The genus Hypnomys Bate, 1918 includes some endemic Neogene chronospecies from Mallorca and Menorca, evolved in insularity conditions from the Lower Pliocene to the human arrival at the archipelago. The study of the allometric proportions (functional length and sagittal diameter) of the limbs’ long bones of Hypnomys eliomyoides Agusti, 1980 (Lower Pleistocene of Menorca), Hypnomys sp. (Pleistocene of Menorca), Hypnomys onicensis (Reumer, 1994) (Upper Pliocene-Lower Pleistocene of Mallorca) and Hypnomys morpheus Bate, 1918 (Upper Pleistocene of Mallorca) only indicates small differences with the garden dormouse (Eliomys quercinus Linnaeus, 1776) and other mainland rodents and insectivores. The study about the locomotion type by means of Similarity Matrix of Bou indicates that 1) Hypnomys spp. presents the greater similarities with the arboreal, jumping and gliding species; 2) the jumping and digging life style of Hypnomys spp. are more developed (25%) than in E. quercinus; 3) the walking locomotion of Hypnomys spp. is only a 7% greater than in E. quercinus; and 4) the degree of similarity with the gliding locomotion of Hypnomys sp. is greater (17%) than in E. quercinus. Some of this data indicates that Hypnomys spp. was better adapted to the arboreal life than E. quercinus, due to the relationship between the jumping and gliding capacities with the arboreal locomotion. The greater similarity of Hypnomys spp. with the walking locomotion does not necessarily involve more terrestrial habits. Our interpretation contrasts with earlier conclusions of Hypnomys life style (Hypnomys cf. onicensis and Hypnomys morpheus) where the terrestrial locomotion was overestimated in front of the arboreal locomotion. The locomotion type of Hypnomys would be related with the presence of important forest masses on the Balearic Islands during the Neogene, a different degree of environmental stress from that of the mainland ecosystems and a probable expansion of the ecological niche occupied by these species.
Le genre Hypnomys Bate, 1918 inclut certaines chrono-espèces néogènes endémiques de Majorque et Minorque, qui ont évolué dans des conditions insulaires, depuis le Pliocène inférieur jusqu’à l’arrivée de l’Homme sur l’archipel. L’étude des proportions allométriques (longueur fonctionnelle et diamètre sagittal) des os longs d’Hypnomys eliomyoides Agusti, 1980 (Pléistocène inférieur de Minorque), Hypnomys sp. (Pléistocène de Minorque), Hypnomys obicensis (Reumer, 1994) (Pliocène supérieur–Pléistocène inférieur de Majorque) et Hypnomys morpheus Bate, 1918 (Pléistocène supérieur de Majorque) n’indique que de petites différences par rapport au loir de jardin (Eliomys quercinus Linnaeus 1776) et à d’autres rongeurs et insectivores terrestres. Une analyse du type de locomotion au moyen de la Similarity Matrix (matrice de similitude) de Bou indique : 1) que Hypnomys spp. présente les plus grandes ressemblances avec les espèces arboricoles, sauteuses et glisseuses ; 2) que les modes de vie de type saut et creusement d’Hypnomys spp. sont plus dérivés (25 %) que chez E. quercinus ; 3) que le mode locomoteur de marche d’Hypnomys spp. est seulement supérieur de 7 % à celui d’E. quercinus ; et 4) que le degré de ressemblance avec la locomotion de type glisse d’Hypnomys sp. est supérieur de 17 % chez E. quercinus. Certaines de ces données indiquent qu’Hypnomys spp. était mieux adapté à la vie arboricole qu’E. quercinus, d’après des ressemblances déduites de ses capacités de saut et de glisse et celles de la locomotion arboricole. La plus grande ressemblance d’Hypnomys spp. concernant des traits corrélatifs de la locomotion de type marche n’implique pas nécessairement de mode de vie plus terrestre. Notre interprétation contraste avec des conclusions antérieures sur le style de vie d’Hypnomys (Hypnomys cf. onicensis et Hynomys morpheus), selon lesquelles la locomotion terrestre a été surestimée en comparaison de la locomotion arboricole. Le mode de locomotion d’Hypnomys serait lié à la présence d’importantes zones forestières sur les Baléares pendant le Néogène, un degré de stress environnemental différent de celui des écosystèmes terrestres et une probable expansion des zones, nécessitant une adaptation pour ces espèces.
