Japanese Spider Crab Macrocheira kaempferi - PowerPoint Presentation

Slide1

Japanese Spider Crab

Macrocheira kaempferi

By: Philip Mycek

Slide2

Taxonomy/Classification

Domain: Eukarya

Kingdom: Animalia

Phylum: Arthropoda

Class: Malacostraca

Order: Decapoda

Family: Inachidae

Genus: Macrochaeira

Species:

Kaempferi

Slide3

Evolution

Protostomes – the spider crab’s mouth develops before its anus

Triploblastic – they have three tissue layersSegmented bodies – the crabs body repeats in small section on its underside Eucoelomate – They have coeloms lined with mesodermBilaterally symmetrical – like all crabs, they can be divided evenly down the middle

Slide4

Evolution (continued…)

Japanese spider crabs are thought to be able to live up to 100 years, so they may have the longest lifespan of any crab

There have been spider crab fossils discovered that date back millions of yearsBecause of how vulnerable they are to many predators including octopus and stingrays, spider crabs often decorate themselves in order to camouflage from said predators

The decorator crab is another crab that decorates itself in order to camouflage from predators

Slide5

Name Origin

The Japanese spider crab’s scientific name is

Macrochaeira kaempferi. This originates from a combination of words from the Greek language: Makros, which means big or long and cheir which means hands or arms. This name refers to the spider crabs noticeably long appendages. Their Japanese name, Taka-

Ashi-Gani, translates to “tall legs crab.”

タッカー足ーがに

Japanese spelling

Slide6

Reproduction

Japanese spider crabs reproduce via internal fertilization

While females often lay up to 1.5 million eggs, only a few surviveEggs take roughly 10 days to hatchMating is seasonal, happening during early spring, between January to MarchThey migrate to shallower waters during mating seasonThe male inserts a spermatophore, into the female as their abdomens push against one another

Male and female spider crab mating

Slide7

Growth

Like other crustaceans, Japanese spider crabs outgrow their exoskeletons. They molt, removing their old shell before growing a new one. While the actual molt takes as little as 15 minutes, the entire process begins weeks in advance with the crab producing enzymes to begin separating from the exoskeleton.

Spider crab molting old exoskeleton

Slide8

Growth (continued…)

They often eat the remains of their old shell after molting, as they’ll eat almost any dead decaying matter they can find

The old shell looks very much like a dead crab, however there are holes where the eyes used to beSpider crabs are very vulnerable during this time, as predators such as stingray can eat their soft unprotected bodies with ease

Young spider crab post molt

Slide9

Respiration

The Spider Crab has an open circulatory system

The blood oxygenizes when water runs over the gills and the gills absorb oxygen from the waterAfter that, the heart pumps the blood around the body for the cells to be oxygenated, so that they can carry out cellular respiration

Slide10

Digestion

Japanese spider crabs are omnivorous and scavenge for dead decaying matter on the seafloor

They feed on shellfish, algae, plants, mollusks, and small fishTheir chelipeds (pincers) can tear up meat and open shells in order to fit food in their mouths

Slide11

Locomotion

Spider crabs move using their long legs along the ocean floor

They lack the ability to swim

Because their limbs are very delicate and poorly attached at the joints, they can easily break off

A 2001 study found that 74% of them are found missing at least one limbThey can live with up to three missing limbs

Slide12

Excretion

All arthropods, including spider crabs excrete waste through Malpighian tubules that carry waste product to the posterior end of the crab, in which it is emptied at the anus

Generally, crabs digest nitrogenous waste through diffusion across their antennal gills

Slide13

Habitat

They’re found mainly in the Pacific side of the Japanese islands, Honshu and Kyushu

They live at an average depth of 200 metres below sea levelYounger crabs generally live in shallower, warmer waterThe Japanese spider crab has been found as far south as Su-ao, in Eastern TaiwanThey thrive in temperatures around 10° C

Slide14

Anatomy

While it possesses four pairs of legs and often crawls along the ocean floor, the spider crab is unable to swim due to a lack of rear legs

The spider crab’s slow moving front claws, called chelas, are relatively weak and can only be used to hunt down small prey

Slide15

Anatomy (continued…)

The spider crab has the largest leg span of any arthropod, with a total length of up to 3.8 metres

Despite this, the length of the crab’s actual body is only about 38 cm longThey have 8 legs total, with an additional 2 arms used for feedingTheir long legs give them an arachnid-like look which has resulted in their common name

Slide16

Culture

Because of it’s large size, several myths have been associated with the spider crab. Japanese folk tales describe a spider-like sea creature that would pull fishermen out of their boats to the seafloor.

