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Within-species morphological variation is often observed across spatial and climatic gradients. Understanding this variation is important to conservation planning, as specialised adaptations may influence a population’s persistence following translocation. However, knowing whether local adaptations are prevalent within a species can be challenging when the species has undergone range contractions. Here, we used museum specimens to study size and shape variation of the greater stick-nest rat (Leporillus conditor). We aimed to determine whether intraspecific size and shape variation previously existed within the species across its historical range, and inform on possible implications for translocations of the remaining extant population. We found significantly larger skull size in the Franklin Islands and arid populations, possibly indicating a historically continuous population experiencing similar selection pressures such as high predation pressure, competition with other large arid zone rodents or climatic extremes. Conversely, skull shape variation within the species adheres to an allometric trajectory, indicating no specific local adaptations of skull shape. This absence of local skull shape adaptation suggests that the Franklin Islands population is likely suitable for mainland translocations. However, further research into the historical phylogeography of the species is recommended to identify whether large size resulted from shared ancestry or convergent evolution.

Conservation genomics research often relies on accurate sex information to make inferences about species demography, dispersal, and population structure. However, field determined sex data are not always available and can be subject to human error, while laboratory sex assignment methods such as PCR assays can often be costly and challenging for non-model species. Conservation genomics programs increasingly use reduced-representation genome sequencing to assess neutral and functional genetic diversity, population structure, gene flow and pedigrees in threatened species. Here we demonstrate that sex can be determined from reduced-representation sequencing data produced by the increasingly popular Diversity Arrays Technology sequencing workflow (DArT-seq) using a program originally designed for application to shotgun data. This program—sexassign—compares the “dosage” of sequencing reads mapping to autosomes versus the X chromosome. In the present study, sexassign was used to identify the sex of 60 field-collected Greater Stick-Nest Rat (Leporillus conditor) samples, despite the absence of an annotated reference genome for the species. This “read-dosage” approach is not only more accurate and affordable than traditional sex assignment methods, but can be applied to any diploid organism with a heterogametic sex determination system—including non-model and understudied species of conservation importance—by using FASTQs generated by DArT.

Allen’s rule is an ecogeographical pattern whereby the size of appendages of animals increases relative to body size in warmer climates in order to facilitate heat exchange and thermoregulation. Allen’s rule predicts that one consequence of a warming climate would be an increase in the relative size of appendages, and evidence from other bird species suggests that this might be occurring. Using measurements from museum specimens, we determined whether spatio-temporal variation in bills and legs of Australian Pachycephalidae species exhibits within-species trends consistent with Allen’s rule and increases in temperature attributable to climatic warming. We conducted regression model analyses relating appendage size to spatio-temporal variables, while controlling for body size. The relative bill size in four of the eight species was negatively associated with latitude. Tarsus length showed no significant trends consistent with Allen’s rule. No significant increases in appendage size were found over time. Although bill size in some species was positively correlated with warmer temperatures, the evidence was not substantial enough to suggest a morphological response to climatic warming. This study suggests that climate change is not currently driving adaptive change towards larger appendages in these species. We suggest that other adaptive mechanisms might be taking place.

Conservation genomics research often relies on accurate sex information to make inferences about species demography, dispersal, and population structure. However, field determined sex data are not always available and can be subject to human error, while laboratory sex determination is costly and often challenging for non-model species. Conservation genomics programs increasingly use reduced-representation genome sequencing to assess neutral and functional genetic diversity, population structure, gene flow and pedigrees in threatened species. Here we demonstrate that sex can be determined from reduced-representation sequencing data produced by the increasingly popular Diversity Arrays Technology sequencing workflow (DArT-seq) using a program originally designed for application to shotgun data. This program – sexassign – compares the “dosage” of sequencing reads mapping to autosomes versus the X chromosome. In the present study, sexassign accurately determined the sex of 60 field-collected Greater Stick-Nest Rat (Leporillus conditor) samples, despite the absence of an annotated reference genome for the species. This “read-dosage” approach is not only more accurate and affordable than traditional sex determination methods, but can be applied to any diploid organism with a heterogametic sex determination system – including non-model and understudied species of conservation importance – by using FASTQs generated by DArT.