Neogene insular faunas, Western Mediterranean, Similarity matrix of Bou, Locomotion trends, Ecological niche, Birds of preyFaunes insulaires néogènes, Méditerranée occidentale, Similarity Matrix de Bou, Tendances locomotrices, Niche écologique, Oiseaux de proiepresentedHandled by Lars van den Hoek OstendeIntroduction
The vertebrates evolved in insularity conditions show changes affecting size and body proportions, locomotion type, behavior, physiology, life cycle and ecological niche (Alcover, 1988a, Alcover, 1988b, Azzaroli, 1971, Köhler and Moyà-Solà, 2009, McNab, 2002, Sondaar, 1977 and Van der Geer et al., 2010). These changes are well documented in endemic terrestrial mammals from the Miocene, Pliocene and Pleistocene of the Balearic Islands (Agusti et al., 1982, Alcover et al., 1981, Alcover et al., 1999, Bate, 1909, Bate, 1918, Bate, 1944, Jordana et al., 2012, Köhler, 2010, Köhler and Moyà-Solà, 2001, Köhler and Moyà-Solà, 2004, Köhler and Moyà-Solà, 2009, Quintana, 1993, Quintana and Agustí, 2007 and Quintana et al., 2011). Studies about locomotion and body proportions have been focused principally on large mammals (the fossil Balearic goat, Myotragus balearicus Bate, 1909 [Bover et al., 2005, Köhler and Moyà-Solà, 2001, Köhler and Moyà-Solà, 2004, Leinders, 1979, Leinders and Sondaar, 1974, Moyá-Solá, 1979 and Sondaar, 1977] and the giant rabbit of Minorca, Nuralagus rex Quintana, et al., 2011, while those related with rodents and insectivores of small size, including the genus Hypnomys Bate, 1918 (Bover et al., 2010, García-Martínez et al., 2011, Mills, 1976 and Quintana and Arnau, 2004), Muscardinus Kaup, 1829 (Gliridae), Tragomys Agusti, et al., 2012 (Cricetidae) and Nesiotites Bate, 1944 (Soricidae), have been scarce or inexistent.
A recent study of the body shape and life style of Hypnomys cf. onicensis (Reumer, 1994) and Hypnomys morpheus Bate, 1918 from Mallorca based on statistical analyses (factorial discriminant analysis and postcranial indexes), offers complex results that do not allow clear conclusions (Bover et al., 2010: p. 9). These authors affirm that these two species showed a more terrestrial and fossorial life style and proportionally more elongated zeugopodium than the extant garden dormouse (Eliomys quercinus Linnaeus, 1766).
Objectives
In view of the Bover et al. (2010) conclusions, we would like to compare their results using an alternative method (Similarity Matrix of Bou), in order to know with more precision the locomotion type and allometric changes in zeugopodium (tibia and ulna) and stylopodium (femur and humerus) of Hypnomys from five paleontological deposits from Menorca and Mallorca. Moreover, we think that it would be interesting to compare several island species with important body mass differences (Hypnomys spp. versus M. balearicus and N. rex), for knowing if limbs proportions have changed similarly in all cases, as both M. balearicus and N. rex show shorter limbs compared to mainland bovids and leporids respectively (Quintana et al., 2011 and Sondaar, 1977).
MethodsSamples
Studied samples come from three sites in Menorca (Barranc de Binigaus: Hypnomys eliomyoides Agusti, 1980 [Lower Pleistocene]; Sa Cigonya: Hypnomys sp.1 [Pleistocene]; deposit 17 from Punta Esquitxador: Hypnomys sp.2 [Pleistocene]) and from two sites in Mallorca (Pedrera de s’Ònix: Hypnomys onicensis [Upper Pliocene–Lower Pleistocene]; Cova de sa Bassa Blanca: H. morpheus [Upper Pleistocene]) (Fig. 1). The complete descriptions of these deposits are in Moyà-Solà and Pons-Moyà, 1979 and Moyà-Solà and Pons-Moyà, 1980 (Cova de sa Bassa Blanca and Barranc de Binigaus), Alcover et al. (1981) (Pedrera de s’Ònix) and Quintana (1998) (Sa Cigonya and deposit 17 from Punta Esquitxador).
In two sites (Barranc de Binigaus and deposit 17 from Punta Esquitxador) it was necessary the use of acetic acid for separating the bones from the matrix. Specimens of H. onicensis and H. morpheus are housed in Institut Català de Paleontologia Miquel Crusafont (ICP, Sabadell, Spain), while those of H. eliomyoides and Hypnomys sp. are stored in the paleontological collection of one of the authors (JQ).
