identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
03F4DE25FFC8FA33FF26FA813623FCB5.text	03F4DE25FFC8FA33FF26FA813623FCB5.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Malpaisomys AND ITS	<div><p>BACKGROUND ON MALPAISOMYS AND ITS MAINLAND</p> <p>RELATIVES</p> <p>Malpaisomys insularis is known from Holocene and Pleistocene deposits (Hutterer et al., 1988; Michaux, Hutterer &amp; López-Martínez, 1991; Castillo, Martín- González &amp; Coello, 2001) in the eastern Canary Islands, including Fuerteventura, Lanzarote and nearby islets (Fig. 1). It became extinct during historical times, probably because of the arrival of man (Boye et al., 1992). Malpaisomys owes its name to the Spanish word, malpaís, meaning lava fields where its fossil remains are sometimes found in cavities. A study of its skeletal characteristics suggested that Malpaisomys lived in fissures opened in the lava fields (Boye et al., 1992).</p> <p>Its phylogeny, based on dental or skeletal characters, can at present only be hypothesized; these characters can be of poor value for phylogenetic reconstruction, especially because of cases of convergent evolution. Malpaisomys was first interpreted as related to Acomyinae (Hutterer et al., 1988). Acomyinae now constitutes a genetically well-identified group showing morphological convergence in dental pattern with the Murinae, in particular in the first two upper cheek teeth (Chevret, Michaux &amp; Catzeflis, 1993). Immunogenetic comparisons, however, cast some doubt on the relationships of Malpaisomys and Acomys, suggesting that Malpaisomys was more closely related to Murinae than to Acomyinae (Montgelard, 1992). This interpretation has been reinforced by the reconsideration of some dental features typical of murine rodents, such as the structure of the third upper molar (Denys &amp; Michaux, 1992). Consequently, Malpaisomys is now considered to be a true murine. In addition, Malpaisomys displays a dental specialization termed stephanodonty (Schaub, 1938; Misonne, 1969), which is characterized by the swelling of the cusps and the development of longitudinal crests that extend the cusps and join them in a garland-like pattern on the upper molars. Such a trend has been interpreted as an adaptation to a diet rich in green vegetation or grass by analogy with the extant African stephanodont murines Oenomys (Dieterlen, 1967) and Aethomys (Denys, 1994), and functional morphological arguments (Michaux, 1978; van Dam, 1997). The similarity of the dental patterns is stressed by the grouping of Malpaisomys together with the stephanodont murines Oenomys and Stephanomys (López-Martínez, Michaux &amp; Hutterer, 1998).</p> <p>Stephanodonty in Malpaisomys could be the result either of evolution from a stephanodont ancestor or of convergent evolution. In order to investigate both hypotheses, we compared Malpaisomys with murine rodents showing a stephanodont trend and with taxa exhibiting a basic murine dental pattern (Fig. 2). Stephanodont rodents include several fossil taxa and some tropical extant species. An evolutionary lineage leading to the evolution of stephanodonty starts in south-western Europe with Progonomys hispanicus evolving into Occitanomys. A cladogenesis around 7 Mya leads to Occitanomys alcalai on the one hand and to Stephanomys on the other (Michaux, 1971; van de Weerd, 1976; van Dam, 1997). The evolution along this lineage leads from small and primitive molars in P. hispanicus to large and specialized, highly stephanodont molars in Stephanomys, with Occitanomys having intermediate features (van de Weerd, 1976; Cordy, 1978; van Dam, 1997). Stephanodonty evolved independently along the lineage of Paraethomys (Jaeger, 1977; Coiffait, 1991; Benammi et al., 1995, 1996), a genus characteristic of North African rodent fauna from the Late Miocene until its extinction late in the Pleistocene (Jaeger, 1977; Jaeger, Michaux &amp; Thaler, 1975). Progonomys cathalai was present earlier than Paraethomys in North Africa, and compared to the latter it is characterized by a more primitive evolutionary stage in dental morphology. Consequently, it is considered in the present study as the morphological reference for an ancestor of the Paraethomys lineage. Within extant species, Oenomys displays complete stephanodonty (Misonne, 1969) while Aethomys shows some stephanodont characteristics (Denys, 1994).