Meet Blinky, the 3 Eyed Crab
by Michael Marshall
Meet Blinky. This tiny freshwater crab has three eyes, just like its mutant fish namesake from The Simpsons. But unlike the fictional Blinky, whose deformity is blamed on nuclear waste, this crab may actually be a pair of conjoined twins, one of which is nothing but part of the head.
Gerhard Scholtz of the Humboldt University of Berlin in Germany found the Amarinus lacustris crab in the Hoteo river on New Zealand’s North Island in 2007. Instead of the usual two compound eyes, it has three. It also has a peculiar structure on its back, rather like an antenna. No animal has been seen with this particular pattern of deformities before.
When Scholtz and colleagues took a closer look, they found that the crab’s brain had not developed properly either. It was unusually small, and somewhat deformed…
(read more: New Scientist)
photo: Gerhard Scholtz, Peter K. L. Ng and Stephen Moore

Meet Blinky, the 3 Eyed Crab

by Michael Marshall

Meet Blinky. This tiny freshwater crab has three eyes, just like its mutant fish namesake from The Simpsons. But unlike the fictional Blinky, whose deformity is blamed on nuclear waste, this crab may actually be a pair of conjoined twins, one of which is nothing but part of the head.

Gerhard Scholtz of the Humboldt University of Berlin in Germany found the Amarinus lacustris crab in the Hoteo river on New Zealand’s North Island in 2007. Instead of the usual two compound eyes, it has three. It also has a peculiar structure on its back, rather like an antenna. No animal has been seen with this particular pattern of deformities before.

When Scholtz and colleagues took a closer look, they found that the crab’s brain had not developed properly either. It was unusually small, and somewhat deformed…

(read more: New Scientist)

photo: Gerhard Scholtz, Peter K. L. Ng and Stephen Moore

astronomy-to-zoology

astronomy-to-zoology:

Mictyris brevidactylus

…a species of soldier crab that occurs in Japan, China, Taiwan, Singapore and parts Indonesia. Like other soldier crabs this species will congregate in large groups during low tide and will filter the sand for small animals. When the tide moves in or if they are threatened they will bury themselves back in the the sand in a corckscrew pattern

Classification

Animalia-Arthropoda-Crustacea-Malacostraca-Decapoda-Brachyura-Mictyridae-Mictyris-M. brevidactylus

Image(s): Wayne Lee

astronomy-to-zoology

astronomy-to-zoology:

Caribbean Hermit Crab (Coenobita clypaetus)

…Also known as the soldier crab, West Atlantic crab or tree crab, the Caribbean hermit crab is a species of coenobitid hermit crab that occurs in the West Atlantic ranging from southern Florida to Venezuela. Like other hermit crabs C. clypaetus is a scavenger and feeds on fruit, plant material, carrion and feces. Coenobita clypaetus will often use shells of gastropods, usually Cittarium pica, to house and protect its soft abdomen. As the ‘crab’ grows and molts it will have to find larger shells.

Classification

Animalia-Arthropoda-Crustacea-Decapoda-Anomura-Paguroidea-Coenobitidae-Coenobita-C. clypaetus

Images: Zoofari and Tom Hadley

Patagurus rex • A Remarkable new Crab-like Hermit Crab (Decapoda: Paguridae) from French Polynesia  [2013]
Patagurus rex gen. et sp. nov., a deep-water pagurid hermit crab, is described and illustrated based on a single specimen dredged from 400 m off Moorea, Society Islands, French Polynesia. Patagurus is characterized by a subtriangular, vaulted, calcified carapace, with large, wing-like lateral processes, and is closely related to two other atypical pagurid genera, Porcellanopagurus Filhol, 1885 and Solitariopagurus Türkay, 1986. The broad, fully calcified carapace, calcified branchiostegites, as well as broad and rigidly articulated thoracic sternites make this remarkable animal one of the most crablike hermit crabs. Patagurus rex carries small bivalve shells to protect its greatly reduced pleon. Carcinization pathways among asymmetrical hermit crabs and other anomurans are briefly reviewed and discussed.

