PREVALENCE AND PARASITE INTENSITY OF HAEMOGREGARINES IN AFRICAN BELL HINGE-BACK (KINIXYS BELLIANA) AND AFRICAN HOME'S HINGE-BACK (KINIXYS HOMEANA) TORTOISES IN IBADAN, NIGERIA

Haemogregarines are a group of intracellular blood parasites reported in reptiles, other vertebrate taxa including mammals and fish, and haematophagous invertebrates. Information on prevalence, biodiversity, and host-specificity of haemogregarines of tortoises in Nigeria are scarce. A total of 120 African hinge-back tortoises (Kinixys belliana, n=70, and K. homeana, n=50) were bought from the Wildlife and Herbal Market in Ibadan, Nigeria. Blood was withdrawn via the subcarapacial sinuses of each tortoise. The prevalence and parasite intensity of haemogregarine infection was determined using a light microscope, and parasite species were determined by PCR using HepF300 and HepR900 primers. A sequence of 654 base pairs (bp; Hepatozoon cf. fitzsimonsi) from the study aligned with published 18SrRNA and closely related with a similarity of 97.38% to Hepatozoon fitzsimonsi sequenced from Kinixys zobensis in South Africa. Overall prevalence of haemogregarines was 53.33% from light microcopy and 75.83% from PCR, which is considered very high. Higher prevalence and mean±SD parasite intensity were recorded for K. belliana (82.89%, 0.29%) than for K. homeana (66.00%, 0.26%). Prevalence rates and parasite intensities of haemogregarines were significantly higher in wet than in dry seasons. The differences in prevalence and intensity between and within species may be due to habitat characteristics, feeding habits of vectors and hosts, seasons, and vector abundance.

Skeletal repatterning enhances the protective capacity of the shell in African hinge-back tortoises (Kinixys)

Changes in the structural association of skeletal traits are crucial to the evolution of novel forms and functions. In vertebrates, such rearrangements often occur gradually and may precede or coincide with the functional activation of skeletal traits. To illustrate this process, we examined the ontogeny of African hinge-back tortoises (Kinixys spp.). Kinixys species feature a moveable "hinge" on the dorsal shell (carapace) that enables shell closure (kinesis) when the hind limbs are withdrawn. This hinge, however, is absent in juveniles. Herein, we describe how this unusual phenotype arises via alterations in the tissue configuration and shape of the carapace. The ontogenetic repatterning of osseous and keratinous tissue coincided with shifts in morphological integration and the establishment of anterior (static) and posterior (kinetic) carapacial modules. Based on ex vivo skeletal movement and raw anatomy, we propose that Kinixys employs a "sliding hinge" shell-closing system that overcomes thoracic rigidity and enhances the protective capacity of the carapace. Universal properties of the vertebrate skeleton, such as plasticity, modularity, and secondary maturation processes, contributed to adaptive evolutionary change in Kinixys. We discuss a hypothetical model to explain the delayed emergence of skeletal traits and its relevance to the origins of novel form-to-function relationships.

Genomic analyses reveal two species of the matamata (Testudines: Chelidae: Chelus spp.) and clarify their phylogeography

The matamata is one of the most charismatic turtles on earth, widely distributed in northern South America. Debates have occurred over whether or not there should be two subspecies or species recognized due to its geographic variation in morphology. Even though the matamata is universally known, its natural history, conservation status and biogeography are largely unexplored. In this study we examined the phylogeographic differentiation of the matamata based on three mitochondrial DNA fragments (2168 bp of the control region, cytochrome oxidase subunit I, and the cytochrome b gene), one nuclear genomic DNA fragment (1068 bp of the R35 intron) and 1661 Single Nucleotide Polymorphisms (SNPs). Our molecular and morphological analyses revealed the existence of two distinct, genetically deeply divergent evolutionary lineages of matamatas that separated in the late Miocene (approximately 12.7 million years ago), corresponding well to the time when the Orinoco Basin was established. As a result of our analyses, we describe the genetically and morphologically highly distinct matamata from the Orinoco and Río Negro Basins and the Essequibo drainage as a species new to science (Chelus orinocensis sp. nov.). Chelus fimbriata sensu stricto is distributed in the Amazon Basin and the Mahury drainage. Additionally, the analyses revealed that each species displays phylogeographic differentiation. For C. orinocensis, there is moderate mitochondrial differentiation between the Orinoco and the Río Negro. For C. fimbriata, there is more pronounced differentiation matching different river systems. One mitochondrial clade was identified from the Amazon, Ucayali, and Mahury Rivers, and another one from the Madeira and Jaci Paraná Rivers. The C. orinocensis in the Essequibo and Branco Rivers have haplotypes that constitute a third clade clustering with C. fimbriata. Phylogenetic analyses of the R35 intron and SNP data link the matamatas from the Essequibo and Branco with the new species, suggesting past gene flow and old mitochondrial introgression. Chelus orinocensis is collected for the pet trade in Colombia and Venezuela. However, neither the extent of the harvest nor its impact are known. Hence, it is crucial to gather more information and to assess its exploitation throughout its distribution range to obtain a better understanding of its conservation status and to design appropriate conservation and management procedures. RESUMEN: La matamata es una de las tortugas más carismáticas del mundo, ampliamente distribuida en el norte de Sudamérica. Debido a su variación morfológica geográfica, se debate sobre el reconocimiento de dos subespecies o especies. A pesar de que la matamata es universalmente conocida, su historia natural, estado de conservación y biogeografía han sido muy poco estudiados. En este estudio examinamos la diferenciación filogeográfica de las matamatas en base ​​a tres fragmentos de ADN mitocondrial (2168 pb de la región de control, la subunidad I del citocromo oxidasa y el gen del citocromo b), un fragmento de ADN genómico nuclear (1068 pb del intrón R35) y 1661 polimorfismos de nucleótido único (SNPs). Nuestros análisis moleculares y morfológicos revelaron la existencia de dos linajes evolutivos distintos de matamatas, genéticamente divergentes que se separaron en el Mioceno tardio (hace aproximadamente 12.7 millones de años), correspondiendo al tiempo en que se estableció la cuenca del Orinoco. Como resultado de nuestros análisis, describimos las genéticamente y morfológicamente distintas matamatas de las cuencas del Orinoco, Río Negro y Essequibo como una especie nueva para la ciencia (Chelus orinocensis sp. nov.). Chelus fimbriata sensu stricto se distribuye en la cuenca del Amazonas y en el drenaje del Mahury. Adicionalmente, los análisis revelaron que cada especie muestra diferenciación filogeográfica. Para C. orinocensis, hay una moderada diferenciación mitocondrial entre el Orinoco y el Río Negro. Para C. fimbriata, hay una diferenciación más pronunciada, concordando con los diferentes sistemas fluviales. Se identificó un clado de los ríos Amazonas, Ucayali y Mahury y otro de los ríos Madeira y Jaci Paraná. Las C. orinocensis de los ríos Essequibo y Branco tienen haplotipos que constituyen un tercer clado que se agrupa con C. fimbriata. Los análisis filogenéticos del intrón R35 y los datos de SNP asocian las matamatas de Essequibo y Branco con la nueva especie, sugiriendo flujo de genes pasado ​​e introgresión mitocondrial antigua. Chelus orinocensis se colecta para el comercio de mascotas en Colombia y Venezuela. Sin embargo, ni se conoce el alcance de las colectas ni su impacto. Por lo tanto, es crucial recopilar más información y evaluar su explotación en todo su rango de distribución, comprender mejor su estado de conservación y para diseñar acciones apropiadas de conservación y manejo.