Illustration of a sailor fighting off a spider crab

Slide17

Culture (continued…)

Because of their rarity and appealing taste, spider crabs are considered a delicacy in many places in Japan

Because of declining populations, laws have been established in Japan which prohibit fishermen from harvesting spider crab, from January through April, which is during typical mating season, when crabs migrate to shallower depths to reproduce. (Freeman, 2010; Okamoto, 1993)

Slide18

Aboriginal Culture

While the Japanese spider crab does not live anywhere outside of Asia, many Japanese villages once relied partially on them for nutrition

Non-spider crabs are reported to have been consumed by many coastal Indigenous Peoples who had access to themThese Indigenous groups most notably include: Coast Salish, Squamish, and the Nootka (Nuu-chah-nulth) of Vancouver Island

In yellow: areas in which crab consumption amongst

Indigenous groups is high

Slide19

Aboriginal Culture (continued…)

A large part of Aboriginal culture includes the value that is put on different animals. Aboriginal tribe members learn from a young age to appreciate the different things nature gives them, and in return, try to waste as little of those things as possible. This is why Aboriginal people’s are very against the overhunting of different animals. This includes one of their food sources: the crab. If we hunted species of crab to extinction, many groups, Indigenous or otherwise, would lose an important source of food/income.

“All my relations”

Aboriginal greeting used in recognition of the principles of harmony, unity and equality. One can argue it serves as a foundation for First Nation’s values.

Slide20

Conclusion

With the largest leg span of any arthropod, the Japanese spider crab fascinates millions of people across the globe. Relatively harmless creatures and an apparent great meal, conservation efforts have been made in Japanese legislation in order to protect it. The Japanese Spider crab is a mostly harmless animal, and despite what some legends may speak of it, they remain a fragile and largely misunderstood creature. They are often referred to as “creepy” and “gross,” while being quite harmless to humans. The future of the Japanese spider crab is uncertain; however, one can easily argue that fascination with this incredible creature will not die out anytime soon.

Slide21

Works Cited

Allan, Laura. “11 Facts About Japanese Spider Crabs That Will Keep You Up At Night.”

Ranker,

Entertainmenthbo Maxmoviescelebritycomedyhorrorbehind

the Scenesnostalgiawatchworthymusicrockhip

Hopcountrymetalpop

Musicsingersalbumsmusic Historynerdygamingcomicsanimecartoonstoystechspacesciencesportsnflsoccernbabaseballhockeycollege Sportscombat Sportsathleteslivingbeautyfashionfamilyrelationshipspetshomecareerautomotivehistorypoliticsworld Historyus Historyroyaltywarmysterieshistorical Figuresancient Historyculturearttravelbooksdeep ThoughtsLGBTQastrologyfunnysocial Mediafoodcookingbeverageslibationsfast

Foodsnacksrestaurantshealthy Eatingsecret Menu ItemschannelsWatchworthyTotal NerdWeird HistoryButton MashGraveyard

ShiftAnime

UndergroundWeird

NatureUnspeakable

CrimesWeirdly

Interesting, www.ranker.com/list/japanese-spider-crab-facts/laura-allan.

Baseel

, Casey. “Believe It or Not, This Isn't a Map of Japan (Though It Sort of Is).”

SoraNews24

, 12 Apr. 2018, soranews24.com/2018/04/12/believe-it-or-not-this-

isnt

-a-map-of-japan-though-it-sort-of-is/.

Breyer, Melissa. “10 Of the Largest Living Creatures in the Sea.”

Treehugger

, www.treehugger.com/largest-living-creatures-sea-4859211.

Cornell, Brent. “

Malphigian

Tubules.”

BioNinja

, ib.bioninja.com.au/higher-level/topic-11-animal-physiology/113-the-kidney-and-osmoregu/malpighian-tubules.html.

Horton, Andy.

BMLSS: Crustacea: Moulting, Changing Shells

, www.glaucus.org.uk/Ecdysis.htm.

