The anatomy and histology of the reproductive tract of the male Babirusa (Babyrousa celebensis).

The anatomy and histology of the reproduction organs of the male Babirusa (Babyrousa celebensis) were studied in 21 specimens collected between birth and approximately 17 years of age. In adult animals the testes were located in a subanal position against the caudal surface of the thigh musculature. Average adult testis length was 68.9 ± 5.1 mm, width was 40.3 ± 5.7 mm, and depth was 47.9 ± 7.0 mm (N = 11). The average combined adult testicular weight was estimated to be 82.7 ± 23.2 g (N = 11). The testes of newborn Babyrousa had descended through the inguinal canal into the scrotum before birth. Adult seminiferous tubules had an average diameter of 199 ± 33.6 µm (N = 9) and were randomly distributed among a smaller volume of Leydig cells. Connective tissue was sparse. In one 13-month-old prepubertal animal the diameter of the seminiferous tubules was 85.3 ± 16.1 µm (N = 7). The spermatozoa was 42.2 ± 4.9 µm (N = 19) long and had a flat, paddle shaped head, 6.3 ± 0.6 µm (N = 50) long, 3.9 ± 0.5 µm (N = 47) wide, and a thickness of approximately 0.5 µm. An apical ridge along its front represented the acrosome. The two adult vesicular glands each had an irregular shape and were approximately 48.7 ± 7.4 mm long, 25.6 ± 4.3 mm wide, and 20.6 ± 8.7 mm deep (N = 6). The prostate, comprising a corpus and disseminate parts, lay ventral to the vesicular glands partly embedded in the dorsal wall of the urethra. The paired adult bulbourethral glands were approximately shaped like prolate (elongated) spheroids and had a length of 51.2 ± 14.2 mm, a width of 22.6 ± 4.5 mm, and a depth of 14.4 ± 4.5 mm (N = 7). The secretions from the bulbourethral glands drained into the urethral recess, which in adults measured approximately 10 to 14 mm in length and was located caudodorsal to a narrowing of the pelvic urethra. The penis was 330 ± 16 mm long and 8.2 ± 0.6 mm in diameter, and rotated approximately two and a half turns counterclockwise along its longitudinal axis toward its free end. The small prepucial diverticulum situated dorsocranial to the penis tip in adult and prepubertal Babyrousa, in adults measured 22.0 ± 1 mm in length and 17.5 ± 2.6 mm (N = 3) in width.

Vertebral column, rib and sternal muscles of Sulawesi Babirusa (Babyrousa celebensis).

The muscular anatomy of the vertebrae, ribs and sternebrae of the Sulawesi Babirusa (Babyrousa celebensis) is described. There are many similarities to the anatomy of the domestic pig (Sus scrofa). However, unlike other pigs, the M. spinalis et semispinalis cervicis et thoracis has an origin from the twelfth thoracic mamillary process. Similarly, the Babyrousa does not have the lumbar part of the M. obliquus internus abdominis which is found in other pigs. The M. sacrocaudalis dorsalis medialis of the Babyrousa is not fused to the Mm. multifidi, and the origin of the M. obliquus externus abdominis in the Babyrousa does not include rib 4 or the fascia thoracolumbalis. In the Babyrousa, the M. longissimus atlantis is clearly separated from the M. longissimus capitis, whereas in Sus the two are fused and have a more caudal origin (up to the second thoracic vertebra). The M. longissimus cervicis of the Babyrousa has a less extensive origin and insertion than is found in the domestic pig which may be related to differences between each species in its ability to dig with its nose.

Cranial muscles of the Sulawesi Babirusa (Babyrousa celebensis).

The detailed muscular anatomy of the head of the Sulawesi Babirusa (Babyrousa celebensis) is described for the first time. The results show that the muscular anatomy of the Babyrousa is very similar to the pig genus Sus, despite long geological separation from it. Some differences were noted: the M. parietoauricularis was more clearly separated into two parts in the Babirusa than in the domestic pig; the rostral fibres of the M. levator anguli oculi reached the infraorbital sinus in the Babirusa but only as far as the medial corner of the eye in the domestic pig; the M. palatinus of the Babirusa is paired and did not reach the Os palatinum, unlike its description in the domestic pig and the Platysma pars zygomatica originates from the fascia of the neck in the Babirusa, whereas that of the domestic pig originates largely or entirely from the scapula.