous; the founder population is situated in northern Algeria (Lanza et al., 1986;. ...

Morphometric variation and divergence in the West Mediterranean Discoglossus (Amphibia: Discoglossidae)
  • Citing Article
  • January 1993

... Traditional morphometric is a set of distance measurements of the biological structures, whereas, in the geometric morphometric technique, the landmark points or outlines are used to extract shape data (Mouludi-Saleh et al. 2020a). The geometric method has been described as an effective method in morphological studies compared to the traditional one (Loy et al. 1996;Radkhah et al. 2016) due to its higher efficiency in extracting shape data (Mouludi-Saleh et al. 2019;Nasri et al. 2019). ...

Shape Changes during the Growth of the Sea Bass, Dicentrarchus labrax (Teleostea: Perciformes), in Relation to Different Rearing Conditions
  • Citing Chapter
  • January 1996