Marshall Islands Brachyuran Crabs

This page links to photos of Brachyuran crabs we have seen in the Marshall Islands. Many of our species remain unidentified and many names we do have are uncertain. Much of crab taxonomy depends upon close examination of the numerous appendages, something that is not easily done through in situ photographs of the living animal. We welcome corrections or suggestions at uwkwaj@yahoo.com. The Brachyurans constitute the larger of the two main groups of crabs at Kwajalein. The other group. the Anomurans, consisting of hermit crabs, porcelain crabs and squat lobsters, are covered elsewhere on this site. Like the Anomurans, we show only a sampling of the Brachyuran species found in the Marshalls. A checklist of crabs from Enewetak Atoll based on multiple collections over the years is presented by Garth et al (1987) and records some 291 species, which is considerably more than we cover here. No doubt there are many more to be found even beyond the Enewetak checklist.

Measurements were not taken in the field and animals were not collected, so any sizes given are very rough eyeball estimates often based on distant memories, and are provided only as a general guideline of what to look for. Unless otherwise noted, our crab measurements are estimated widths of the carapace, not including the appendages, which may be much longer. The thumbnails below link to pages with additional, larger photographs.

Acidopsidae


Parapilumnus cristimanus



Aethridae

From photos in references and on the web, specimens of Aethra, or potato chip crabs, appear to be somewhat variable in texture, and sometimes even in color. We have sorted the ones we see into different forms and tentatively assigned some names based on what we see in the literature. However, it is possible that all of these are variations of one or two species.


Aethra edentata


Aethra scruposa


Aethra cf scruposa


Aethra sp. 1

Aethra sp. 2

Drachiella angulata

Calappidae

These are the box crabs. They live in sandy areas, buried by day and often out on top of the sand at night. Powerful pincers are used to break up mollusk shells.


Calappa calappa


Calappa calappa

Calappa calappa


Calappa cf calappa


Calappa hepatica


Calappa torulosa

Carpiliidae


Carpilius convexus


Carpilius maculatus

Crossonotidae


Crossonotus cf spinipes


Cryptochiridae


Hapalocarcinus marsupialis


Hapalocarcinus marsupialis

Dairidae


Daira perlata


Domiciidae


Cherusius triunguiculatus


Domecia glabra

Domecia cf hispida


Domecia sp. 1

Dromiidae

The rear pair of legs of dromiid crabs is situated so that they can be used to hold something over the crab's shell, often a sponge but sometimes tunicates, clumps of soft coral, algae or any other item that may help to shield the crab from predators. Because there are numerous species in the family and critical taxonomic details of the crab are difficult or impossible to observe without a specimen in hand, most of our identifications are tentative and should not be taken as positivie IDs.


Alcockdromia fallax

Ascidiophilus cf caphyraeformis

Cryptodromia cf hilgendorfi

Cryptodromia? sp. 1

Dromidiopsis cf lethrinusae

Dromidiopsis cf tridentata

Mclaydromia dubia

Stebbingdromia plumosa

Takedromia? sp. 1


Dromiid sp. 2


Dromiid sp. 3

Dromiid sp. 4


Dromiid sp. 5

Dromiid sp. 6

Dromiid sp. 12

Dromiid sp. 13

Dromiid sp. 14

Dromiid sp. 17

Dromiid sp. 18

Dynomenidae


Dynomene praedator


Dynomene cf praedator

Hirsutodynomene spinosa

Epialtidae


Huenia brevifrons


Huenia pacifica

Huenia sp. 1


Huenia sp. 1

Hyastenus? sp. 8

Hyastenus or Naxioides sp. 1


Hyastenus or Naxioides sp. 2

Menaethius monoceros

Menaethius orientalis

Menaethius orientalis

Micippoides angustifrons

Simocarcinus sp. 1

Simocarcinus sp. 2

Simocarcinus sp. 3

Thusaenys sp. 1

Tylocarcinus cf dumerilii

Tylocarcinus styx

Tylocarcinus sp. 1

Xenocarcinus conicus

Xenocarcinus conicus

Xenocarcinus conicus

Epialtidae sp. 2

Epialtidae sp. 3

Eriphiidae


Eriphia scabricula


Eriphia sebana

Euryplacidae


Platyozius laevis


Gecarcinidae

Land crabs.


Gecarcoidea lalandii


Geograpsus crinipes

Grapsidae


Grapsus tenuicrustatus


Pachygrapsus planifrons

Planes minutus

Inachidae


Achaeus sp. 1


Achaeus sp. 3

Camposcia retusa


Chalaroachaeus curvipes

Oncinopus sp. 1

Oncinopus sp. 2

Oncinopus sp. 3

Oncinopus sp. 4


Oncinopus sp. 5

Oncinopus sp. 6

Oncinopus sp. 7

Oncinopus sp. 8

Oncinopus sp. 9

Oncinopus sp. 10

Oncinopus sp. 11

Leucosiidae


Alox sp. 1


Alox sp. 2


Heteronucia fujitai

Heteronucia cf perlata

Heteronucia spinifera

Heteronucia venusta

Nucia speciosa


Nucia sp. 1

Raylilia coniculifera

Raylilia sp. 1

Urnalana cf angulata

Urnalana purarensis

Majidae


Micippa cf platipes

Micippa cf platipes

Micippa sp. 2

Micippa sp. 3

Micippa? sp. 4

Schizophrys aspera

Ocypodidae


Ocypode ceratophthalmus


Ocypode cordimana

Oziidae


Lydia annulipes


Palicidae


Exopalicus maculatus


Pseudopalicus sp.

