Crocodilian Phallic Malformations and Anomalies
Phallic malformations directly affect crocodilian copulatory function and thus could influence reproductive success in individual animals. This case series characterizes malformations observed and the implied reproductive consequences. A range of phallic malformations observed in saltwater crocodile (Crocodylus porosus), Nile crocodile (Crocodylus niloticus), broad-snouted caiman (Caiman latirostris), and Cuban crocodile (Crocodylus rhombifer) were assessed during veterinary examinations or postmortem studies; the observations were characterized into the following categories: amputation, phallic glans malformations, sulcus spermaticus obstruction, and prolapse. Through detailed descriptions of these anomalies, potential reproductive health effects based on current knowledge across crocodilian species is discussed. When considering captive management of breeding stock, it is vital to examine individual effectiveness at achieving proper intromission and insemination. Therefore, full reproductive examination in males should be part of routine examination to best care for individuals with such anomalies.Abstract
Morphological variance between juvenile male phallic glans of the American alligator (Alligator mississippiensis, left) and the Nile crocodile (Crocodylus niloticus, right) following artificial inflation of the corpus spongiosum (technique per Moore et al. [2021]) during necropsy. (A) Lateral view; (B) distal view. G = glans ridge; GT = glans tip.
Broad-snouted caiman (Caiman latirostris) phallic glans malformations. (A) Normal glans morphology-ventral view. (B) Bisected and deflected glans tip (see arrows pointing to distal tips). (C, D) Bisected glans ridge ventral and lateral view, respectively. G = glans ridge; GT = glans tip; SS = sulcus spermaticus. Scale bar = 1 cm.
Malformation of a juvenile Nile crocodile (Crocodilus niloticus) phallic glans. (A) Normal glans morphology, lateral view. (B, C) Bifurcated abnormal glans, dorsal and oblique views, respectively (see asterisks). (D) Histological section through bifurcation (solid black arrow) showing corpus spongiosum division. (E) Computer generated, three-dimensional reconstruction of the malformed glans seen in (B) and (C) with transparent epithelium showing subjacent structures. G = glans; GT = glans tip; CF = corpus fibrosum (pink); CS = corpus spongiosum (green); SS = sulcus spermaticus (purple).
Cuban crocodile (Crocodylus rhombifer) phallic malformations. (A) Normal sulcus spermaticus. (B) Eroded sulcus spermaticus. (C) Normal glans, lateral view. (D) Malformed (arrow) and necrotic glans. (E) Normal glans, distal aspect. (F) Malformed (arrow) glans, distal aspect. G = glans; GT = glans tip; SS = sulcus spermaticus.
Serial MRIs of malformed broad-snouted caiman (Caiman latirostris) phallic glans from Figure 2D. (A–C) Proximal to distal axial sections. CF = corpus fibrosum; CS = corpus spongiosum; GT = glans tip; SS = sulcus spermaticus.
Adult male phallic glans amputation examples. (A, B) Saltwater crocodile (Crocodylus porosus). (C, D) Broad-snouted caiman (Caiman latirostris). (E) Cuban crocodile (Crocodylus rhombifer). Cr = crura; SS = sulcus spermaticus.
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