Ecological specialization, rather than the island effect, explains morphological diversification in an ancient radiation of geckos

Island colonists are often assumed to experience higher levels of phenotypic diversification than continental taxa. However, empirical evidence has uncovered exceptions to this ‘island effect’. Here, we tested this pattern using the geckos of the genus Pristurus from continental Arabia and Africa and the Socotra Archipelago. Using a recently published phylogeny and an extensive morphological dataset, we explore the differences in phenotypic evolution between Socotran and continental taxa. Moreover, we reconstructed ancestral habitat occupancy to examine if ecological specialization is correlated with morphological change, comparing phenotypic disparity and trait evolution between habitats. We found a heterogeneous outcome of island colonization. Namely, only one of the three colonization events resulted in a body size increase. However, in general, Socotran species do not present higher levels or rates of morphological diversification than continental groups. Instead, habitat specialization explains better the body size and shape evolution in Pristurus . Particularly, the colonization of ground habitats appears as the main driver of morphological change, producing the highest disparity and evolutionary rates. Additionally, arboreal species show very similar body size and head proportions. These results reveal a determinant role of ecological mechanisms in morphological evolution and corroborate the complexity of ecomorphological dynamics in continent–island systems.

Landscape habitat occupancy and distribution of the Wild Ground Pangolin (Smutsia temminckii) in Zimbabwe’s Protected Areas (PAs)

The Smutsia temminckii is the only species of pangolin known to exist in Zimbabwe and is considered vulnerable under the IUCN Red List of threatened species. Distribution of wild S. temminckii in protected areas (PAs) and associated environmental variables are not well defined in Zimbabwe. The study sort to relate key environmental variables (Altitude, rainfall, temperature and vegetation type) to habitat occupancy and distribution of S. temminckii. Data was collected from forty-eight stations based on S.temminckii sightings historical records spanning ten years (2011-2021) done by field rangers, tourists and scientific services research personnel. A review of available literature was done from online sources and station records. A distribution map based on S. temminckii sightings across various PAs in Zimbabwe was developed for this study. Results of this study reveal that S. temminckii occupy PAs in South East low-veld areas, Northwestern Zimbabwe, Mid Zambezi Valley and Nyanga NP. No historical data on S. temminckii sighting in central PAs located in ecological regions IIa, IIb and III of Zimbabwe. Climatic conditions associated with S. temminckii distribution, except for Nyanga NP, are average temperatures above 220C and rainfall between 400mm to 900mm per annum. Landscapes ideal for S. temminckii habitat occupancy have an altitude between 262m-2000m above sea level. Associated vegetation types for habitat occupancy of S. temminckii are the Zambezian and mopane woodlands as well as montane forest grasslands mosaic of Nyanga NP. Future studies should focus on establishing distribution of S. temminckii outside PA, population status and density to inform conservation of this rare and unique species around Zimbabwe.

Hard times for catadromous fish: the case of the European eel (Anguilla anguilla, L. 1758)

Catadromous fish species are very important organisms for their ecological, economical, and cultural value. For its complex life species catadromous fish result in worldwide decline since the beginning of the 20th century. Among the most iconic catadromous species, the European eel Anguilla anguilla L. 1758 has aroused considerable interest since very ancient times. Because, to date, many aspects of their life cycle remain relatively unknown, to implement our knowledge about the main natural and anthropogenic threats to its survivorship and identify possible solutions to preserve it, in this narrative review, we present the state of the knowledge about the life cycle, habitat occupancy, recruitment, and migration patterns of the European eel and about the major threats most likely have contributed to the decline of eels’ populations.

Distal Humeral Morphology Indicates Locomotory Divergence in Extinct Giant Kangaroos

Previous studies of the morphology of the humerus in kangaroos showed that the shape of the proximal humerus could distinguish between arboreal and terrestrial taxa among living mammals, and that the extinct “giant” kangaroos (members of the extinct subfamily Sthenurinae and the extinct macropodine genus Protemnodon) had divergent humeral anatomies from extant kangaroos. Here, we use 2D geometric morphometrics to capture the shape of the distal humerus in a range of extant and extinct marsupials and obtain similar results: sthenurines have humeral morphologies more similar to arboreal mammals, while large Protemnodon species (P. brehus and P. anak) have humeral morphologies more similar to terrestrial quadrupedal mammals. Our results provide further evidence for prior hypotheses: that sthenurines did not employ a locomotor mode that involved loading the forelimbs (likely employing bipedal striding as an alternative to quadrupedal or pentapedal locomotion at slow gaits), and that large Protemnodon species were more reliant on quadrupedal locomotion than their extant relatives. This greater diversity of locomotor modes among large Pleistocene kangaroos echoes studies that show a greater diversity in other aspects of ecology, such as diet and habitat occupancy.

