The mounting of a skeleton of the fossil species Candiaceruus sp. II from Liko Cave, Crete, Greece

S'ha muntat un esquelet del cérvol pleistocènic endèmic de Creta per a la nova exhibició del Museu de Geologia de la Universitat d'Atenes. Aquest cérvol difereix de tots els cérvols continentals vivents i extingits, principalment en les seves proporcions. Les mesures i comparacions confirmen aquesta observació, però això no és prou com per a que el públic general se n'adoni del seu impacte. Per contra, un esquelet muntat deixa clar que aquest cérvol tertia uns membres considerablement escurçats, especialment els metàpodes, mentre que la llargària del cos, a la llargària de la columna vertebral, eren més aviat normals. La impressió global és més propera a la d'un bòvid nan insular, com ara Myotragus, que a la d'un cérvol petit, tal com Axis axis. El primer problema a resoldre fou la selecció de material. Ja que mai s'ha trobat un esquelet articulat complet, se n'ha de fer un de compost. Amb aquest motiu, només es varen seleccionar ossos de la classe de talla II (de Vos, 1979 ; Dermitzakis & de Vos, 1987) provinents d'un nivell d'una cova (cova de Liko, estrat B). D'aquesta manera es garanteix un interval geològic estret. Tot seguit, es varen mesurar tots els espècimens disponibles, i es va calcular el promig per a tots els elements. D'acord amb això, es va triar l'exemplar de cada element que més s'apropava a la mitjana calculada. Les peces dretes i esquerres havien de ser de la mateixa mida i robustesa, i els elements contigus havien de casar anatòmicament. Només en alguns casos s'ha hagut de recórrer a triar algun element que faltava a partir d'un llivell diferent, però mai a partir d'una cova diferent i mai a partir d'una classe de talla diferent. S'ha prioritzat la mida, la robustesa i l'ajustament anatòmic, i després que els ossos fossin complets i el color. Hi havia alguns peus articulats disponibles, encara que de mida i robustesa diferents, que s'han emprat per determinar les proporcions correctes i la posició correcta entre les falanges individuals, i els ossos carpians i tarsians. La mateixa cosa fou vàlida per a la columna vertebral. Per a l'establiment de la postura es van fer servir cérvols vivents com a comparació; per a l'extrapolació dels teixits tous (discos intervertebrals, cartílags de les articulacions) també es va recórrer al model dels cérvols vivents. De cara a amagar els bastiments de suport, es va inserir dins els ossos una armadura metàl-lica interna fent forats i fitxant-la amb goma de poliuretà. S'ha fabricat l'esquelet complet en parts modulars bones d'ajuntar pel seu transport fàcil a la mostra. Parts absents petites (principalment processos vertebrals, parts costals i les ales pèlviques) s'han reconstruït amb apoxy, en base a altres elements disponibles de Candiacervus de la cova de Liko a per interpolació del millor ajustament entre dues parts absents. Les traces de la matriu original han estat estretes, per a una impressió millor del material fòssil. Per completar l'esquelet s'ha fet una rèplica del crani de l'espècimen tipus de la classe de talla II de de Vos (1979) i una rèplica de l'espècimen tipus del banyam tipus I de de Vos (1984).For the new exhibition in the Museum of Palaeontology and Geology of the University of Athens a skeleton of the endemic Pleistocene Cretan deer was mounted. This deer differs from all known recent and extinct mainland deer, mainly in its proportions. Measurements and comparisons confirm this observation, but are not enough to make the public realize its impact. A mounted skeleton on the contrary makes it at once clear that this deer had considerably shortened limbs, especially the metapodals, whereas the body length and the vertebral column length are rather normal. The overall impression is closer to that of an insular dwarf bovid like Myotragus than to that of a small deer such as the spotted deer (Axis axis). The first problem to be tackled was the selection of the material. Since a complete articulated skeleton has never been found, a composite had to be made. For this purpose, only bones of size class II (de Vas, 1979; Dermitzakis & de Vas, 1987) coming from one layer of one cave (Liko Cave, layer El were selected. In this way a narrow geological range was assured. Subsequently, tile available specimens were measured, and of all elements the average size was calculated. Accordingly, of each element tile specimen that came tile most close to tile calculated average was selected. Left and right had to be of exactly the same size and robustness, and adjoining elements had to fit anatornically. Only in some cases a missing element had to be chosen from a different layer (layers C and Dl. but never from a different cave, and never from a different size class. Priority was first given to size, robustness and anatomical fitting, and next to completeness and colour. Several articulated feet were available, although of tile wrong size or robustness, which were used in determining the right proportions and right stance between individual phalanges, tarsal and carpal bones. The same was valid for tile vertebral column. For postural aspects, living deer were used as comparison; for extrapolation of soft tissue (intervertebral disks, articulation cartilage) also living deer stood model. In order to keep the supporting fabrication as hidden as possible, an internal metal armature was inserted in tile bones through drilled holes and fixed with polyurethane glue. The complete skeleton is fabricated in ready-to-assemble modular parts for easy transportation and reassembly on the spot. Minor missing parts (mainly vertebral processes, costal parts and tile pelvic wings) have been reconst: ructed in epoxy putty, based on other Candiaceruus elements from Liko or by interpolating the best fit between two existing parts. For a better impression of the fossil material, traces of tile original matrix were left on the bones. A cast of the skull of the type specimen of size II of de Vas (1979) and a cast of tile type specimen of antler type 1 of de Vas (1984) were made to complete the skeleton