Palicidae sp. 1

Parthenopidae


Aulacolambrus hoplonotus


Daldorfia horrida

Daldorfia cf leprosa


Daldorfia? sp. 5

Furtipodia petrosa

Pseudolambrus? sp. 1

Rhinolambrus pelagicus

Rhinolambrus pelagicus

Rhinolambrus rudis

Thyrolambrus efflorescens

Percnidae


Percnon affine


Percnon guinotae


Percnon planissimum

Pilumnidae


Actumnus digitalis

Echinoecus pentagonus

Gonatonotus nasutus

Harrovia albolineata

Harrovia sp. 1

Lophoplax vermiculata


Lophoplax? sp. 1


Pilumnus longicornis


Pilumnus cf longicornis

Pilumnus cf novaezealandiae

Pilumnus taeniola

Pilumnus vespertilio

Tiaramedon spinosum

Viaderiana quadrispinosa

Plagusidae


Plagusia immaculata


Plagusia squamosa

Portunidae

Swimming crabs.


Atoportunus gustavi

Caphyra tridens

Caphyra sp. 1

Carupa tenuipes

Catoptrus nitidus

Charybdis natator

Gonioinfradens paucidentatus

Gonioinfradens? sp. 1

Goniosupradens hawaiensis

Libystes cf nitidus

Lissocarcinus laevis

Lissocarcinus orbicularis

Lissocarcinus orbicularis

Lissocarcinus orbicularis

Lissocarcinus orbicularis

Lupocyclus quinquedentatus

Monomia petrea

Thalamita coeruleipes

Thalamita cf picta

Thalamita cf picta 2

Thalamita prymna

Thalamita pseudopelsarti

Thalamita sp. 1

Thalamita sp. 2

Thalamita? sp. 4

Thalamita sp. 5

Thalamita sp. 6

Thalamita? sp. 7

Thalamita? sp. 9

Thalamita? sp. 10

Thalamita? sp. 11

Thalamitoides cf spinigera

Trionectes spiniferus

Xiphonectes longispinosus

Xiphonectes stephensoni

Xiphonectes sp. 1

Xiphonectes sp. 2

Portunid sp. 1

Portunid sp. 6

Portunid sp. 17

Portunid sp. 25

Tetraliidae and Trapeziidae


Tetralia glaberrima

Tetralia nigrolineata

Tetralia rubridactyla


Tetralia sp. 1


Tetraloides heterodactylus

Tetraloides nigrifrons


Trapezia bidentata

Trapezia formosa

Trapezia guttata

Trapezia rufopunctata

Trapezia tigrina

Trapezia sp. 3

Trapezia sp. 4

Trapezia sp. 5

Xanthidae


Actaea polyacantha


Actaea polyacantha

Actaea polyacantha

Actaeodes tomentosus

Atergatopsis germainii

Atergatopsis germainii

Atergatopsis germainii?

Atergatis floridus

Atergatis granulatus

Banareia? sp. 1

Chlorodiella cf nigra

Chlorodiella sp. 1

Cyclodius ungulatus

Cymo adnreossyi

Cymo melanodactylus

Cymo quadrilobatus

Cymo sp. 1

Etisus cf anaglyptus

Etisus cf anaglyptus

Etisus demani

Etisus demani

Etisus demani?

Etisus demani?

Etisus dentatus

Etisus cf dentatus (juv)

Etisus electra

Etisus laevimanus

Etisus splendidus

Etisus splendidus (juv)

Etisus utilis

Etisus utilis (juv)

Etisus sp. 1

Euxanthus huonii

Hypocolpus pararugosus

Lachnopodus? sp. 1

Liomera cinctimanus

Liomera cf cinctimanus

Liomera monticulosa

Liomera rubra

Liomera rubra (juv?)

Liomera stimpsonii

Liomera tristis

Liomera tristis

Liomera sp. 1

Liomera sp. 2

Lophozozymus dodone

Lophozozymus dodone

Lophozozymus edwardsi

Lophozozymus incisus

Lophozozymus pulchellus

Luniella pugil

Luniella cf spinipes

Lybia caestifera

Lybia tessellata

Menippe cf rumphii

Neoliomera cf insularis

Neoliomera cf intermedia

Neoliomera richtersii

Neoliomera striata

Neolioxantho asterodactylus

Palapedia serenei

Paractaea rufopunctata

Paractaea sp. 1

Paractaea sp. 2

Paractaea sp. 3

Platypodia pseudogranulosa

Platypodia semigranosa

Platypodia sp. 1

Platypodia? sp. 2

Pseudoliomera hellerii

Pseudoliomera speciosa

Soliella flava

Tweedieia laysani

Tweedieia laysani

Tweedieia laysani

Tweedieia laysani

Xanthias lamarckii

Xanthias lamarckii

Xanthias cf lamarckii

Xanthias latifrons

Xanthias punctatus

Zosimus aeneus

Zosimus maculatus

Xanthid sp. 3

Xanthid sp. 12

Xanthid sp. 31

Xanthid sp. 37

Xanthid? sp. 42

Xanthid sp. 44

Xanthid sp. 48

Xanthid sp. 48

Xanthid sp. 48

Xanthid? crab sp. 56

Xanthid sp. 59

Family uncertain


Crab sp. 6

Crab sp. 7

Crab sp. 8

Crab sp. 9

Crab sp. 10

Crab sp. 11

Crab sp. 12

Crab sp. 16

A few crabs from other areas:


Hawaiian Islands

Indonesia (Bali)

Indonesia (Lembeh)

Philippines (Anilao)

We thank the knowledgeable people in the Facebook Crustacean Identification Group for suggestions on several of these species.

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