</p> <p>Malacomys, Praomys and Mastomys were chosen as examples of rodents characterized by a basic dental pattern associated with an omnivorous diet. Mastomys peregrinus was considered because its geographical range, including western North Africa, makes a colonization of the Canary Islands by this species more likely than by a tropical taxon (Fig. 1). The arvicanthine group (Ducroz, Volobouev &amp; Granjon, 2001) includes murine rodents with a herbivorous diet. Thallomys and Arvicanthis are part of this group but do not display stephanodont trends, unlike Aethomys and Oenomys. However Thallomys and Arvicanthis were included in order to evaluate the role of diet on the shape of molars.</p> </div>	https://treatment.plazi.org/id/03F4DE25FFC8FA33FF26FA813623FCB5	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Renaud, Sabrina;Michaux, Jacques	Renaud, Sabrina, Michaux, Jacques (2004): Parallel evolution in molar outline of murine rodents: the case of the extinct Malpaisomys insularis (Eastern Canary Islands). Zoological Journal of the Linnean Society 142 (4): 555-572, DOI: 10.1111/j.1096-3642.2004.00140.x, URL: https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2004.00140.x
03F4DE25FFCCFA36FCE0FB063634FB87.text	03F4DE25FFCCFA36FCE0FB063634FB87.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Malpaisomys AND	<div><p>COMPARISON OF MALPAISOMYS AND POSSIBLE</p> <p>RELATIVES</p> <p>Malpaisomys has been compared to different stages of the Progonomys – Occitanomys / Stephanomys and Paraethomys lineages, to Progonomys cathalai and to several modern taxa (Table 1). An important morphological differentiation exists for the first upper and lower molars (P &lt;0.001).</p> <p>For the upper molars, the first two canonical axes display most of the among-group differentiation (Fig. 3A). In the plane defined by the first (CA1, 46.3% of the among-group variance) and the second axes (CA2, 18.2%), the first cluster includes Progonomys associated with Mastomys, Praomys and Malacomys. All of these murine teeth are characterized by an asymmetrical outline. They also share a basic omnivorous murine diet. From this ‘omnivorous’ cluster the second cluster diverges along both CA1 and 2, including murines with broader and more symmetrical molar outlines. Among these taxa, those with a known ecology share a trend towards a herbivorous diet. This cluster of ‘intermediate’ outlines includes Mio-Pliocene Paraethomys, Occitanomys, the arvicanthines (except Oenomys), and Malpaisomys. From this cluster, Stephanomys (along CA1), the Pleistocene Paraethomys (mostly along CA2 with a component along CA1), and Oenomys (along CA2) show a further divergence. All these taxa are characterized by a typical stephanodont dental pattern associated with broader and more symmetrical outlines.</p> <p>The modern taxa Praomys, Malacomys and to a lesser extent Mastomys (Fig. 3B) are especially isolated on the third axis (10.3% of among-group variance). It appears to correspond to a phylogenetic signal of the Praomys - Malacomys group.</p> <p>The results based on the first lower molars (Fig. 3C) are less clear but suggest similar features than those based on the upper molars (Fig. 3A, B). The differentiation along CA1 (60.6% of the among-group variance) corresponds to a considerable divergence of Stephanomys, the most recent (LF4) being the most extreme. Along CA2 (20.5% of variance) Progonomys, associated with Malacomys, is opposed to Pleistocene Paraethomys. In between are found two clusters; the first includes the oldest Occitanomys and the Mio- Pliocene Paraethomys, Mastomys, Arvicanthis and Thallomys, the second includes more recent Occitanomys, Oenomys and Malpaisomys. CA2 therefore displays a trend from primitive towards more derived outlines, and Malpaisomys is associated with rather derived ones.