16The observation of severe pelvic malformations in Eurasian lynx (Lynx lynx) from a 17 population reintroduced to Switzerland raised the question as to whether inbreeding may 18 contribute to the development of congenital pelvic malformations. We aimed at providing 19 baseline data on the pelvic morphology of Eurasian lynx from the reintroduced populations in 20 Switzerland, at assessing potential differences in pelvic conformation between the two main 21 Swiss populations, among age classes and between sexes, and at detecting pelvic anomalies. 22 We performed measurements of 10 pelvic parameters on the radiographs of 57 lynx of both 23 sexes and different ages taken from 1997-2015. We calculated two ratios (vertical 24 diameter/acetabula; sagittal diameter/transversal diameter) and two areas (pelvic outlet and 25 inlet) to describe the shape of the pelvis. Our results showed that the Eurasian lynx is a 26 mesatipelvic species, with a pelvis length corresponding to approximatively 20% of the body 27 length. We found no statistically significant differences between the two examined 28 populations but observed growth-related pelvis size differences among age groups. Sexual 29 dimorphism was obvious in the adult age group only: two parameters reflecting pelvic width 30 were larger in females, likely to meet the physiological requirements of parturition. By 31 contrast, pelvis length, conjugata vera, diagonal conjugata, vertical diameter and sagittal 32 diameter were larger in males, in agreement with their larger body size. Accordingly, the ratio 33 between the sagittal and transversal diameters was significantly larger in males, i.e. adult 34 males have a different pelvic shape than adult females. Furthermore, pelvimetry highlighted 35 one adult individual with values outside the calculated reference range, suggesting a possible 36 congenital or developmental pathological morphology of the internal pelvis. Our work 37 generated baseline data of the pelvic morphology including growth and sexual dimorphism of 38 the Eurasian lynx. These data could also be useful for estimating age and sex in skeletal 39 remains. 42 end of the 19th century. Following habitat improvementy and prey recovery, lynx 43 reintroductions took place in the 1970s, with lynx imported from the Capathian Mountains in 44 Slovakia. In Switzerland, two small distinct lynx populations resulted from these releases: one 45 in the Swiss Alps extending slightly into France and Italy, and another one in the Jura 46 Mountains at the border with France, both estimated at approximatively 100-150 independent 47 lynx, with a total of approximately 130-140 lynx in the Swiss territory (1). However, these 48 populations are now characterized by a low genetic variability and a high inbreeding 49 coefficient (2). 50 A lynx health monitoring program has been conducted at the Centre for Fish and 51 Wildlife Health (FIWI) in Switzerland for several decades, including necropsies of carcasses, 52 clinical examinations of live lynx and systematic sampling. From 200...

The observation of pelvic anomalies in two Eurasian lynx (subspecies Lynx lynx carpathicus) from a population reintroduced to Switzerland raised the question of the frequency of such anomalies, but no anatomical reference values were available for comparison. This study aimed at providing baseline data on the pelvic morphology of Carpathian lynx from Switzerland, and at detecting potential pelvic anomalies. Measurements of 10 pelvic parameters were performed on the radiographs of 56 lynx taken from 1997–2015. Two ratios (vertical diameter/acetabula; sagittal diameter/transversal diameter) and two areas (pelvic outlet and inlet) were calculated to describe pelvic shape. The results showed that the Eurasian lynx has a mesatipellic pelvis, with a pelvic length corresponding to approximatively 20% of the body length. We found growth-related pelvis size differences among age classes and evidence of sexual dimorphism in adults: two parameters reflecting pelvic width were larger in females, likely to meet the physiological requirements of parturition. By contrast, pelvis length, conjugata vera, diagonal conjugata, sagittal diameter, and tendentially also vertical diameter, were larger in males, in agreement with their larger body size. Outliers were found in five individuals but apparently without clinical significance. Extreme values were likely due to inter-individual differences and the limited sample size rather than to possible congenital or developmental pathological morphology of the pelvic cavity. We present baseline data of the pelvic morphology, including growth and sexual dimorphism, which may be useful for health monitoring and for determination of age and sex in skeletal remains of Carpathian lynx.