Guido Fritsch

Ultrasonography of the Urogenital Tract in Elephants (Loxodonta africana and Elephas maximus): An Important Tool for Assessing Male Reproductive Function

The success rate of captive elephant breeding programs worldwide is poor. Along with undiagnosed reproductive disorders in females and fatal diseases such as the newly discovered herpesvirus infection, male infertility now is considered a major contributing factor in the failure to maintain self-sustaining captive populations. To address questions related to male reproductive dysfunction, approximately 309 ultrasonographic assessments combined with semen collection were performed in captive (n = 10) and wild (n = 4) African (Loxodonta africana) and captive (n = 61) Asian (Elephas maximus) elephants. Bulls ranged from 4 to 50 years of age and were examined at 9 institutions in North America, 13 in Europe, 2 in Africa, and 7 in Asia. About half of the reproductive assessments were performed in protected contact situations with elephants handled in a restraint device, and half involved assessments of trained Asian bulls managed in free contact. Four wild African and two Asian elephant bulls were evaluated after receiving general anesthesia. Transrectal ultrasound was used to characterize the morphology and functionality of the entire urogenital tract, including the testes and accessory sex organs. Bulls were categorized on the basis of breeding status (breeders vs. non-breeders) and social history (i.e., type of interaction with conspecifics and keepers). Most of the bulls were non-breeders (designated Types I–V). Type I (n = 3 African, 6 Asian) and Type V (n = 1 Asian) were immature and castrate, respectively. On the basis of keeper evaluations, Type II bulls (n = 2, 4) were subordinate to older cows and keepers, whereas Type III bulls (n = 4, 28) were dominated by other bulls. Type IV (n = 1, 8) were older bulls of unknown history that exhibited numerous testicular pathologies resulting in poor semen quality. Non-breeding bulls included those that were exposed to females, but failed to breed, as well as those that had no opportunities to breed. Type VI individuals (n = 4, 14) were proven breeders. The percentage of observable reproductive tract pathology in adult males was remarkably low (14%), even in older bulls. However, apparent infertility of non-organic cause (i.e., not due to specific anatomical abnormalities) in these otherwise healthy bulls was high (32%). Semen quality varied markedly in ejaculates collected from the same bull, as well as from different bulls. In conclusion, although many of these bulls could serve as semen donors for natural mating or artificial insemination, the inconsistent production of good-quality ejaculates raises questions as to the reliability of these individuals to participate in breeding programs. The apparent inhibitory effect of suppressive social interactions on reproductive potential also needs to be investigated. Ultrasound examinations combined with semen collection should be conducted periodically to estimate the reproductive value of each bull and determine whether altered management strategies are needed to enhance captive breeding. Zoo Biol 19:333–345, 2000.

Ultrasonography of the estrous cycle in female African elephants (Loxodonta africana)

The endocrinology of the elephant estrous cycle has been well characterized, but little emphasis has been placed on evaluating corresponding changes in the reproductive tract. Ultrasound was used to document changes in reproductive tract morphology throughout the estrous cycle in four cycling female African elephants. During a 7-month period, frequent ultrasound examinations (n = 190) during the luteal and non-luteal phase were compared with serum progesterone and luteinizing hormone (LH) concentrations during a 7-month period. Ultrasonographic images documented vaginal and cervical edema and changes in mucus consistency during the non-luteal phase. The cross-sectional diameter of the endometrium showed a dramatic increase during the non-luteal phase and followed cyclic changes. A different pattern of follicular development on the ovary was associated with the two LH surges. Follicle growth associated with the first, anovulatory LH surge was characterized by the formation of multiple small follicles, in contrast to the maturation of a single large follicle at the second, ovulatory LH (ovLH) surge. Ovulation and the subsequent formation of a corpus luteum (CL) were observed only after the ovLH surge. Ultrasound data in combination with endocrine assessments suggest that the African elephant is non-ovulatory, although multiple non-ovulatory luteal structures developed during the late nonluteal phase of each cycle. Both ovulatory CL and non-ovulatory luteal structures were present only through one cycle and regressed at the end of the luteal phase in conjunction with the drop in serum progesterone. We conclude that