</p> <p>The distribution of the taxa on these canonical axes might appear to be a simplification of the morphological signal and thus undermine the interpretation of the morphological differentiation as an ecological signal showing evolutionary grades. We therefore complemented the multivariate analysis by a cluster analysis of the raw data, focusing on the first upper molar shape. Distances were calculated from the Fourier coefficients and a phenetic tree was constructed using a UPGMA algorithm (Fig. 4). In agreement with the patterns observed on the canonical axes, outlines interpreted as ‘omnivorous’ are grouped together, including Progonomys, Malacomys, Praomys and Mastomys. Stephanomys appears as highly divergent. Derived, stephanodont Oenomys and Pleistocene Paraethomys are clustered and clearly separate from a cluster of outlines characterized by an intermediate stage of evolution: Occitanomys, Mio-Pliocene Paraethomys, the arvicanthines Aethomys and Arvicanthis, and Malpaisomys.</p> </div>	https://treatment.plazi.org/id/03F4DE25FFCCFA36FCE0FB063634FB87	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Renaud, Sabrina;Michaux, Jacques	Renaud, Sabrina, Michaux, Jacques (2004): Parallel evolution in molar outline of murine rodents: the case of the extinct Malpaisomys insularis (Eastern Canary Islands). Zoological Journal of the Linnean Society 142 (4): 555-572, DOI: 10.1111/j.1096-3642.2004.00140.x, URL: https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2004.00140.x
03F4DE25FFC5FA3CFCB8FE0F33ACFA55.text	03F4DE25FFC5FA3CFCB8FE0F33ACFA55.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Malpaisomys WITH	<div><p>RELATIONSHIPS OF MALPAISOMYS WITH MAINLAND</p> <p>TAXA</p> <p>Within this morphological pattern among modern and fossil taxa, Malpaisomys clearly falls within the intermediate cluster of herbivorous diet. This supports a palaeoecological interpretation of the taxon as herbivorous, but poses the problem of identifying its mainland ancestor. In particular, herbivory could either be inherited from this ancestor or the result of a parallel evolution on the islands.</p> <p>Island populations of rodents are known to frequently display an increase in size compared to mainland relatives (Foster, 1964). A decrease in size associated with insular conditions therefore seems unlikely, and is in any event rare in evolutionary lineages (Fig. 7C). Such an interpretation excludes large taxa as being potential ancestors of Malpaisomys, especially Aethomys, Arvicanthis, Thallomys, Pleistocene Paraethomys, and Late Pliocene Stephanomys. Shape, by contrast, reveals a different pattern. Among modern taxa, Aethomys (and to a lesser extent, Arvicanthis) are the most similar regarding first upper molar shape (Figs 3, 4B) while Malacomys and Praomys are the most different (Fig. 7D). Some discrepancies exist between the shape of the first upper or lower molars. Based on the upper molars, the extreme stephanodonts Oenomys, Pleistocene Paraethomys and Pliocene Stephanomys appear to be more differentiated than Malpaisomys, which would be closest to Occitanomys (e.g. O-MTH) or Late Pliocene Paraethomys (Fig. 3B). Based on the first lower molar shape, however, Malpaisomys appears to be closer to the more derived, Pleistocene Paraethomys, while remaining associated with Late Pliocene Occitanomys (Fig. 3C). In agreement with our results, the morphological relatedness of the stephanodont genera Malpaisomys, Oenomys and Stephanomys had previously been shown by phenetic distances of dental characters (López-Martínez et al., 1998). Skull characters provide a different picture, suggesting a similarity between Stephanomys and Malpaisomys, Oenomys having been found to be more similar to non-stephanodont genera like Rattus (López-Martínez et al., 1998). Mosaic evolution likely occurred due to diverse selective pressures acting on different characters. The skull is more influenced by habitat whereas dental patterns reflect diet. The similarity of the skulls of Malpaisomys and Stephanomys may be a consequence of a similar mode of life within a rocky landscape (López- Martínez et al., 1998).