Feeding in Caecilians

O’Reilly, James C.

doi:10.1016/b978-012632590-4/50007-1

Cited by 33 publications

(67 citation statements)

References 65 publications

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“…Although this behaviour has been previously recorded for caecilians (Tanner 1971;Bemis et al 1983;O'Reilly 2000;Summers & Wake 2005), it has never been studied quantitatively and the functional significance has remained unclear (O'Reilly 2000). Long-axis body rotations are known from various groups of vertebrates, including reptiles (crocodiles) and fishes (eels), and are assumed to assist gape-limited predators that do not possess highly kinetic skulls in the reduction of large prey (Cott 1961;Helfman & Clark 1986).…”

Section: Discussionmentioning

confidence: 99%

“…Thus, our observations that caecilians frequently use long-axis body rotations when feeding, combined with the fact that these rotations impart significant torques on the head and jaws of the animal, may explain the origin of the unique jaw configuration in derived caecilians (Bemis et al 1983;Nussbaum 1983;O'Reilly 2000;Summers & Wake 2005), which allows them to generate large bite forces with their jaws closed (Summers & Wake 2005). While the reduction of oversized food items remains the most common explanation for long-axis body rotations during feeding, existing data on prey diameter and gape size (Delêtre & Measey 2004) suggest that caecilian prey are rarely oversized.…”

Section: G J Measey and A Herrel Spinning Caeciliansmentioning

confidence: 99%

“…Most caecilians appear to be generalist predators with the majority of prey items being earthworms and subterranean arthropods (Delêtre & Measey 2004;Gaborieau & Measey 2004;Kupfer et al 2005). Yet, observations of feeding behaviour in caecilians that could shed light on this apparent paradox are rare due to the subterranean existence of these animals (Tanner 1971;O'Reilly 2000;Summers & Wake 2005).…”

Section: Introductionmentioning

confidence: 99%

“…In association with their burrowing habit, most terrestrial species have sturdy, compact skulls, recessed mouths and reduced eyes sometimes covered by the bones of the skull roof. As the head-first burrowing lifestyle of caecilians puts severe constraints on maximal head diameter ( Wake 1993;O'Reilly 2000), the external jaw closer muscles, positioned at the side of the head, are strongly reduced in size in derived caecilians (Bemis et al 1983;Nussbaum 1983;O'Reilly 2000). However, the presence of a mobile quadrate (streptostyly) and a unique jaw-closing system involving the large and well-developed interhyoideus posterior muscle, positioned in line with the head (and thus not increasing the head diameter), suggests that these animals can generate considerable bite forces with the mouth closed (Summers & Wake 2005).…”

Section: Introductionmentioning

confidence: 99%

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Rotational feeding in caecilians: putting a spin on the evolution of cranial design

Measey

Herrel

2006

Biol. Lett.

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Caecilians are a poorly known group of amphibians with a highly derived skull and cranial musculature that has evolved in response to their specialized head-first burrowing lifestyle. They possess a unique jaw-closing system, which is shown to be capable of generating considerable bite forces for its head width (1.09±0.34 and 0.62±0.31 N for Schistometopum thomense and Boulengerula taitanus , respectively). However, comprehensive dietary studies indicate that there is no need for large bite forces, since most caecilians appear to be generalist predators of subterranean macrofauna. Here, we demonstrate, based on in vivo external and X-ray video recordings of animals feeding, that long-axis body rotations are used independent of prey size by these two species of caeciliid caecilians when feeding underground. Further, we show that individuals are capable of generating a substantial spinning force, which is greater than their bite force (1.35±0.26 and 1.02±0.18 N, respectively). These observations shed light on the functional and the evolutionary significance of several unique features of the cranial design in derived caecilians; spinning may allow the individuals to judge prey size and subsequently reduce oversized prey within gape limits.

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Section: Discussionmentioning

confidence: 99%

Section: G J Measey and A Herrel Spinning Caeciliansmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Rotational feeding in caecilians: putting a spin on the evolution of cranial design

Measey

Herrel

2006

Biol. Lett.

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“…In extant caecilians, the eyes are highly reduced and the skulls are well ossified to facilitate fossoriality (O'Reilly, 2000). Most of the extrinsic eye muscles have been either reduced in size or co-opted to function with a specialized sensory organ, the tentacle.…”

Section: Eye Retraction and Swallowing In Other Vertebratesmentioning

confidence: 99%

Contribution of eye retraction to swallowing performance in the northern leopard frog,Rana pipiens

Levine

Monroy

Brainerd

2004

Journal of Experimental Biology

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SUMMARY Most anurans retract and close their eyes repeatedly during swallowing. Eye retraction may aid swallowing by helping to push food back toward the esophagus, but this hypothesis has never been tested. We used behavioral observations, cineradiography, electromyography and nerve transection experiments to evaluate the contribution of eye retraction to swallowing in the northern leopard frog, Rana pipiens. Behavioral observations of frogs feeding on 1.5 cm long crickets reveal a high degree of variability in eye retraction and swallowing. Eye retraction can occur bilaterally or unilaterally, and both swallowing movements and eye retraction can occur separately as well as together. During swallowing, cineradiography shows that the eyes and associated musculature retract well into the oropharynx and appear to make contact with the prey item. This contact appears to help push the prey toward the esophagus, and it may also serve to anchor the prey for tongue-based transport. Electromyographic recordings confirm strong activity in the retractor bulbi muscles during eye retraction. After bilateral denervation of the retractor bulbi, frogs maintain the ability to swallow but show a 74% increase in the number of swallows required per cricket (from a mean of 2.3 swallows to a mean of 4.0 swallows per cricket). Our results indicate that, in Rana pipiens feeding on medium-sized crickets, eye retraction is an accessory swallowing mechanism that assists the primary tongue-based swallowing mechanism.

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Feeding Underground: Kinematics of Feeding in Caecilians

Herrel

Measey

2012

J. Exp. Zool.

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Caecilians are limbless amphibians that have evolved distinct cranial and postcranial specializations associated with a burrowing lifestyle. Observations on feeding behavior are rare and restricted to above-ground feeding in laboratory conditions. Here we report data on feeding in tunnels using both external video and X-ray recordings of caecilians feeding on invertebrate prey. Our data show feeding kinematics similar to those previously reported, including the pronounced neck bending observed during above-ground feeding. Our data illustrate, however, that caecilians may be much faster than previously suspected, with lunge speeds of up to 7 cm sec(-1). Although gape cycles are often slow (0.67 ± 0.29 sec), rapid jaw closure is observed during prey capture, with cycle times and jaw movement velocities similar to those observed in other terrestrial tetrapods. Finally, our data suggest that gape angles may be large (64.8 ± 18°) and that gape profiles are variable, often lacking distinct slow and fast opening and closing phases. These data illustrate the importance of recording naturalistic feeding behavior and shed light on how these animals are capable of capturing and processing prey in constrained underground environments. Additional data on species with divergent cranial morphologies would be needed to better understand the co-evolution between feeding, burrowing, and cranial design in caecilians.

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Feeding in Caecilians

Cited by 33 publications

References 65 publications

Rotational feeding in caecilians: putting a spin on the evolution of cranial design

Rotational feeding in caecilians: putting a spin on the evolution of cranial design

Contribution of eye retraction to swallowing performance in the northern leopard frog,Rana pipiens

Feeding Underground: Kinematics of Feeding in Caecilians

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