Ontogenetic scaling of foot musculoskeletal anatomy in elephants

This study quantifies the shape change in elephant manus and pes anatomy with increasing body mass, using computed tomographic scanning. Most manus and pes bones, and manus tendons, maintain their shape, or become more gracile, through ontogeny. Contrary to this, tendons of the pes become significantly more robust, suggesting functional adaptation to increasingly high loads. Ankle tendon cross-sectional area (CSA) scales the highest in the long digital extensor, proportional to body mass1.08±0.21, significantly greater than the highest-scaling wrist tendon (extensor carpi ulnaris, body mass0.69±0.09). These patterns of shape change relate to the marked anatomical differences between the pillar-like manus and tripod-like pes, consistent with differences in fore- and hindlimb locomotor function. The cartilaginous predigits (prepollux and prehallux) of the manus and pes also become relatively more robust through ontogeny, and their pattern of shape change does not resemble that seen in any of the 10 metacarpals and metatarsals. Their CSAs scale above isometry proportional to body mass0.73±0.09 and body mass0.82±0.07 respectively. We infer a supportive function for these structures, preventing collapse of the foot pad during locomotion.

Mobile larynx in Mongolian gazelle: Retraction of the larynx during rutting barks in male Mongolian gazelle (Procapra gutturosa Pallas, 1777).

This study provides the first evidence of pronounced temporary laryngeal descent in a bovid species. An elaborate acoustic display is prominent in male courtship behavior of polygynous Mongolian gazelle. During rut, rounding up of females is accompanied by continuous head‐up barking by dominant males. Throughout the rut their evolutionarily enlarged larynx descends to a low mid‐neck resting position. In the course of each bark the larynx is additionally retracted toward the sternum by 30% of the resting vocal tract length. A geometric model of active larynx movements was constructed by combining results of video documentation, dissection, skeletonization, and behavioral observation. The considerable distance between resting position and maximal laryngeal descent suggests a backward tilting of the hyoid apparatus and an extension of the thyrohyoid connection during the retraction phase. Return to the resting position is effected by strap muscles and by the elastic recoil of the pharynx and the thyrohyoid connection. An intrapharyngeal inflation of the peculiar palatinal pharyngeal pouch of adult males is inferred from a short‐time expansion of the ventral neck region rostral to the laryngeal prominence. The neck of adult dominant males is accentuated by long gray guard hairs during the rut. The passive swinging of the heavy larynx of adult males during locomotion gives the impression of a handicap imposed on rutting males. Apparently, this disadvantage becomes outweighed by the profits for reproductive success. J. Morphol., 2008.

The Anatomical Foundation for Multidisciplinary Studies of Animal Limb Function: Examples from Dinosaur and Elephant Limb Imaging Studies

What makes so many animals, living and extinct, so popular and distinct is anatomy; it is what leaps out at a viewer first whether they observe a museum’s mounted Tyrannosaurus skeleton or an elephant placidly browsing on the savannah. Anatomy alone can make an animal fascinating — so many animals are so physically unlike human observers, yet what do these anatomical differences mean for the lives of animals?

Evidence of Spondyloarthropathy in the Spine of a Phytosaur (Reptilia: Archosauriformes) from the Late Triassic of Halberstadt, Germany

Pathologies in the skeleton of phytosaurs, extinct archosauriform reptiles restricted to the Late Triassic, have only been rarely described. The only known postcranial pathologies of a phytosaur are two pairs of fused vertebrae of “Angistorhinopsis ruetimeyeri” from Halberstadt, Germany, as initially described by the paleontologist Friedrich von Huene. These pathologic vertebrae are redescribed in more detail in this study in the light of modern paleopathologic methods. Four different pathologic observations can be made in the vertebral column of this individual: 1) fusion of two thoracic vertebral bodies by new bone formation within the synovial membrane and articular capsule of the intervertebral joint; 2) fusion and conspicuous antero-posterior shortening of last presacral and first sacral vertebral bodies; 3) destruction and erosion of the anterior articular surface of the last presacral vertebra; and 4) a smooth depression on the ventral surface of the fused last presacral and first sacral vertebral bodies. Observations 1–3 can most plausibly and parsimoniously be attributed to one disease: spondyloarthropathy, an aseptic inflammatory process in which affected vertebrae show typical types of reactive new bone formation and erosion of subchondral bone. The kind of vertebral shortening present in the fused lumbosacral vertebrae suggests that the phytosaur acquired this disease in its early life. Observation 4, the smooth ventral depression in the fused lumbosacral vertebrae, is most probably not connected to the spondyloarthropathy, and can be regarded as a separate abnormality. It remains of uncertain origin, but may be the result of pressure, perhaps caused by a benign mass such as an aneurysm or cyst of unknown type. Reports of spondyloarthropathy in Paleozoic and Mesozoic reptiles are still exceptional, and our report of spondyloarthropathy in fossil material from Halberstadt is the first unequivocal occurrence of this disease in a Triassic tetrapod and in a phytosaur.

