Petrochirus

Stimpson, 1858

Species Guides

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Petrochirus is a of marine hermit crabs in the Diogenidae, comprising seven described . The genus was established by William Stimpson in 1858. Species in this genus exhibit in cheliped size, with males bearing larger claws than females. They inhabit subtropical to tropical marine coastal waters, typically at depths of 6–10 meters. The genus has a fossil record extending to the early Pleistocene in the Mediterranean region.

Petrochirus diogenes by (c) Eridan Xharahi, some rights reserved (CC BY). Used under a CC-BY license.Giant Hermit Crab (11670683275) by FWC Fish and Wildlife Research Institute. Used under a CC BY 2.0 license.Giant Hemit Crab (11354825876) by FWC Fish and Wildlife Research Institute. Used under a CC BY 2.0 license.

Pronunciation

How to pronounce Petrochirus: /pɛˈtroʊkɪrəs/

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Identification

Heterochely (right cheliped larger than left) present in both sexes; males have significantly larger chelipeds than females. Cephalothoracic shield width follows isometric growth. Shell use patterns show negative allometry—larger crabs occupy proportionally lighter shells relative to body weight.

Images

Habitat

Marine subtropical coastal waters, typically at depths of 6.0–10.0 m. Collected by commercial fishing with double-rig drag nets, indicating benthic .

Distribution

Western Atlantic: documented from Ubatuba region, São Paulo State, Brazil (23°20'-23°35'S, 44°50'-45°14'W) and Armação of Itapocoroy, Penha, Santa Catarina, southern Brazil. Fossil record: early Pleistocene of Podere dell'Infrascato, Volterra, Tuscany, central Italy (upper bathyal zone).

Seasonality

Ovigerous females occur January–April and September–December.

Life Cycle

Females smaller than 10.0 mm cephalothoracic shield length considered ; smallest ovigerous female recorded at 10.0 mm shield length. Mean cephalothoracic length in 30.61±12.52 mm.

Behavior

Feeding stimulated by chemical cues; exhibits chemotactic responses to food-related chemicals. Heterochely may be adaptive in agonistic interactions and precopulatory behavior.

Human Relevance

Subject of commercial fishing operations using double-rig nets in Brazil.

Sources and further reading