Total evidence analysis and body size evolution of extant and extinct tortoises (Testudines: Cryptodira: Pan-Testudinidae)

Testudinidae (tortoises) is an extant clade of terrestrial turtles of worldwide distribution and with a rich fossil record that provides an exceptional context for studying their evolutionary history. Because of the lack of global phylogenetic analyses integrating extinct taxa, our current knowledge of the relationships of the total clade of Testudinidae is rather poor. To resolve this issue, we performed the first total evidence analysis of Pan-Testudinidae. The total evidence trees are congruent with the molecular topology and agree on the dichotomy of derived Testudinidae (=Testudininae; Converted Clade Name) into two previously recognized major clades, Testudona and Geochelona (New Clade Name). The integration of extinct taxa into the analysis allowed the stratigraphic fit of the total evidence trees, indicating that crown Testudininae, Testudona and Geochelona all originated by the Late Eocene, in agreement with recent molecular estimates. Ghost lineage analysis indicates high diversification in the Late Eocene and in the Miocene. The age of crown Testudo is Late Miocene, again in accordance with some molecular dates. Phylogenetic placement of fossils demonstrates that giant body size independently evolved in multiple continental mainland taxa and confirms recent results deduced from living taxa-giantism in Testudinidae is not linked to the insular effect. An unexpected outcome is the recovery of miniaturization in Testudona (<30 cm carapace length) that emerged sometime between the Oligocene and Early Miocene. No clear correlation between body size evolution and climate is apparent, but increased taxon sampling may nevertheless demonstrate the role of cooling and warming as one of many influential variables.

One extinct turtle species less: Pelusios seychellensis is not extinct, it never existed

Pelusios seychellensis is thought to be a freshwater turtle species endemic to the island of Mahé, Seychelles. There are only three museum specimens from the late 19(th) century known. The species has been never found again, despite intensive searches on Mahé. Therefore, P. seychellensis has been declared as "Extinct" by the IUCN and is the sole putatively extinct freshwater turtle species. Using DNA sequences of three mitochondrial genes of the historical type specimen and phylogenetic analyses including all other species of the genus, we provide evidence that the description of P. seychellensis was erroneously based on a widely distributed West African species, P. castaneus. Consequently, we synonymize the two species and delete P. seychellensis from the list of extinct chelonian species and from the faunal list of the Seychelles.

Weak genetic divergence between the two South American toad-headed turtles Mesoclemmys dahli and M. zuliae (Testudines: Pleurodira: Chelidae)

Mesoclemmys dahli and M. zuliae are two endangered, little-known toad-headed turtles with small distribution ranges in Colombia and Venezuela, respectively. Using the mitochondrial cytochrome b gene as a marker, we investigate their phylogeographic differentiation. Furthermore, based on 2341 bp of mtDNA and 2109 bp of nDNA of M. dahli, M. zuliae and allied chelid turtles, we infer their divergence time using a fossil-calibrated relaxed molecular clock approach. Mesoclemmys dahli and M. zuliae are closely related species, with an estimated mean divergence time of 10.6 million years. This estimate correlates with the uplift of the Serranía de Perijá, an Andean mountain chain separating their distribution ranges, suggesting that this event could have caused the evolution of the two species. Haplotype and nucleotide diversities of M. dahli are markedly higher than in Podocnemis lewyana, another endemic turtle species of Colombia. This pronounced dissimilarity may reflect differences in the phylogeographies and demographic histories of the two species, but also different habitat preferences.