The postnatal ontogeny of the sexually dimorphic vocal apparatus in goitred gazelles (Gazella subgutturosa)

This study quantitatively documents the progressive development of sexual dimorphism of the vocal organs along the ontogeny of the goitred gazelle (Gazella subgutturosa). The major, male‐specific secondary sexual features, of vocal anatomy in goitred gazelle are an enlarged larynx and a marked laryngeal descent. These features appear to have evolved by sexual selection and may serve as a model for similar events in male humans. Sexual dimorphism of larynx size and larynx position in adult goitred gazelles is more pronounced than in humans, whereas the vocal anatomy of neonate goitred gazelles does not differ between sexes. This study examines the vocal anatomy of 19 (11 male, 8 female) goitred gazelle specimens across three age‐classes, that is, neonates, subadults and mature adults. The postnatal ontogenetic development of the vocal organs up to their respective end states takes considerably longer in males than in females. Both sexes share the same features of vocal morphology but differences emerge in the course of ontogeny, ultimately resulting in the pronounced sexual dimorphism of the vocal apparatus in adults. The main differences comprise larynx size, vocal fold length, vocal tract length, and mobility of the larynx. The resilience of the thyrohyoid ligament and the pharynx, including the soft palate, and the length changes during contraction and relaxation of the extrinsic laryngeal muscles play a decisive role in the mobility of the larynx in both sexes but to substantially different degrees in adult females and males. Goitred gazelles are born with an undescended larynx and, therefore, larynx descent has to develop in the course of ontogeny. This might result from a trade‐off between natural selection and sexual selection requiring a temporal separation of different laryngeal functions at birth and shortly after from those later in life. J. Morphol. 277:826–844, 2016.

Head Anatomy of Male and Female Mongolian Gazelle — A Striking Example of Sexual Dimorphism

The first scientific description of the Mongolian gazelle by Pallas (1777) already depicted a sexual dimorphism of the larynx and the thyrohyoid connection (Fig 1.1). Open image in new window

Vocal development during postnatal growth and ear morphology in a shrew that generates seismic vibrations, Diplomesodon pulchellum

The ability of adult and subadult piebald shrews (Diplomesodon pulchellum) to produce 160Hz seismic waves is potentially reflected in their vocal ontogeny and ear morphology. In this study, the ontogeny of call variables and body traits was examined in 11 litters of piebald shrews, in two-day intervals from birth to 22 days (subadult), and ear structure was investigated in two specimens using micro-computed tomography (micro-CT). Across ages, the call fundamental frequency (f0) was stable in squeaks and clicks and increased steadily in screeches, representing an unusual, non-descending ontogenetic pathway of f0. The rate of the deep sinusoidal modulation (pulse rate) of screeches increased from 75Hz at 3-4 days to 138Hz at 21-22 days, probably relating to ontogenetic changes in contraction rates of the same muscles which are responsible for generating seismic vibrations. The ear reconstructions revealed that the morphologies of the middle and inner ears of the piebald shrew are very similar to those of the common shrew (Sorex araneus) and the lesser white-toothed shrew (Crocidura suaveolens), which are not known to produce seismic signals. These results suggest that piebald shrews use a mechanism other than hearing for perceiving seismic vibrations.

Potential Sources of High Frequency and Biphonic Vocalization in the Dhole (Cuon alpinus)

Biphonation, i.e. two independent fundamental frequencies in a call spectrum, is a prominent feature of vocal activity in dog-like canids. Dog-like canids can produce a low (f0) and a high (g0) fundamental frequency simultaneously. In contrast, fox-like canids are only capable of producing the low fundamental frequency (f0). Using a comparative anatomical approach for revealing macroscopic structures potentially responsible for canid biphonation, we investigated the vocal anatomy for 4 (1 male, 3 female) captive dholes (Cuon alpinus) and for 2 (1 male, 1 female) wild red fox (Vulpes vulpes). In addition, we analyzed the acoustic structure of vocalizations in the same dholes that served postmortem as specimens for the anatomical investigation. All study dholes produced both high-frequency and biphonic calls. The anatomical reconstructions revealed that the vocal morphologies of the dhole are very similar to those of the red fox. These results suggest that the high-frequency and biphonic calls in dog-like canids can be produced without specific anatomical adaptations of the sound-producing structures. We discuss possible production modes for the high-frequency and biphonic calls involving laryngeal and nasal structures.