A dwarf elephant and a rock mouse on Naxos (Cyclades, Greece) with a revision of the palaeozoogeography of the Cycladic Islands (Greece)during the Pleistocene

During the Late Pleistocene, Naxos and adjacent areas, including Delos and Paros, constituted a mega-island, here referred to as palaeo-Cyclades. The extensive low-lying plainswith lakes and rivers provided a suitable habitat for elephants. Due to long-term isolation from the mainland and mainland populations, these elephants evolved miniature size. The species found on Naxos had a body size of about ten percent of that of the mainland ancestor, Palaeoloxodon antiquus. During the glacial periods of the Late Pleistocene, P. antiquus may have migrated eastwards and southwards in search of better conditions and reached the islands. The dwarf species of the various Southern Aegean islands (e.g. Crete, Tilos, Rhodos, palaeo-Cyclades) are each the result of independent colonisation events. The very small size of the Naxos species respective to the dwarf elephants from Crete is explained as due to the lack of competitors. The only other elements of the contemporaneous fauna were a rock mouse (Apodemus cf. mystacinus) and a shrew (Crocidura sp.). Submergence of the area, climate change, volcanism, hunting by humans or a combination of these factors during the terminal Pleistocene may have caused the extinction of this endemic fauna

The effect of area and isolation on insular dwarf proboscideans

Aim We investigated the hypothesis that insular body size of fossil elephants is directly related to isolation and surface area of the focal islands. Location Palaeo-islands worldwide. Methods We assembled data on the geographical characteristics (area and isolation) of islands and body size evolution of palaeo-insular species for 22 insular species of fossil elephants across 17 islands. Results Our results support the generality of the island rule in the sense that all but one of the elephants experienced dwarfism on islands. The smallest islands generally harbour the smallest elephants. We found no support for the hypothesis that body size of elephants declines with island isolation. Body size is weakly and positively correlated with island area for proboscideans as a whole, but more strongly correlated for Stegodontidae when considered separately. Average body size decrease is much higher when competitors are present. Main conclusions Body size in insular elephants is not significantly correlated with the isolation of an island. Surface area, however, is a significant predictor of body size. The correlation is positive but relatively weak; c. 23% of the variation is explained by surface area. Body size variation seems most strongly influenced by ecological interactions with competitors, possibly followed by time in isolation. Elephants exhibited far more extreme cases of dwarfism than extant insular mammals, which is consistent with the substantially more extended period of deep geological time that the selective pressures could act on these insular populations

Dwarf deer of Crete.

26 pages : illustrations (some color), map ; 26 cm.Age-graded fossils of Pleistocene endemic Cretan deer (Candiacervus spp.) reveal unexpectedly high juvenile mortality similar to that reported for extant mainland ruminants, despite the fact that these deer lived in a predator-free environment and became extinct before any plausible date for human arrival. Age profiles show that deer surviving past the fawn stage were relatively long-lived for ruminants, indicating that high juvenile mortality was not an expression of their living a "fast" life. Although the effects on survivorship of such variables as fatal accidents, starvation, and disease are difficult to gauge in extinct taxa, the presence of extreme morphological variability within nominal species/ecomorphs of Candiacervus is consistent with the view that high juvenile mortality can function as a key innovation permitting rapid adaptation in insular contexts

Of mice and mammoths: generality and antiquity of the island rule

ABSTRACT Aim We assessed the generality of the island rule in a database comprising 1593 populations of insular mammals (439 species, including 63 species of fossil mammals), and tested whether observed patterns differed among taxonomic and functional groups. Location Islands world-wide. Methods We measured museum specimens (fossil mammals) and reviewed the literature to compile a database of insular animal body size (S i = mean mass of individuals from an insular population divided by that of individuals from an ancestral or mainland population, M). We used linear regressions to investigate the relationship between S i and M, and ANCOVA to compare trends among taxonomic and functional groups. Results S i was significantly and negatively related to the mass of the ancestral or mainland population across all mammals and within all orders of extant mammals analysed, and across palaeo-insular (considered separately) mammals as well. Insular body size was significantly smaller for bats and insectivores than for the other orders studied here, but significantly larger for mammals that utilized aquatic prey than for those restricted to terrestrial prey. Main conclusions The island rule appears to be a pervasive pattern, exhibited by mammals from a broad range of orders, functional groups and time periods. There remains, however, much scatter about the general trend; this residual variation may be highly informative as it appears consistent with differences among species, islands and environmental characteristics hypothesized to influence body size evolution in general. The more pronounced gigantism and dwarfism of palaeo-insular mammals, in particular, is consistent with a hypothesis that emphasizes the importance of ecological interactions (time in isolation from mammalian predators and competitors was 0.1 to > 1.0 Myr for palaeo-insular mammals, but < 0.01 Myr for extant populations of insular mammals). While ecological displacement may be a major force driving diversification in body size in high-diversity biotas, ecological release in species-poor biotas often results in the convergence of insular mammals on the size of intermediate but absent species