Body mass
High body size variation is observed between the five studied deposits. As a consequence of these differences, the body mass of each deposit was estimated in order to compare the allometric changes of each studied population. The body masses were estimated from the low tooth row length (LTRL), following the equation ln(body mass) = −0.6196 + 2.7020 ln(LTRL) (Hopkins, 2008) (Table 1).
Measurements of postcranial bones
Functional lengths and sagittal diameters of femur, tibia, humerus and ulna were measured following the criteria of Bou (1988) (Fig. 2). A digital caliper with an error margin of ± 0.02 mm was used. Graphics that relate lengths and sagittal diameters were carried out using only complete bones, which allows us to measure both parameters simultaneously.
Diagrams
The regression models (Fig. 3, Fig. 4, Fig. 5 and Fig. 6), allometric relationships among body mass and skeletal dimensions (functional length versus sagittal diameter), were created following the criteria and data published in Bou et al. (1987: Table 2, p. 116). These models were constructed with a total of 46 species of insectivores, elephant shrews and rodents included in the families Chrysochloridae (2 species), Erinaceidae (2 species), Soricidae (5 species), Talpidae (2 species), Macroscelidae (2 species), Sciuridae (5 species), Geomyidae (1 species), Castoridae (2 species), Cricetidae (4 species), Spalacidae (1 species), Rhizomyidae (1 species), Arvicolidae (6 species), Muridae (4 species), Gliridae (2 species), Hystricidae (1 species), Caviidae (2 species), Hydrochaenidae (1 species), Dasyproctidae (2 species) and Myocastoridae (1 species), showing an important body mass variation (Bou et al., 1987: figs. 2, 4, 6 and 8). The relative position of Hypnomys spp. in the regression models is compared with E. quecinus. Diagrams axes are in log 10 scale, lineal measurements in centimeters and body masses in grams.
Similarity matrix of Bou
Method based on the allometric proportions (functional length versus sagittal diameter) of the long bones of the limbs of some extant mammal species, of which the locomotion type is known in relation to their position respect to the different regression lines. Bou (1988) made regression models (among sagittal diameter, functional length and body mass of the femur, tibia, humerus and ulna) and a matrix with the 46 studied species (with know locomotion type). Each one of these species is located over (+), under (−) or coincided with the regression line (=). This information (locomotion type in relation to the position of the species on the regression line) was recorded in a simplified matrix (Bou, 1988, Table 10) where each locomotion type is characterized by 12 symbols (+, − or =), representing each of the studied morphological traits (three different regression models by the four limbs’ long bones). The locomotion type of an extinct species is established by Bou (1988) from the similarity degree (as a percentage) among the 12 symbols that characterize each locomotion type and the symbols of the extinct species.
Main results
The study of the allometric changes offers high homogenous results for the samples from Menorca and Mallorca (Table 2). We have not found remarkable differences between functional length and sagittal diameter of the femur, tibia, humerus and ulna of Hypnomys spp. compared with E. quercinus and some mainland rodents and insectivores (Fig. 3, Fig. 4, Fig. 5 and Fig. 6).
The results offered by the Bou's Similarity Matrix (Table 3) indicate that Hypnomys spp. and E. quercinus show a degree of overlapping similar (92%) to the arboreal species (Fig. 7). Hypnomys spp. is a 25% better adapted for the jumping and digging than E. quercinus and a 17% better adapted for the gliding locomotion. In regard to the walking species, Hypnomys spp. is (compared to E. quercinus) better adapted (7%) to this type of locomotion. These results (with the exception of those related with the digging locomotion) agree with the phenogram obtained by Bou (1988: fig. 26) and indicate the better adaptation of Hypnomys spp. for the arboreal life, given that the jumping and gliding capabilities are tightly related to the arboreal life (Bou, 1988). It seems obvious, from a taxonomical point of view, that Hypnomys was not a gliding species in the narrowest sense of the term. On the other hand, the greater walking capability of Hypnomys spp. does not necessarily involve a life habits more terrestrial, because this type of locomotion can also be related with the arboreal life style and the way how Hypnomys spp. dwelled in this kind of habitat.
Discussion
Non-cursorial mammals (as small sized rodents) are those that race only occasionally, accelerating their bodies during a short period of time. This fast acceleration entails a great energetic cost. The stylopodium of non-cursorial mammals is slightly abducted. From a postural point of view, they take up an intermediate position between cursorial animals, with slightly flexed (upright), and sprawling ones, those with highly flexed limbs (Hildebrand, 1985). Cursorial mammals are characterized by highly straight limbs, slightly or no abducted longer bones (especially metapodials and stylopodium's bones) than the non-cursorial mammals with a gravity center farther from the ground (Hildebrand, 1985).