Habitat Occupancy by Spruce Grouse (Canachites canadensis) in the south of its range, Québec, Canada

Studying habitat occupancy at the margins of species’ distributions can be helpful in clarifying species’ requirements and planning management measures. Spruce grouse (Canachites canadensis Linnaeus, 1758), a bird species associated with northern short-needle coniferous forests in North America, has its southeastern range limit where coniferous forests are mixed with temperate deciduous forests and agricultural lands. Some isolated populations are found in these habitats. Using a single-season occupancy modelling approach, we investigated habitat use by spruce grouse, accounting for imperfect detection, in the lowlands of the St. Lawrence River in southern Québec, Canada. We conducted call-response spruce over three years at 279 sites (59 sites in 2007, 100 sites in 2008 and 120 sites in 2009). At the site level, the probability of occupancy was 21% (IC: 10.7% - 37.9%) and probability of detection was 54% (IC: 34.7% - 73.0%). Based on the covariates in the models, occurrence increased with higher cover of coniferous trees and low deciduous shrubs, and decreased with higher cover of deciduous trees. Finally, detection probability was highest at the beginning of the survey (50% in late April) and was influenced by year.

Flesh fly (Diptera: Sarcophagidae): male terminalia, diversity and expanded geographical distribution from India

Despite its veterinary, medical and forensic importance, the biodiversity of sarcophagid flies (Diptera: Sarcophagidae) has remained poorly investigated in India. We have performed a survey of Sarcophagidae species in connection with a study conducted on Diptera, which exposed the flesh fly diversity in and around the campus of the University of Calicut, Kerala, India. The survey was conducted using traps baited with decomposing fish and chicken liver and by the sweeping method. Eleven species were collected, including four species recorded from this state for the first time, one of which is new to the Indian mainland and the second record after Sundarbans Biosphere Reserve. Male terminalia of Sinonipponia bengalensis, Parasarcophaga choudhuryi, Boettcherisca karnyi, and Boettcherisca nathani are illustrated. This result expands the knowledge on the geographical distribution and habitat occupancy of sarcophagid species as well as their forensic relevance and provides a background for future systematic investigations.

Habitat occupancy of sloth bear Melursus ursinus in Chitwan National Park, Nepal

Mammals around the world face serious threats and experience massive decline in their populations and geographic ranges. The sloth bear has become extinct from two of five range countries and the existing population face serious conservation threats. Despite being endangered in Nepal, decades of conservation obliviousness have hindered their conservation and management. We assessed the distribution and habitat use by sloth bears in relation to landscape, environmental, and anthropogenic factors in Chitwan National Park, Nepal. We conducted a sign survey from March-June 2020 in 4*4 km2 grids (n=45) in a checkerboard approach. An observation was spatially replicated four times by recording information in four continuous search trails of 1 km each. We recorded presence/absence of sloth bears, termites, fruits and disturbance in the field and extracted information on tree cover, terrain ruggedness and vegetation index from remotely sensed image of the study area. The data was analyzed using single species-single season occupancy method in PRESENCE software. By using repeated observations these models account for imperfect detectability of species to provide robust estimates of species occupancy. Averaged habitat occupancy estimate obtained from the best models was Ѱ = 0.53 ± 0.04SE with detection probability p = 0.44 ± 0.1SE. Selection of variable based on summed AIC weight from the top models (AIC<2) showed that presence of termites (ƩWi=0.66) significantly influenced sloth bear habitat occupancy. Habitat occupancy was positively influenced by termites followed by fruits, disturbance, terrain ruggedness and vegetation productivity, whereas, it was negatively influenced by tree cover. We suggest that future conservation interventions and action plans aimed at sloth bear management must adequately consider these requirements and issues.

Epigenetic Divergence during Early Stages of Speciation in an African Crater Lake Cichlid Fish

Epigenetic variation can alter transcription and promote phenotypic divergence between populations facing different environmental challenges. Here we assess the epigenetic basis of diversification during the early stages of speciation. We focus on the extent and functional relevance of DNA methylome divergence between two Astatotilapia calliptera ecomorphs in crater Lake Masoko, southern Tanzania. We report extensive genome-wide methylome divergence between populations linked to key biological processes, including transcriptional activity of ecologically-relevant genes. These include genes involved in steroid metabolism, haemoglobin composition and erythropoiesis, consistent with divergent habitat occupancy of the ecomorphs. Using a common garden experiment, we found that global methylation profiles are rapidly remodelled across generations, but ecomorph-specific differences can be inherited. Collectively, our study suggests an epigenetic contribution to early stages of vertebrate speciation.