@article {57395,
	title = {Growling from the gut: co-option of the gastric mill for acoustic communication in ghost crabs},
	year = {2019},
	abstract = {<p>Animal acoustic communication systems can be built upon co-opted structures that become specialized for sound production or morphological novelties. The ghost crab, Ocypode quadrata, evolved a novel stridulation apparatus on the claws that is used during agonistic interactions, but they also produce a rasping sound without their claw apparatus. We investigated the nature of these sounds and show that O. quadrata adopted a unique and redundant mode of sound production by co-opting the gastric mill (grinding teeth of the foregut). Acoustic characteristics of the sound are consistent with stridulation and are produced by both male and female crabs during aggressive interactions. Laser Doppler vibrometry localized the source of maximum vibration to the gastric region and fluoroscopy showed movement of the gastric mill that coincided with stridulation. The lateral teeth of the gastric mill possess a series of comb-like structures that rub against the median tooth to produce stridulation with dominant frequencies below 2 kHz. This previously undescribed gastric stridulation can be modulated and provide a means of assessment during aggressive interactions, similar to the use of the claw stridulation apparatus. This functional redundancy of stridulation in crabs offers unique insights into the mechanisms of evolution of acoustic communication systems.</p>
},
	keywords = {animal behaviour, bioacoustics, Crustacea, functional morphology, Ocypode},
	doi = {10.1098/rspb.2019.1161},
	url = {https://royalsocietypublishing.org/doi/10.1098/rspb.2019.1161https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2019.1161},
	author = {Taylor, Jennifer R. A. and deVries, Maya S. and Elias, Damian O.}
}
@article {57364,
	title = {Sound production mechanism in the Brazilian spiny lobsters (Family Palinuridae)},
	journal = {Zoomorphology},
	year = {2019},
	month = {Apr-08-2021},
	abstract = {<p>Strident lobsters of the Palinuridae family emit sounds in the presence of predators that can be used in the acoustic monitoring of such species. This study aims to identify sound emission and describe the structures of sound mechanism in red (Panulirus meripurpuratus) and green (Panulirus laevicauda) Brazilian spiny lobsters. The lobsters were collected in the environment, and recordings were performed in laboratory tanks with submerged hydrophones. The animals were stimulated to emit sound by the presence of an artificial octopus in the tank. The sounds emitted by the lobsters were analyzed by means of the waveform, and the structures involved (plectrum and file) were observed using scanning electron microscopy (SEM). Both species emitted a rasp sound composed of several pulses, with a rate varying from 125 to 265 pulses per second. The SEM showed that the file is similar between the species and it is covered by microscopic plates (shingles) measuring between 12.6 and 12.9 \&mu;m of medial\&ndash;lateral width and 6.2 \&mu;m and 7.1 \&mu;m of anteroposterior length. This analysis also revealed for the first time the presence of pores (\&lt;\&thinsp;1 \&mu;m in diameter) with vestiges of cuticular setae in-between the shingles, which could be involved in the mechanosensory control of sound production in lobsters. The results of this study corroborate the morphological pattern of sound emission structure described for other lobsters of the genus Panulirus.</p>
},
	keywords = {bioacoustics, Panulirus, Rasp, stridulation},
	issn = {0720-213X},
	doi = {10.1007/s00435-019-00461-5},
	url = {http://link.springer.com/10.1007/s00435-019-00461-5},
	author = {Hamilton, Santiago and Silva, Jos{\'e} Filipe and Pereira-Neves, Antonio and Travassos, Paulo and Peixoto, Silvio}
}
