The tongue morphology and lingual gland histochemistry of Ligurian Sea odontocetes

Abstract

The morphology and histomorphology of the tongue and the histochemistry of the lingual glands of eight specimens from four species of Ligurian Sea odontocetes (Stenella coeruleoalba, Tursiops truncatus, Grampus griseus, and Ziphius cavirostris) were studied. The shape of tongues and the appearance of their dorsal surfaces differed between species. The lingual glands differed in size, distribution, and histochemistry by species. In S. coeruleoalba and G. griseus, a strong alcianophilic mucous material was detected in the lingual glands, while neutral and acidic mucous substances were observed in the most proximal secretory acini. In G. griseus, small simple alveolar apocrine glands were also found, and the duct of the serous lingual glands in Z. cavirostris is of apocrine type. Numerous mechanoreceptors were observed. Only the tongue of the young specimens showed marginal papillae: their histomorphological composition is consistent with the hypothesis that they create a tight seal between the tongue and the roof of the cavity in order to create suction. This comparative study suggests that differences in tongue morphology and in the morphology and histochemistry of lingual glands might be related to feeding habits.

Tongue and Hyoid Musculature and Functional Morphology of a Neonate Gray Whale (Cetacea, Mysticeti, Eschrichtius robustus)

“…). We hypothesize that the marginal lingual papillae is an adaptation for latching on to the mother's nipple during suckling and the same could be true for the cleft tongue In many mammals (Yamasaki et al, ; Yamasaki and Takahashi, ; Evans, ; Schneider et al, ; Ateş et al, ), including whales (Kastelein and Dubbeldam, ; Shindo et al, ; Ferrando et al, ), the marginal lingual papillae are well developed in juveniles and become reduced or disappear after weaning. The marginal papillae in our specimen are well developed near the apex of the tongue (Fig.…”

Characterizing the suckling behavior by video and 3D-accelerometry in humpback whale calves on a breeding ground

“…The lateral aspect of the calf’s rostral tongue is comprised of elongated marginal papillae that may serve to grasp the nipple. This latching-on-nipple function has been proposed for newborn tongues in other whale species ( Kastelein & Dubbeldam, 1990 ; Shindo et al, 2008 ; Ferrando et al, 2010 ; Kienle et al, 2015 ). These marginal papillae may also ‘zipper’ together to form a tube for channeling milk into the mouth, compensating for the calf’s lack of lips and cheeks to seal and contain the nipple and the extruded milk.…”

Macro and microanatomy of some organs of a juvenile male Ganges River dolphin (Platanista gangetica spp. gangetica)

“…Furthermore, the shape of the tongue of Ganges River dolphin was smaller and oval. In contrast, other odontocete species show different shapes, such as long and narrow tongue in the Striped dolphin (Stenella coeruleoalba) and oval in Risso's dolphin ( Grampus griseus ; Ferrando et al, 2010). This smaller tongue with elongated beaks in Ganges River dolphin is suitable for raptorial prehension, whereas a narrow and long tongue with a blunt rostrum in other species is better for suction feeding (Ferrando et al, 2010).…”

“…In contrast, other odontocete species show different shapes, such as long and narrow tongue in the Striped dolphin (Stenella coeruleoalba) and oval in Risso's dolphin ( Grampus griseus ; Ferrando et al, 2010). This smaller tongue with elongated beaks in Ganges River dolphin is suitable for raptorial prehension, whereas a narrow and long tongue with a blunt rostrum in other species is better for suction feeding (Ferrando et al, 2010). Furthermore, Considering the male genital system, the Clymene dolphin shows a unique retractor penis muscle (Spinelli et al, 2021), whereas the Ganges River dolphin shows a pair of retractor penis muscles.…”