Evolutionary history of the extinct Sardinian dhole

Ancient DNA re-opens the question of the phylogenetic position of the Sardinian pika Prolagus sardus (Wagner, 1829), an extinct lagomorph

Palaeogenomics is contributing to refine our understanding of many major evolutionary events at an unprecedented resolution, with relevant impacts in several fields, including phylogenetics of extinct species. Few extant and extinct animal species from Mediterranean regions have been characterised at the DNA level thus far. The Sardinian pika, Prolagus sardus (Wagner, 1829), was an iconic lagomorph species that populated Sardinia and Corsica and became extinct during the Holocene. There is a certain scientific debate on the phylogenetic assignment of the extinct genus Prolagus to the family Ochotonidae (one of the only two extant families of the order Lagomorpha) or to a separated family Prolagidae, or to the subfamily Prolaginae within the family Ochotonidae. In this study, we successfully reconstructed a portion of the mitogenome of a Sardinian pika dated to the Neolithic period and recovered from the Cabaddaris cave, an archaeological site in Sardinia. Our calibrated phylogeny may support the hypothesis that the genus Prolagus is an independent sister group to the family Ochotonidae that diverged from the Ochotona genus lineage about 30 million years ago. These results may contribute to refine the phylogenetic interpretation of the morphological peculiarities of the Prolagus genus already described by palaeontological studies.

The extinct Sicilian wolf shows a complex history of isolation and admixture with ancient dogs

The Sicilian wolf remained isolated in Sicily from the end of the Pleistocene until its extermination in the 1930s-1960s. Given its long-term isolation on the island and distinctive morphology, the genetic origin of the Sicilian wolf remains debated. We sequenced four nuclear genomes and five mitogenomes from the seven existing museum specimens to investigate the Sicilian wolf ancestry, relationships with extant and extinct wolves and dogs, and diversity. Our results show that the Sicilian wolf is most closely related to the Italian wolf but carries ancestry from a lineage related to European Eneolithic and Bronze Age dogs. The average nucleotide diversity of the Sicilian wolf was half of the Italian wolf, with 37-50% of its genome contained in runs of homozygosity. Overall, we show that, by the time it went extinct, the Sicilian wolf had high inbreeding and low-genetic diversity, consistent with a population in an insular environment.

The earliest Ethiopian wolf: implications for the species evolution and its future survival

In 2017, a hemimandible (MW5-B208), corresponding to the Ethiopian wolf (Canis simensis), was found in a stratigraphically-controlled and radio-isotopically-dated sequence of the Melka Wakena paleoanthropological site-complex, on the Southeastern Ethiopian Highlands, ~ 2300 m above sea level. The specimen is the first and unique Pleistocene fossil of this species. Our data provide an unambiguous minimum age of 1.6-1.4 Ma for the species' presence in Africa and constitutes the first empirical evidence that supports molecular interpretations. Currently, C. simensis is one of the most endangered carnivore species of Africa. Bioclimate niche modeling applied to the time frame indicated by the fossil suggests that the lineage of the Ethiopian wolf faced severe survival challenges in the past, with consecutive drastic geographic range contractions during warmer periods. These models help to describe future scenarios for the survival of the species. Projections ranging from most pessimistic to most optimistic future climatic scenarios indicate significant reduction of the already-deteriorating territories suitable for the Ethiopian Wolf, increasing the threat to the specie's future survival. Additionally, the recovery of the Melka Wakena fossil underscores the importance of work outside the East African Rift System in research of early human origins and associated biodiversity on the African continent.

Museomics Provides Insights into Conservation and Education: The Instance of an African Lion Specimen from the Museum of Zoology “Pietro Doderlein”

Innovative technological approaches are crucial to enhance naturalistic museum collections and develop information repositories of relevant interest to science, such as threatened animal taxa. In this context, museomics is an emerging discipline that provides a novel approach to the enhancement and exploitation of these collections. In the present study, the discovery of a neglected lion skeleton in the Museum of Zoology “Pietro Doderlein” of the University of Palermo (Italy) offered the opportunity to undertake a multidisciplinary project. The aims of the study consisted of the following: (i) adding useful information for museographic strategies, (ii) obtaining a new genetic data repository from a vulnerable species, (iii) strengthening public awareness of wildlife conservation, and (iv) sharing new learning material. The remains of the lion were examined with a preliminary osteological survey, then they were restored by means of 3D printing of missing skeletal fragments. Phylogenetic analyses based on cytochrome b sequence clearly indicate that the specimen belongs to the Central Africa mitochondrial clade. At the end of the study, the complete and restored skeleton was exhibited, along with all of the information and data available from this project. This study shows a useful approach for the restoration and enhancement of a museum specimen, with important opportunities for preserving biodiversity and driving specific conservation policies, but also for providing Life Science learning material.

First Attempt to Infer Sound Hearing and Its Paleoenvironmental Implications in the Extinct Insular Canid Cynotherium sardous Studiati, 1857 (Sardinia, Italy)

Simple Summary

The microtomographic approach allows nondestructive acquisition of anatomical details of the bone labyrinth that houses the inner ear. The petrosal bone can be a gold mine of information for a variety of questions in different research fields, including taxonomic, behavioral, and genetic studies. The semicircular canals provide information on head posture and locomotor ability, whereas the cochlea provides data on hearing ability. The petrosal bone is the hardest structure in the skeleton and could be well preserved in fossil specimens. As a result, it is becoming more and more popular in current archaeological and paleontological studies. In this study, petrosal microtomographic analysis was applied for the first time to Cynotherium sardous, a highly modified endemic canid that inhabited Sardinia during the Middle to Late Pleistocene. Indications about its hearing ability may provide interesting insights to better understand the new lifestyle and behavior this canid acquired during the long evolutionary process it underwent in the peculiar insular ecosystem with a depleted fauna. The poor hearing and echolocalization capabilities of Cynotherium sardous would have been the outcome of reduced competition pressure due to the absence of predators and the abundance of prey, such as the large ochotonid Prolagus sardus, while the high-frequency hearing could be interpreted as an adaptation to detect sounds emitted by its preferred prey.

Abstract

This is the first study on the bony labyrinth of Cynotherium sardous, an intriguing extinct canid that inhabited Sardinia in the late Middle and Late Pleistocene. The morphological features of the cochlea indicate that C. sardous had a lower number of cochlear turns (2.25) than all extant canids. This feature, as well as the reduced length of the spiral canal, the cochlear curvature rate, and the narrow basal membrane, indicates that C. sardous had poor hearing abilities limited to high-frequency sounds with a low limit of 250 Hz and poor echolocalization skills. From the data available, it is not possible to infer whether C. sardous was unable to echolocalize its prey and relied on other senses (e.g., smell and sight) to locate them or whether the acoustic range of C. sardous was specialized for identifying the sounds produced by its most common prey to transmit signals for predator warnings or group communication. All things considered, the results obtained confirm the utility of cochlea morphological studies in reconstructing the hearing abilities of this species and in providing some suggestions about its ethology, but they fall short of providing any new sound evidence regarding the ecological role of C. sardous in the Late Pleistocene Sardinian ecosystem.