The obtained results of the tibia's and ulna's functional length of Hypnomys spp. do not coincide with the analysis realized by Bover et al. (2010) from an unique individual (Bover et al., 2010: table S6), who observed a lengthening of the zeugopodium bones. Bover et al. (2010) documented the first case of limbs’ lengthening in a Balearic Neogene endemic vertebrate. Our results do not confirm this.
The body reconstruction of H. cf. onicensis and H. morpheus (Bover et al., 2010; figs. 6 and 7) shows a specimen with less flexed limbs than E. quercinus. Concerning this, the more terrestrial life style and the limbs’ lengthening emphasized by Bover et al. (2010) implies important postural and locomotion modifications in these two species. These traits seem to be more appropriate of a cursorial mammal than of a typical insular one. In an insular environment, where trophic resources are more limited and lower predation pressure exists, the lengthening and less flexion of the limbs are not the optimal solution from an energetic and postural point of view (Biewener, 1990 and Van der Geer et al., 2010: p. 361).
Regarding this, the evolutionary trends of two typical insular mammals as M. balearicus and N. rex point in opposite direction. In other words, in both cases it is observed that there is a reduction of the limbs length and an approach of the body gravity center to the ground. Locomotion of M. balearicus and N. rex is slower, more stable and powerful than that of their mainland ancestors (Quintana et al., 2011 and Sondaar, 1977). From this point of view, the evolutionary trends observed in these two mammals are clearly different from those of Hypnomys. In this case no remarkable allometric changes are related with functional lengths and sagittal diameters of the limbs’ long bones. Limbs proportions (and the arboreal life style) of Hypnomys spp. could be explained, in part, by the birds of prey's pressure, whose existence is well-documented in the Pliocene and Pleistocene of the Balearic archipelago (Seguí, 1998). Despite this, the total stress balance would be lesser than that from the mainland, bone histology results of Hypnomys disclose a delay of the maturation and a higher expectancy (9 years) compared with E. quercinus (García-Martínez et al., 2011).
Conclusions of Bover et al. (2010) about locomotion of Hypnomys spp. overestimate the degree of terrestriality in front of the arboreal aptitudes of H. cf. onicensis and H. morpheus, although a low probability percentage was obtained by Bover et al. (2010) for this kind of locomotion (P = 3.3%) in comparison to the arboreal one (P = 74.6%).
The analysis by Bover et al. (2010) also includes data about the extant populations of E. quercinus from the Balearic Islands (Formentera and Mallorca-Menorca), characterized by significant differences in body size as a consequence of a supposed insular differentiation. Those differences are used (in a subtle way) to establish a correlation between the increase of body size and their more terrestrial life style, as it occurs, presumably, in H. cf. onicensis and H. morpheus. Correlation between body size and locomotion (supported by the factorial discriminant analysis) disagrees with the fact that extant populations of E. quercinus from the Balearic Islands are related with relatively recent introductions from mainland populations with several origins, but with similar locomotion aptitudes. According to Alcover, 1988a and Alcover, 1988b and Moreno (2002), Formentera's population forms part of the lusitanicus group, distributed in the South-West of the Iberian Peninsula and characterized by a large size, while populations from Mallorca and Menorca would form part of the quercinus group, characterized by individuals of less size that would take up an important part of the Iberian Peninsula. Thus in this case, the discriminant analysis would not be useful to verify supposed “insular divergences” (Bover et al., 2010), but it seems to confirm different geographical origins of the Balearic populations of E. quercinus.
Conclusions
The study of the allometric changes regarding the functional length and sagittal diameter of the femur, tibia, humerus and ulna shows that proportions of Hypnomys spp. are similar to E. quercinus.
Taken together, the results of the Similarity Matrix of Bou indicate a clear predominance of the arboreal locomotion for Hypnomys spp. and more developed digging skills than E. quercinus. Some results obtained by Bover et al. (2010) point to the same direction. However, these authors give, surprisingly, greater weight to the terrestrial locomotion, although it has a low probability. The absence of allometric changes in the length of the limbs’ long bones observed in our analysis are in contradiction to the results of Bover et al. (2010). Our results would be related with the existence of woodlands on the Balearic Islands during the Neogene (Alcover et al., 2000, Bauzà, 1971, Colom, 1978, López de Heredia et al., 2005 and Pérez-Obiol et al., 1996).