</p> <p>Combining these various results shows that morphologically the taxa closest to Malpaisomys are to be found among Pliocene fossil lineages related to either Paraethomys or Occitanomys. A hypothesized colonization of the eastern Canary Islands by members of these genera minimizes the evolution in both size and shape. A third alternative is colonization by an ancestor of the arvicanthine group, smaller in size than the modern representatives and already displaying a morphology characteristic of the intermediate, herbivorous group. Gene flow between mainland and canarian populations has been promoted by low sea level during glacial periods in some birds (Idaghdour et al., 2004). However, any hypothesis considering such a recent colonization event for Malpaisomys would imply extremely high evolutionary rates and reversion in size and/or shape. Morphometric methods favour hypotheses which minimize morphological distance and evolutionary rates. Nonetheless, observations of the fossil lineages (Fig. 7) consistently reveal that such high rates and reversion seldom occur. We therefore favour the hypothesis of an ancient colonization event by a mainland taxon already exhibiting a trend toward herbivory.</p> <p>Biogeographical considerations should also be considered when evaluating the different hypotheses of colonization. The sea-surface current system around the Canary Islands (Stramma &amp; Siedler, 1988), as well as the dominant trade winds, favour a colonization event from North Africa or the Iberian Peninsula (Fig. 1), providing additional support for a relatively ancient colonization event involving Paraethomys or Occitanomys. A Late Miocene or Pliocene colonization leading to Malpaisomys has been previously suggested (Hutterer et al., 1988; Michaux et al., 1991) and is supported by our results. This hypothesis is not contradicted by dating of the insular volcanic complex, indicating that subaerial areas in the eastern Canary Islands are as old as 15 Myr (Carracedo &amp; Soler, 1995; Ancochea et al., 1996).</p> </div>	https://treatment.plazi.org/id/03F4DE25FFC5FA3CFCB8FE0F33ACFA55	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Renaud, Sabrina;Michaux, Jacques	Renaud, Sabrina, Michaux, Jacques (2004): Parallel evolution in molar outline of murine rodents: the case of the extinct Malpaisomys insularis (Eastern Canary Islands). Zoological Journal of the Linnean Society 142 (4): 555-572, DOI: 10.1111/j.1096-3642.2004.00140.x, URL: https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2004.00140.x
03F4DE25FFC4FA3CFF66F9DF37B9FC8A.text	03F4DE25FFC4FA3CFF66F9DF37B9FC8A.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Malpaisomys	<div><p>DIFFERENTIATION AMONG MALPAISOMYS</p> <p>POPULATIONS</p> <p>After the colonization event, the ancestor of Malpaisomys may have evolved into the endemic form within an isolated gene pool. This evolution cannot be tracked in the fossil record because the oldest Pleistocene deposits in the eastern Canary Islands are of Malpaisomys rather than an intermediate form. Still, its late evolution during the Pleistocene until its extinction during historical times can be assessed. Preliminary results emerge from the four deposits examined. A morphological difference is observed between the Pleistocene and the Holocene populations from Fuerteventura (Table 2). During this time interval, Mus colonized the islands and began to feature greatly in the deposits (Michaux et al., 1996; Castillo et al., 2001). The invasion of an island by a generalist competitor has been observed to cause a size decrease of the resident species in several small mammals (Yom- Tov, Yom-Tov &amp; Moller, 1999). The size decrease and shape difference among Malpaisomys populations may thus document a response to the arrival of the generalist house mouse. Still, the evolutionary rate estimated for this evolution (Fig. 7) does not differ from observations of fossil lineages, suggesting that the new ecological interaction did not trigger an exceptionally rapid morphological evolution.</p> <p>The population of the islet Lobos (4.6 km 2) also differentiated from the Holocene populations in Fuerteventura (1633 km 2; Fig. 5), although the presence of Mus suggests a similar age. This may document a smallscale insularity effect due to partial genetic isolation.</p> </div>	https://treatment.plazi.org/id/03F4DE25FFC4FA3CFF66F9DF37B9FC8A	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Renaud, Sabrina;Michaux, Jacques	Renaud, Sabrina, Michaux, Jacques (2004): Parallel evolution in molar outline of murine rodents: the case of the extinct Malpaisomys insularis (Eastern Canary Islands). Zoological Journal of the Linnean Society 142 (4): 555-572, DOI: 10.1111/j.1096-3642.2004.00140.x, URL: https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2004.00140.x
