Arthropod week 10

Thecostraca larvae order

nauplius, cypris (face down), juvenile, adult

thecostraca reproduction

mainly internal fert with long penis

thecostraca feeding

active filter feeders, cirri create current to increase particle capture

Malacostraca class non planktonic

isopod, amphipod, stomatopod, decapod

Isopod order walking legs

14

isopod anatomy

compressed dorsoventrally, 2 antennae pairs on head

pleon in isopods

equivalent to abdomen region, 5 segments called pleonites, host the pleopods (respiration) on ventral side

pereon in isopods

equivalent to thorax, 7 pairs of pereopods (walking legs) with 7 pereonites (segments)

isopod reproduction

internal fertilization, males use pleopods to transfer sperm directly, eggs develop in marsupium

isopod juvenile

mancae (no true larval stage)

Amphipod shape

compressed laterally (hot dog)

amphipod pereon

had 7 pairs of pereopods and 7 pereonites

amphipod pleon

6 pleonites and pleopods (dont host gills like ispods)

coxae

plates that connect pereopods to the pereon (hosts gills), more present in amphipods than isopods

gnathopods

specialized feeding and mating pereopods (in amphipods)

amphipod reproduction

external/internal, males grasp females with gnathopods (praecopula), females carry eggs in marsupium until they hatch into juveniles

Amphipod groups

Gammarid, caprellids, hyeriids

Gammarid suborder

laterally compressed, benthic

caprellid family

skeleton shrimp, stick like body

hyeriid suborder

planktonic, round, often transparent

gammarid grazing

heavily graze on epiphytes (primary producers that grow on other primary producers)

Stomatopod order

mainly benthic, usually make their own burrows and caves

paired penes/genital split

internal fertilization, male dances, female broods until eggs hatch

maxillipeds

handling food and communication (stomatopods)

stomatopods pereopods

6 walking legs

stomatopods pleopods

used for swimming (10), host gills

raptorial appendages

smasher and spearer (stomatopods)

abdomen and telson (stomatopods)

protection

stomatopods nervous system

complex, 12-16 types of photoreceptors

Zoea stage

stomatopod larvae, shorter abdomen

alima stage

stomatopod larave, longer abdomen with wide telson, longer antennae, more developed raptorial appendages

erichthus stage

stomatopod larvae, more developed pleopods

decapod groups

10 walking legs

Anomura infraorder ex

hermit crabs, mole crabs, squat lobsters, porcelain crabs

anomura anatomy

4th or 5h pair of pereopods very small, sometimes asymmetrical abdomen, 2 distinct chela

anomura reproduction

brooders with pseudo external fert

caridean infraorder

true shrimp

caridean anatomy

thin, laterally compressed carapace, long pleopods for swimming, 4 chelipeds/chela

caridean reproduction

brooders with pseudo external fert

panaeid family

prawn shrimp

panaeid anatomy

thin/cylindrical carapace, long pleopods for swimming, 6 chelipeds/chela

panaeid reproduction

external fert/broadcast spawners

astacidea infraorder

true lobsters

astacidea anatomy

cylindrical and heavy carapace, short pleopods, 2 chelipeds/chela

astacidea reproduction

brooders with pseudo external fert

achelata infraorder

spiny/slipper lobsters

achelata anatomy

cylindrical, heavy, and spined carapce, short pleopods, no chelipeds/chela

achelata reproduction

brooders with pseudo external fert

brachyura infraorder

true crabs

brachyura anatomy

broad/flat carapace with short abdomen, pleopods for brooding, 5th pereopod could be modified for swimming, 2 chelipeds/chela (can be distinct or similar)

brachyura reproduction

brooders with internal fert