(read paper here)
reference:  Anker, Arthur & Paulay, Gustav. 2013. Zootaxa. 3722(2): 283-300.
(via: NovaTaxa - Species New to Science)

Patagurus rex • A Remarkable new Crab-like Hermit Crab (Decapoda: Paguridae) from French Polynesia  [2013]

Patagurus rex gen. et sp. nov., a deep-water pagurid hermit crab, is described and illustrated based on a single specimen dredged from 400 m off Moorea, Society Islands, French Polynesia. Patagurus is characterized by a subtriangular, vaulted, calcified carapace, with large, wing-like lateral processes, and is closely related to two other atypical pagurid genera, Porcellanopagurus Filhol, 1885 and Solitariopagurus Türkay, 1986. The broad, fully calcified carapace, calcified branchiostegites, as well as broad and rigidly articulated thoracic sternites make this remarkable animal one of the most crablike hermit crabs. Patagurus rex carries small bivalve shells to protect its greatly reduced pleon. Carcinization pathways among asymmetrical hermit crabs and other anomurans are briefly reviewed and discussed.

(read paper here)

reference:  Anker, Arthur & Paulay, Gustav. 2013. Zootaxa. 3722(2): 283-300.

(via: NovaTaxa - Species New to Science)

dendroica

astronomy-to-zoology:

Polycectus cuplifer 

…is a species of Xanthid crab that occurs in the Indo-Pacific, ranging from Madagascar and the Red Sea, west to Japan, and east to Hawaii and French Polynesia. It is covered in a dense coat of setae (britsltes) which earns it the nickname of ‘teddy-bear crab’. Like the closely related Lybia.sp P.cuplifer holds a mutualistic relationship with sea anemones. As it will hold them in its claws and use them for defense. In turn the anemone gets more acess to food due to the motility of the crab.

Classification

Animalia-Arthropoda-Crustacea-Malacostraca-Decapoda-Brachyura-Xanthidae-Polydectinae-Polydectus-P. cupulifer

Images: Scott Godwin and Wang, TC; WJ, Chen & LC, Lo

Bacteria-Eating Crabs Call Seafloor Mud Volcano Home
by Becky Oskin
A bacterial mat sounds like the festering remains of a long-ago meal, not the main course. But crabs living on a methane-spewing mud volcano were recently spotted munching on a tangled, filmy web of bacteria, providing new evidence that the deep-sea creatures rely on a mixed diet.
Researchers report today (Oct. 7) in the journal PLOS ONE that lithodid crabs, part of the lumpy, bumpy family that includes the Alaskan king crab, repeatedly snacked on bacteria offshore of Costa Rica in 2005. “As far as we know, deep-sea crabs feeding on bacterial mats were discovered only one single time before,” study co-author Peter Linke, a senior scientist at the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany, said in a statement…
(read more: Live Science)
image: GEOMAR Helmholtz Centre for Ocean Research Kiel

Bacteria-Eating Crabs Call Seafloor Mud Volcano Home

by Becky Oskin

A bacterial mat sounds like the festering remains of a long-ago meal, not the main course. But crabs living on a methane-spewing mud volcano were recently spotted munching on a tangled, filmy web of bacteria, providing new evidence that the deep-sea creatures rely on a mixed diet.

Researchers report today (Oct. 7) in the journal PLOS ONE that lithodid crabs, part of the lumpy, bumpy family that includes the Alaskan king crab, repeatedly snacked on bacteria offshore of Costa Rica in 2005. “As far as we know, deep-sea crabs feeding on bacterial mats were discovered only one single time before,” study co-author Peter Linke, a senior scientist at the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany, said in a statement…

(read more: Live Science)

image: GEOMAR Helmholtz Centre for Ocean Research Kiel

astronomy-to-zoology

astronomy-to-zoology:

Red Frog Crab (Ranina ranina)

Also known as the spanner crab, the red frog crab is a species of frog crab that is found throughout parts of the Pacific. Like other frog crabs this species is nocturnal and takes shelter in the sand during the day. Like the unrelated mole crabs the red frog crabs claws are modified for digging and allow it to bury itself into the sand easily.

Red frog crabs are edible and are fished commercially throughout its range.

