Morphology and histology of the larynx of the common toad Rhinella arenarum (Hensel, 1867) (Anura, Bufonidae)

Abstract

Hermida, G.N. and Farías, A. 2009. Morphology and histology of the larynx of the common toad Rhinella arenarum (Hensel, 1867) (Anura, Bufonidae). -Acta Zoologica (Stockholm) 90: 326-338The structure of the larynx of the toad Rhinella arenarum was exhaustively studied. The laryngeal skeleton consists of three bilaterally symmetrical cartilages: the cricoid and two arytenoids. Internally, each half-larynx has an anterior and a posterior chamber. The first chamber is delimited by the epithelium covering the arytenoid cartilage and the anterior membrane. The latter consists of fibro-elastic tissue and contains blood capillaries that, judging by their location and distribution, might serve to maintain vocal cord turgidity. At the level of the cricoid cartilage, two structures are reported here for the first time: the posterodorsal and the anteroventral processes. Both processes are associated with the insertion of the posterior membrane. A cartilaginous rod is located at the free margin of the posterior membrane. This rod appears to support the membrane when the air flows. The distal portion of the larynx communicates with the proximal region of the lung. The epithelium of the laryngeal mucosa contains ciliated cells, goblet cells, secretory cells with short microvilli and neuroendocrine cells immunopositive to PGP 9.5. The results obtained in this study provide new information about the internal organization of the larynx in anurans, which could serve as additional morphological characters for phylogenetic relationships.

Integrating morphology and physiology of the key endocrine organ during tadpole development: The interrenal gland

“…Since the opistonephric kidneys of young larvae are fragile and difficult to dissect, a few premetamorphic tadpoles were entirely sectioned in a sagittal plane. Sections were stained with Mallory's trichrome (AZAN; Kiernan, 1999) and modified with Masson's trichrome (MMT) for general cytology and histology (Hermida & Farías, 2009). We analyzed at least three individuals per Gosner stage.…”

Cranial muscles of the anuransleiopelma hochstetteriandascaphus trueiand the homologies of the mandibular adductors in lissamphibia and other gnathostomes

“…hochstetteri (Fig. 4A,C): the larynx is typical of the anuran pattern (Hermida and Farias, 2009) with a smaller dorsal chamber adjacent to the arytenoid cartilages, separated from the larger ventral chamber by the vocal chords. The laryngeal muscles comprise the dilator and constrictor: m. dilator laryngis originates from the postero-medial process of the branchial plate and inserts on the arytenoid cartilage rostrally.…”

Naturally occurring variability in larval period length is associated with intraspecific differences in late tadpoles of a South American true toad

“…To study the histo‐morphology of the kidney‐interrenal gland and the skin, kidneys and dissected tadpoles were embedded in paraplast (Leica Biosystems, St. Louis, MI, USA) and cross‐sectioned into 6‐μm‐thick slices. Sections of kidneys from early and late climax tadpoles were stained with Mallory's trichrome (AZAN; Kiernan, 1999) and modified Masson's trichrome (MMT) for general cytology and histology (Hermida & Farías, 2009). Sections of late climax tadpoles were stained with hematoxylin‐eosin (H‐E) or MMT for general histology of epidermis and dermal glands and with Alcian blue 8GX pH = 2.5 (Kiernan, 1999) plus hematoxylin (AB‐H) to evaluate gland secretions according to Regueira et al.…”