Biodiversity Data Journal :
Taxonomic paper
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The land crab Johngarthia planata (Stimpson, 1860) (Crustacea, Brachyura, Gecarcinidae) colonizes human-dominated ecosystems in the continental mainland coast of Mexico
Corresponding author:
Academic editor: Niamh Kilgallen
Received: 20 Jun 2014 | Accepted: 30 Jun 2014 | Published: 08 Jul 2014
© 2014 Robert Perger
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Perger R (2014) The land crab Johngarthia planata (Stimpson, 1860) (Crustacea, Brachyura, Gecarcinidae) colonizes human-dominated ecosystems in the continental mainland coast of Mexico. Biodiversity Data Journal 2: e1161. https://doi.org/10.3897/BDJ.2.e1161
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The land crab Johngarthia planata (Stimpson, 1860) has been reported from the Baja California Peninsula and several oceanic islands in the Eastern Pacific as well as inshore islands of the Mexican, Costa Rican and Colombian coast. However, the species has not been observed on the continental mainland, as it is likely that the high diversity of terrestrial predators/competitors make the establishment of mainland populations nearly impossible. In this contribution, several new records of this species that have been observed in urban areas along the continental Pacific coast of Mexico are reported. These records demonstrate that the presence of humans does not necessarily have a negative impact on land crab species. Indeed, the presence of humans may actually discourage the presence of native crab predators/competitors and hence increase the likelihood of a successful mainland settlement of land crab species that are otherwise island and peninsula restricted. The presence of J. planata is ecologically relevant for coastal forests because gecarcinid crabs significantly influence plant recruitment and J. planata is considerably larger than the mainland species Gecarcinus quadratus.
Brachyura, dispersal, distribution, East Pacific, Mexico, new record
Macroevolutionary transitions between marine and non-marine habitats are uncommon and rarely lead to long-term success in the invaded habitat (
However, while their larvae still develop in marine habitats, adults of the crab family Gecarcinidae have successfully conquered island habitats, where they play an important ecological role (
Nevertheless, despite their success on islands and possible dispersal in their larval stage via sea currents, most species of the Gecarcinus-group are absent from continental mainland habitats (
Johngarthia planata (Stimpson, 1860) appears to be a textbook example for the group's failure to establish itself on the continental mainland despite the advantages of ecological flexibility and favorable larval dispersion patterns (reviewed by
In this study I report the first continental mainland records for J. planata and discuss the possibility that human presence might actually facilitate the mainland settlement of such a species.
The present study encompasses the Pacific coast from Mexico to Colombia. Following
The following abbreviations are used in the text: LACM – Natural History Museum of Los Angeles County, Los Angeles, California; MNHN – Muséum National d’Histoire Naturelle, Paris, France; MZ-UCR – Museo de Zoología, Universidad de Costa Rica, San José, Costa Rica; USNM – National Museum of Natural History, Smithsonian Institution, Washington, D.C.
The Internet search revealed photographs of 12 individuals from Mexico (mainland) and three individuals from Panama (Iguana Island) (Table
Island and mainland records for Johngarthia planata obtained from the literature (L) and photographs (P); new records highlighted by (*).
Location |
Source |
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Colombia |
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Gorgona Island |
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Costa Rica |
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Colorada Island |
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Caño Island |
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Nairita Island |
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Panama |
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Iguana Island* |
María Elena Valencia 2006; Julio Larish 2013 (P) |
Mexico, islands |
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Clipperton Island |
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Pájaros Island, Michoacán |
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Isabela Island, Nayarit |
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Maria Cleofa Island, Nayarit |
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Pájaros Island, Sinaloa |
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San Pedro Nolasco Island, Gulf of California |
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Socorro Island |
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San Benedicto Island |
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Clarion Island |
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Bacochibampo Bay, Sonora (small reef) |
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Mexico, Baja California Peninsula |
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Cabo San Lucas |
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Mexico, mainland |
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Mazatlán, Sinaloa* |
Lisa Brettschneider 2008 (P) |
Sayulita, Nayarit* |
Lisa Johnston 2005; Tania Beagley-Brown 2007; Daniel Brewer 2010; Madeline Milne 2013 (P) |
Mismaloya, Jalisco* |
Darin Williams 2007 (P) |
Manzanillo, Colima* |
Derek Zoebelein 2004 (P) |
Ixtapa, Guerrero* |
Miguel Angel Morales 2012 (P) |
Mazunte, Oaxaca * |
Gustavo A. Zambrano Cabrera 2008 (P) |
Escondido Beach, Oaxaca* |
Mike Gardiner 2010 (P) |
Zapotengo Beach, Oaxaca* |
Claudia Glechner 2011 (P) |
Johngarthia planata (Stimpson, 1860) from continental mainland of Mexico and Iguana Island, Panama. A, Mexico, Oaxaca, Escondido Beach (photo by Mike Gardiner, 2010); B, Mexico, Colima, Manzanillo (photo by Derek Zoebelein, 2004); C, Panama, Iguana Island (photo by María Elena Valencia, 2006); D–E, Mexico, Nayarit, Sayulita (photos by Madeline Milne, 2013; Tania Beagley-Brown, 2007; and Daniel Brewer, 2011, respectively).
Distribution of Johngarthia planata (Stimpson, 1860): (●) island records; (□) peninsula records; (■) mainland records; (♦) locations with confirmed mainland absence of J. planata (
All mainland records of J. planata cited here refer to tourist beaches close to villages or small cities. Several photographs show individuals of J. planata foraging diurnally, running along house walls or even inside of houses and mating (Fig.
The Internet search did not reveal any photographs of J. planata from Guatemala, El Salvador, Nicaragua and Costa Rica. For the latter country, the only known records to date are those cited by
“Visitors who arrive in Sayulita during the rainy season (June-October) and decide to take a leisurely walk through the jungle towards the beach are usually quite surprised, even shocked, to find the jungle floor literally teeming with thousands of purple-and-yellow and red land crabs. Crabs seem to be foraging everywhere in the leaf litter, wildly waving their claws and scurrying away to their burrows and caves at the first apprehension of danger. Most people find them interesting and amusing, even comical, with their tubular, hyper-vigilant eyes, their defensive postures and wild gestures.”
Further photographs and accounts by
“People who have built homes in the jungle near the ocean, however, consider the all-pervasive land crabs quite troublesome. If the crabs can get into the house (they can climb walls!), they can damage clothing, books, and food. Outside of the house, they are quite hard on garden plants, shredding foliage and damaging plant roots from inside their tunnels. By the time November comes, most folks are happy to see the crabs retreat into the ground!” (
These observations demonstrate that human presence does not necessarily have a negative impact on land crabs, as suggested by
Because gecarcinid land crabs significantly influence tree recruitment by consuming seeds, propagules and seedlings, they are considered important ecosystem engineers (reviewed by
Thanks are extended to Daniel Brewer, María Elena Valencia, Tania Beagley-Brown, Derek Zoebelein and Mike Gardiner for granting permission to publish their excellent photographs of Johngarthia planata and to Daniel Brewer for providing useful information on J. planata in Sayulita. I also thank Hsi-Te Shih (Department of Life Science, National Chung Hsing University, Taiwan) for making available a copy of Manrique (1981), and Richard Hartnoll (School of Biological Sciences, University of Liverpool), David Wilcox (USA), Lyubomir Penev (Bulgarian Academy of Science, Sofia), Niamh Kilgallen (Australian Museum, Sydney) and the anonymous reviewer for providing suggestions on an earlier draft of this manuscript.