The results of the proportions of limbs’ long bones of Hypnomys spp. are interesting, considering that some of them (greater width of the distal humerus) (Bover et al., 2010) are congruent with the observations of other larger insular mammals (M. balearicus and N. rex) (Alcover et al., 1981 and Quintana, 2005). On the other hand, Hypnomys spp. does not show significant allometric changes of the relative proportions of functional length and sagittal diameter of the limbs’ long bones. It is likely that differences of the relative length of the limbs’ long bones between Hypnomys spp. and N. rex/M. balearicus would be related to their body size and the probability to be hunted by birds of prey. The absence of significant allometric changes in relative length of the limbs’ long bones would be the evolutionary response to predation in Hypnomys spp. The absence or the low predation pressure on N. rex and M. balearicus caused some of their locomotion trends and triggered some significant allometric changes. Although it is true that the morpho-skeletal traits of the mainland ancestor of Hypnomys spp. are unknown, it is possible that the existence of a supposed “conservative” corporal proportions (related to arboreal locomotion) with other “innovative” tendencies (related to more developed digging skills) are associated, to a certain extent, with the environmental stress exercised by birds of prey. Perhaps, this type of predation stopped certain skeletal changes (significative variation in the length of the limbs’ long bones), but it did not prevent the promotion of the ethological traits related to the digging and the enlargement of the ecological niche, because, as it has been mentioned before, the environmental stress assessment was lesser than that from the mainland.
Acknowledgments
We are especially grateful to Dr. Josep Antoni Rosselló (Jardí Botànic de València-Universitat de Valencia and Jardí Botanic Marimurta de Blanes) for the bibliographic suggestions. We would like to give special thanks to Dra. Meike Köhler (ICP, Bellaterra, Spain) for her revision and valuable suggestions on the manuscript. We would like also thank the accurate critiques and comments, as well as the patience, of the reviewers and editors. This work was supported by the Ministerio de Economia y Competitividad, Gobierno de España (JQC, I+D MINECO CGL2012-34459) and the Ministerio de Educación, Cultura y Deporte, Gobierno de España (BM-S, AP2010-2393).
AgustiJ.Moyà-SolàS.Pons-MoyàUne espèce géante de Muscardinus Kaup, 1829 (Gliridae, Rodentia, Mammalia) dans le gisement karstique de Cala es Pou (Miocène supérieur de Minorque, Baléares)Geobios151982783–789AlcoverJ.A.Els mamifers de les Balears1988Editorial MollPalma de Mallorca192AlcoverJ.A.Las faunas preneoliticas de las islas mediterraneasMundo Cientifico801988504–517AlcoverJ.A.LlabrésM.MoraguesL.L.(coord.).Les Balears abans dels humans. Monografies de la Societat d’Història Natural de les Balears 82000Sa Nostra-Societat d’Història Natural de les BalearsPalma de Mallorca78 pAlcoverJ.A.Moyà-SolàS.Pons-MoyàJ.Les quimeres del passat. Els vertebrats fossils del Plio-Quaternari de les Balears i Pitiüses. Monografies cientifiques 11981Editorial MollPalma de Mallorca260 pAlcoverJ.A.Perez-ObiolR.YllE.I.BoverP.The diet of Myotragus balearicus Bate, 1909 (Artiodactyla: Caprinae), an extinct bovid from the Balearic Islands: evidence from coprolitesBiol. J. Linn. Soc.66199957–72AzzaroliA.Il significato delle faune insulari quaternarieLe Scienze30197184–93BateD.M.A.A new artiodactyle from MajorcaGeol. Mag.61909385–388BateD.M.A.On a new genus of extinct murcardine rodent from the Balearic IslandsProc. Zool. Soc. Lond.1918209–222BateD.M.A.Pleistocene shrews from the larger western Mediterranean islandsAnn. Mag. Nat. Hist.111944738–769BauzàJ.Paleontología de Mallorca. Ciento