Slide22

Works Cited

“Japanese Spider Crab Facts for Kids.”

Japanese Spider Crab Facts for Kids, kids.kiddle.co/

Japanese_spider_crab#:~:text=Japanese%20Spider%20Crab-,The%20Japanese%20spider%20crab%20has%20the%20largest%20leg%20span%20of,meters%20(5%20ft)%20long. “Japanese Spider Crab,

Macrocheira

Kaempferi

.”

Cardiovascular

, thecardiovasculars.weebly.com/japanese-spider-crab-macrocheira-kaempferi.html#:~:text=But%20crabs%20have%20an%20extensive,to%20carry%20out%20cellular%20respiration. “Japanese Spider Crab.” Smithsonian Ocean, 18 May 2018, ocean.si.edu/ocean-life/invertebrates/japanese-spider-crab. “Japanese Spider Crabs: All About The Giant and Scary Crabs.” Discovering All Marine Species, 1 Jan. 2019, ourmarinespecies.com/c-crabs/japanese-spider-crabs/. Kasher, Netta. “Bilateral Symmetry of A Crab (Organism's Symmetry Illustration).” Dribbble

, dribbble.com/shots/5180901-Bilateral-Symmetry-of-A-Crab-Organism-s-Symmetry-Illustration.

Slide23

Works Cited

Kids Discover. “Japanese Spider Crabs: Twelve Feet of Legs.”

Kids Discover, 9 Dec. 2016, kidsdiscover.com/quick-reads/

japanese-spider-crabs-twelve-feet-legs/#:~:text=So%20it's%20no%20surprise%20that,(left%20by%20human%20predators). Listerious

. “21 Creepy Facts About The Japanese Spider Crab.” Listerious

, 28 Nov. 2020, www.listerious.com/facts-about-the-japanese-spider-crab/.

"Okamoto, K. (Shizuoka-ken. Government Office (Japan)).". “Limb Loss in the Giant Spider Crab

Macrocheira

Kaempferi.” AGRIS, 1 Jan. 1970, agris.fao.org/agris-search/search.do;jsessionid=D172B304C936E95971FD100C57C88BF8?request_locale=es&recordID=JP2003000209&sourceQuery=&query=&sortField=&sortOrder=&

agrovocString=&advQuery=¢erString=&enableField=. Riebel, William. “Macrocheira

Kaempferi.” Animal Diversity Web

, animaldiversity.org/accounts/

Macrocheira_kaempferi

/.

“Slender Decorator Crab •

Oregonia

Gracilis

.”

Biodiversity of the Central Coast

, www.centralcoastbiodiversity.org/slender-decorator-crab-bull-oregonia-gracilis.html.

Slide24

Works Cited

Thomas. “Japanese Spider Crab Moulting.”

Japan Reference, 12 Feb. 2019, jref.com/journals/japanese-spider-crab-moulting.1130/.

Tracyn. “Japanese Spider Crab: The Dallas World Aquarium.” The Dallas World Aquarium | #DWAZOO

, 2 Dec. 2013, dwazoo.com/animal/japanese

-spider-crab/.

“Traditional Animal Foods of Indigenous Peoples of Northern North America.”

Crabs | Traditional Animal Foods of Indigenous Peoples of Northern North America - Animals - Marine Invertebrates - Crustaceans

, traditionalanimalfoods.org/marine-invertebrates/crustaceans/page.aspx?id=6518. Wagamese, Richard. “Wagamese: 'All My Relations' about Respect.” Kamloops Daily News, 21 July 2014, www.kamloopsnews.ca/opinion/columnists/wagamese-all-my-relations-about-respect-1.1237759#:~:text=%22All%20my%20relations%2C%22%20means,the%20real%20and%20the%20living. Wicksten, Mary K. “A Review and a Model of Decorating Behavior in Spider Crabs (Decapoda, Brachyura, Majidae).” JSTOR

, www.jstor.org/stable/20104855?seq=1. Wolf, Michael. Japanische Riesenkrabbe (Macrocheira Kaempferi). 11 May 2006.

Slide25

Works Cited

“

タカアシガニの脱皮6

時間全記録！- The Giant Spider Crab Sloughed off Old Skin.” Enoshima

Aquarium Official Channel, www.youtube.com/watch?v=VgCDcobtZHs&feature=emb_title.