Classification

Animalia-Arthropoda-Crustacea-Malacostraca-Decapoda-Brachyura-Raninidae-Ranina-R.ranina

Image: Kzhr and Benoit Lallement

Caught in the act: a crab eating frozen gas

This video was recorded during an expedition led by MBARI Senior Scientist Peter Brewer exploring methane gas deposits off the coast of Vancouver Island, British Columbia. While surveying the seafloor, the science team observed a deep sea crab interacting with naturally occurring methane which was bubbling from the seafloor. Methane hydrate, a solid ice of methane, formed when the crab attempted to ‘eat’ the bubbles.

(via: Monterey Bay Aquarium Research Institute)

The second remotely operated vehicle dive of the expedition was conducted today between Veatch and Nantucket Canyons, investigating numerous pockmark features on the upper continental slope between 500 and 650 meters above the headwall scarp of a landslide.

This video includes highlights from the dive, including lots of cool deep sea fish and other animals.

NOAA Office of Ocean Exploration and Research
Want to stay on top of what’s happening with our current Okeanos Explorer expedition? Check out our daily updates: here And be sure to tune in today (7/11/13), as we explore an area that has never been seen before, but where multibeam sonar data has detected bubbles in the water column that could indicate the presence of hydrocarbon seepage that may support chemosynthetic communities of life.  The ROV is on the seafloor, so tune in and enjoy: Ocean Explorer

Want to stay on top of what’s happening with our current Okeanos Explorer expedition? Check out our daily updates: here

And be sure to tune in today (7/11/13), as we explore an area that has never been seen before, but where multibeam sonar data has detected bubbles in the water column that could indicate the presence of hydrocarbon seepage that may support chemosynthetic communities of life.

The ROV is on the seafloor, so tune in and enjoy: Ocean Explorer

What Is a Crustacean?

by EOL staff

The Latin root, crustaceus, “having a crust or shell,” really doesn’t entirely narrow it down to crustaceans. They belong to the phylum Arthropoda, as do insects, arachnids, and many other groups; all arthropods have hard exoskeletons or shells, segmented bodies, and jointed limbs. Crustaceans are usually distinguishable from the other arthropods in several important ways, chiefly:

  • Biramous appendages.  Most crustaceans have appendages or limbs that are split into two, usually segmented, branches.  Both branches originate on the same proximal segment.
  • Larvae.  Early in development, most crustaceans go through a series of larval stages, the first being the nauplius larva, in which only a few limbs are present, near the front on the body; crustaceans add their more posterior limbs as they grow and develop further.  The nauplius larva is unique to Crustacea.
  • Eyes. The early larval stages of crustaceans have a single, simple, median eye composed of three similar, closely opposed parts. This larval eye, or “naupliar eye,” often disappears later in development, but on some crustaceans (e.g., the branchiopod Triops) it is retained even after the adult compound eyes have developed.  In all copepod crustaceans, this larval eye is retained throughout their development as the only eye, although the three similar parts may separate and each become associated with their own cuticular lens.  In other crustaceans that retain the larval eye into adulthood, up to seven optical units may develop.
  • Labrum.  Crustaceans have a lobe-like structure called the labrum anterior to the mouth that partially encloses it.
  • Head.  Crustaceans are distinguished by a five-segmented head (cephalon), followed by a long trunk typically regionalized into a thorax and abdomen.
  • Baby teeth.” Most crustaceans in their early larval stages chew their food with a unique structure called a naupliar arthrite, which is on the second antenna.  This chewing tool is lost later in development, and chewing is taken over by the mandibular gnathobase.

Crustacean characters can reveal evolutionary history both by their presence and absence. The naupliar arthrite is one of several characters that are helping researchers to untangle the evolutionary history of crustaceans and other arthropods (Ferrari et al. 2011). Though it is present in larvae of many Crustacea, several groups have lost it over the course of their evolution, and the ostracods never inherited it…

(read more: Encyclopedia of Life)

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images: T - Sally Lightfoot Crab by Victor Burolla; 2L - Florida Crayfish (Procambarus alleni) by Jan Ševcík; 2R - by Bernard Picton; 3 - Common Pill Bug (Armadillidium vulgare) by Stanislav Krejcík; 4L - Blue Crab (Callinectes sapidus) by Jere7my; 4R - Triops by BioImages - the Virtual Fieldguide (UK); B - Palinurus delagoae by Tin Yam Chan)