ochenta millones de años de la flora y fauna de Mallorca. In: Mascaró-Pasarius, J. (Coord.)1971Historia de MallorcaPalma de Mallorca331–430BiewenerA.A.Biomechanics of mammalian terrestrial locomotionScience25019901097–1103BouJ.Contribució al coneixement de la biomecànica de la locomociò als micromamífers. PhD Thesis1988Universitat de BarcelonaSpainBouJ.CasinosA.OcañaJ.Allometry of the limb long bones of insectivores and rodentsJ. Morphol.1921987113–123BoverP.FornósJ.J.AlcoverJ.A.Carpal bones, carpal fusions and footprints of Myotragus: clues for locomotion and behavior. In: Alcover, J.A., Bover, P. (Eds.), Proceedings of the International Symposium “Insular Vertebrate Evolution: the Palaeontological Approach”Monogr. Soc. Hist. Nat. Balears12200559–72BoverP.AlcoverJ.A.MichauxJ.J.HautierL.HuttererR.Body shape and life style of the extinct balearic dormouse Hypnomys (Rodentia, Gliridae): new evidence from the study of associated skeletonsPLoS One520101–11ColomG.Biogeografía de las Baleares. La formación de las islas y el origen de su flora y fauna. Diputación Provincial de Baleares1978Instituto de Estudios Baleáricos y Consejo Superior de Investigaciones CientificasPalma de Mallorca515García-MartínezR.Marín-MoratallaN.JordanaX.KöhlerM.First results from bone histology of the giant fossil dormouse HypnomysKöhlerM.JordanaX.Marín-MoratallaN.Book of Abstracts of the First International Symposium on Paleohistology2011Institut Català de Paleontología Miquel CrusafontSabadell (Barcelona)78HildebrandM.Walking and runningHildebrandM.BrambleD.M.LiemK.F.WakeD.B.Functional Vertebrate Morphology1985The Belknap Press of Harvard University PressCambridge, MA, USA430HopkinsS.S.B.Reassessing the mass of exceptionally large rodents using tooth row length and area as proxies for body massJ. Mammal.892008232–243JordanaX.Marín-MoratallaN.DeMiguelD.KaiserT.M.KöhlerM.Evidence of correlated evolution of hypsodonty and exceptional longevity in endemic insular mammalsProc. Roy. Soc.27920123339–3346KöhlerM.Fast or slow? The evolution of life history traits associated with insular dwarfingPérez-MelladoV.RamonC.Islands and Evolution2010Institut Menorquí d’EstudisMaó (Menorca)261–280KöhlerM.Moyà-SolàS.Phalangeal adaptations in the fossil insular goat MyotragusJ. Vertebr. Paleontol.212001621–624KöhlerM.Moyà-SolàS.Reduction of brain and sense organs in the fossil insular bovid MyotragusBrain Behav. Evolut.632004125–140KöhlerM.Moyà-SolàS.Physiological and life history strategies of a fossil large mammal in a resource-limited environmentProc. Natl. Acad. Sci. U S A106200920354–20358LeindersJ.On the osteology and function of the digits of some rumiants and their bearing on taxonomySonderdruck aus Z. f. Säugetierkunde441979305–318LeindersJ.SondaarP.Y.On functional fusions in footbones of UngulatesSonderdruck aus Z. f. Säugetierkunde391974109–115López de HerediaU.JiménezP.Díaz-FrenándezP.GilL.Diversidad genética, origen y conservación de las especies esclérofilas del género Quercus en las Islas BalearesBoll. Soc. Hist. Nat. Balears48200543–60McNabB.K.Minimizing energy expenditure facilitates vertebrate persistence on oceanic islandsEcol. Lett.52002693–707MillsD.H.Osteological study of the Pleistocene dormouse Hypmomys morpheus Bate from Mallorca (Rodentia, Gliridae)Publ. Palaeontol. Inst. Univ. Uppsala419761–58MorenoS.Liron careto Elyomys quercinus (Linnaeus, 1776)Galemys1420021–16Moyá-SoláS.Morfología functional del tarso en el género Myotragus Bate, 1909 (Artiodactyla, Rupicaprini)Acta Geol. Hisp.133197987–91Moyà-SolàS.Pons-MoyàJ.Catálogo de los yacimientos con fauna de vertebrados del Plioceno, Pleistoceno y Holoceno de las BalearesEndins5197959–74Moyà-SolàS.Pons-MoyàJ.Una nueva especie del género Myotragus Bate, 1909 (Mammalia, Bovidae) en la isla de Menorca: Myotragus binigausensis nov. sp. Implicaciones paleozoogeográficasEndins7198037–47Pérez-ObiolR.YllE.I.Pataleón-CanoJ.RoureJ.M.Historia de Buxus y Corylus en las Islas Baleares durante el HolocenoRamil-RegoP.Fernández-RodríguezC.GüitiánM.Paleoambiente cuaternario en la Península Ibérica1996Santiago de CompostelaXunta de Galicia87–97QuintanaJ.Descripción de un rastro de Myotragus e icnitas de Hypnomys del yacimiento cuaternario de Ses Penyes d’es Perico (Ciutadella de Menorca, Balears)Paleontología i Evolució26–271993271–279QuintanaJ.Aproximación a los yacimientos de vertebrados del Mio-Pleistoceno de la isla de MenorcaBoll. Soc. Hist. Nat. Balears411998101–117QuintanaJ.Estudio morfologico y funcional de Nuralagus rex (Mammalia, Lagomorpha, leporidae). PhD Thesis2005Universitat Autònoma de BarcelonaSpainQuintanaJ.AgustíJ.Los mamíferos insulares del Mioceno medio y superior de Menorca (islas Baleares, Mediterráneo occidental)Geobios402007677–687QuintanaJ.ArnauP.Descripció dels rastres i les petjades d’Hypnomys Bate, 1918 (Mammalia: Gliridiae) de la cova de sa Duna (Alaior, Menorca)Endins2620047–14QuintanaJ.KöhlerM.Moyà-SolàS.Nuralagus rex, gen. et sp. nov., an endemic insular giant rabbit from the Neogene of Minorca (Balearic Islands, Spain)J. Vertebr. Paleontol.312011231–240SeguíB.Succesió estratigràfica d’aus en els rebliments càrstics de les Gymnèsies. PhD Thesis1998Universitat de les Illes BalearsSpainSondaarP.Y.Insularity and its effect on mammal evolutionHechtM.K.GoodyP.C.HechtB.M.Major Patterns in Vertebrate Evolution1977Plenum Publ. Co.671–707Van der GeerA.LyrasG.de VosJ.DermitzakisM.Evolution of Island Mammals. Adaptation and Extinction of Placental Mammals on Islands2010John Wiley & Sons, Ltd.Chichester479
Location of the studied deposits with Hypnomys spp. 1: Barranc de Binigaus (H. eliomyoides); 2: Sa Cigonya (Hypnomys sp.1); 3: deposit 17 from Punta Esquitxador (Hypnomys sp.2); 4: Sa Pedrera de s’Ònix (H. onicensis); 5: Sa Cova de sa Bassa Blanca (H. morpheus).
Localisation des dépôts à Hypnomys spp. étudiés. 1 : Barranc de Binigaus (H. eliomyoides) ; 2 : Sa Cigonya (Hypnomys sp.1) ; 3 : dépôt 17 de Punta Esquitxador (Hypnomys sp.2) ; 4 : Sa Pedrera de s’Ònix (H. onicensis) ; 5 : Sa Cova de sa Bassa Blanca (H. morpheus).
Measurements of the limbs’ long bones of Hypnomys spp. 1: functional length; 2: functional or sagittal diameter: taken at the halfway of the functional length or halfway between the articular surfaces of the proximal and distal epiphysis.
Mesures des os longs des extrémités d’Hypnomys spp. 1 : longueur fonctionnelle ; 2 : diamètre fonctionnel ou sagittal : distance moyenne entre les surfaces articulaires de l’épiphyse proximale et distale.
Graphic representations (axes in log 10 scale) of the diameter and length (log Y = log 0.8014 + 0.7429 log X) (below) and body mass in relation to the diameter (A) (log Y = log 0.0302 + 0.3944 log X) and length (B) (log Y = log 0.4080 + 0.3377 log X) (above) of the humerus of H. eliomyoides (circle), Hypnomys sp. from Sa Cigonya (black triangle), Hypnomys sp. from Punta Esquitxador (cross), H. onicensis from Sa Pedrera de s’Ònix (big inclined white square) and H. morpheus from Sa Cova de sa Bassa Blanca (small inclined black square). Eliomys quercinus (black circle).
Représentations graphiques (échelle des axes à log 10) des diamètre et longueur (log Y = log 0,8014 + 0,7429 log X) (en bas) et de la masse corporelle, en relation avec le diamètre (A) (log Y = log 0,0302 + 0,3944 log X) et la longueur (B) (log Y = log 0,4080 + 0,3377 log X) (en haut) de l’humérus d’H. eliomyoides (cercle), Hypnomys sp. de Sa Cigonya (triangle noir), Hypnomys sp. de Punta Esquitxador (croix), H. onicensis de Sa Pedrera de s’Ònix (grand carré blanc incliné) et H. morpheus de Sa Cova de sa Bassa Blanca (petit carré noir incliné). Eliomys quercinus (cercle noir).
After Bou (1988).
Graphic representations (axes in log 10 scale) of the diameter and length (log Y = log 0.8176 + 0.7477 log X) (below) and body mass in relation to the diameter (A) (log Y = log 0.0236 + 0.4646 log X) and length (B) (log Y = log 0.4814 + 0.2862 log X) (above) of the ulna of H. eliomyoides (circle), Hypnomys sp. from Punta Esquitxador (cross), H. onicensis from Sa Pedrera de s’Ònix (big inclined white square) and H. morpheus from Sa Cova de sa Bassa Blanca (small inclined black square). Eliomys quercinus (black circle).
Représentations graphiques (échelle des axes à log 10) des diamètre et longueur (log Y = log 0,8176 + 0,7477 log X) (en bas) et la masse corporelle, en relation avec le diamètre (A) (log Y = log 0,0236 + 0,4646 log X) et la longueur (B) (log Y = log 0,4814 + 0,2862 log X) (en haut) du cubitus d’H. eliomyoides (cercle), Hypnomys sp. de Punta Esquitxador (croix), H. onicensis de Sa Pedrera de s’Ònix (grand carré blanc incliné) et H. morpheus de Sa Cova de sa Bassa Blanca (petit carré noir incliné). Eliomys quercinus (cercle noir).
After Bou (1988).
Graphic representations (axes in log 10 scale) of the diameter and the length (log Y = log 0.9230 + 0.8279 log X) (below) and body mass in relation to the diameter (A) (log Y = log 0.0341 + 0.3847 log X) and length (B) (log Y = log 0.4491 + 0.3517 log X) (above) of the femur of H. eliomyoides (circle), Hypnomys sp. from Sa Cigonya (triangle), Hypnomys sp. from Punta Esquitxador (cross), H. onicensis from Sa Pedrera de s’Ònix (big inclined white square) and H. morpheus from Sa Cova de sa Bassa Blanca (small inclined black square). Eliomys quercinus (black circle).
Représentations graphiques (échelle des axes à log 10) des diamètre et longueur (log Y = log 0,9230 + 0,8279 log X) (en bas) et de la masse corporelle, en relation avec le diamètre (A) (log Y = log 0,0341 + 0,3847 log X) et la longueur (B) (log Y = log 0,4491 + 0,3517 log X) (en haut) du fémur d’H. eliomyoides (cercle), Hypnomys sp. de Sa Cigonya (triangle), Hypnomys sp. de Punta Esquitxador (croix), H. onicensis de Sa Pedrera de s’Ònix (grand carré blanc incliné) et H. morpheus de Sa Cova de sa Bassa Blanca (petit carré noir incliné). Eliomys quercinus (cercle noir).
After Bou (1988).
Graphic representations (axes in log 10 scale) of the diameter and length (log Y = log 0.9464 + 0.7145 log X) (below) and body mass in relation to the diameter (A) (log Y = log 0.0266 + 0.4268 log X) and length (B) (log Y = log 0.7969 + 0.2489 log X) (above) of the tibia of Hypnomys sp. from Sa Cigonya (black triangle), Hypnomys sp. from Punta Esquitxador (cross), H. onicensis from Sa Pedrera de s’Ònix (big inclined white square) and H. morpheus from Sa Cova de sa Bassa Blanca (small inclined black square). E. quercinus (black circle).
Représentations graphiques (échelle des axes à log 10) des diamètre et longueur (log Y = log 0,9464 + 0,7145 log X) (en bas) et de la masse corporelle, en relation avec le diamètre (A) (log Y = log 0,0266 + 0,4268 log X) et la longueur (B) (log Y = log 0,7969 + 0,2489 log X) (en haut) du tibia à Hypnomys sp. de Sa Cigonya (triangle noir), Hypnomys sp. de Punta Esquitxador (croix), H. onicensis de Sa Pedrera de s’Ònix (grand carré blanc incliné) et H. morpheus de Sa Cova de sa Bassa Blanca (petit carré noir incliné). Eliomys quercinus (cercle noir).
After Bou (1988).
Similarity percentages of locomotion types in Hypnomys spp. (vertical black bars) compared with Eliomys quercinus (vertical white bars). A. Jumping. B. Arboreal. C. Gliding. D. Fossorial. E. Swimming. F. Walking.
Pourcentages de similitude des types de locomotion chez Hypnomys spp. (barres noires verticales), en comparaison avec Eliomys quercinus (barres blanches verticales). A. Saut. B. Locomotion de type arboricole. C. Glisse. D. Creusement. E. Nage. F. Marche.
Body mass approximations for the five studied populations.
Approximations de la masse corporelle pour les cinq populations étudiées.