Chapter 20: Crustaceans: Anatomy, Classification, and Ecology

Females posses what for sperm deposition?

Gonopores

Their appendages are:

Highly variable limbs with protopod, exopod, endopod (exhibit serial homology).

Exites and endites

Lateral and medial processes.

Epipos

Specialized exite modified as a gill

Uropod

Tail fin

In internal Features of Crustaceans they all have a---and persistent---filled with ---

hemocoel, blastocoel, hemolymph

Crustaceans have what kind of muscles?

They have striated muscles oriented in antagonistic groups called flexors and extensions.
-Flexors: draw a part towards the body
-Extensors- extend the part outward

How does gas exchange occur in small and large crustaceans?

In small crustaceans, it occurs across thin areas of cuticle.
The larger species have gills, usually internal, and very delicate.

In the open system of crustaceans the hemolymph returns to where? The valves in arteries prevents what?

Returns to venous sinuses.
It prevents backflow

Depending on respiratory pigment, Hemocyanin or Hemoglobin may be what colors?

They may be colorless, reddish, or bluish

What is the dorsal heart?

The chief propulsive organ of circulatory fluid. (the main part of the body that pumps blood or fluid through the body's circulation system).

An excretory system is a pair of?

Tubular antennal or maxillary glands depending on where they open
-Each gland has a vesicle and a spongy mass called a labyrinth; which is connected to a dorsal bladder by an excretory tubule.

Excretion of nitrogenous waste takes place where?

Across the cuticle and gills

-Their brain is a pair of ----

-It connects to the subesophageal ganglion which---

-supraesophageal ganglia. (two clumps of nerve cells (ganglia) located above the esophagus they work together to control the nervous system)
-innervates most of the "face" (nerves link the subesophageal ganglion to parts of the head area, providing sensation and control to those areas, often referred to as the "face")

Crustaceans have a well developed sense of--

Organs

Their eyes are made up of photoreceptive units called--?It is covered by a---?

Ommatidia, cornea

Why does the eye of crustaceans make a mosaic or apposition image?

Because each segment only sees part of the visual field; it forms a superposition image

Statocysts contains--

Statoliths

Crustaceans have what kind of hair?

Tactile hairs

Crustaceans have what kind of sexes that aid in lots of specialization for copulation

separate sexes

In this subphylum some of them are parthenogenetic

Subphylum Crustacea

In subphylum crustacea most of them brood their---?

eggs

In subphylum crustacea, some have direct development while others have...?

multiphasic life cycles.

The ancestral and most widely occurring larvae is known as a

Nauplius

Cuticle is...?

secreted by the underlying epidermis

Epicuticle

Outermost, lipid impregnated protein

Procuticle

bulk of cuticle, several layers

-Endocuticle:
(within the endocuticle, there's the):
-Chitinous:
and
-Uncalcified:

-The inner-most layer
-Principal layer
-Membranous layer

The intermolt phases are called what?

Instars

What is the first step in molting?

Old procuticle separates from the epidermis.

What is the second step in molting?

Still in premolt, new exocuticle is secreted as molting fluid dissolves the endocuticle

What is the third step in molting?

The old epicuticle and exocuticle is discarded.

What is the fourth step in molting?

The new cuticle is stretched and unfolded. While the endocuticle is secreted

Hormonal control stops the production of what?

Molt inhibiting hormone from the X-organ (neurosecretory cells)

Hormonal control promotes the release of what?

molting hormone from Y-organs which lie near mandibles, initiates molting.

The Androgenic glands in some males lead to the development of...?

Secondary sexual characteristics

Suspension feeders eat what?

Plankton and bacteria

Pistol Shrimp---?

Chelae can be cocked like a hammer, Second fastest animal motion recorded

Class Remipedia has about how many species?

10 species they are all from caves that enter the ocean

How many trunk segments are in Class Remipedia

there are 25 to 38 trunk segments. They are all identical, paired, and biramous swimming appendages.

In what class are the thoracic limbs all similar and the second maxillae is similar to the thoracic limbs?

Class Cephalocarida

This class is a true hermaphrodite and the eggs and sperm come through a common duct

Class Cephalocarida

What are the three orders of Class Branchiopoda?

1) Order Anostraca- fairy shrimp
2) Order Notostraca- tadpole shrimp
3) Order Diplostraca- water fleas

-Class Branchiopoda, mostly live in--?

-Many of them have complex life cycles with extensive periods of what?

-Freshwater
-Dormancy

Class Branchiopoda are very important components of--?

Food webs

Class Maxillopoda, Subclass Mystacocarida--?

Tiny, only 10 species

Class Maxillopoda, Subclass Tantulocarida

Only 12, recently described

Class Maxillopoda, Subclass Branchiura

Mostly fish ectoparasites

Class Maxillopoda, Subclass Pentastomida

Formerly a phylum, wormlike

Class Maxillopoda, Subclass Cirripedia

The barnacles, they are awesome.

-Subclass Mystacocarida are how long?
-They are distributed worldwide, but how many species?
-Where do they live?

-Less than 0.5 mm long
-10 species
-They live in interstitial spaces in sand

Subclass Copepoda are very abundant but usually how long?

Less than 2 mm in length

This subclass has a single pair of uniramous maxillipeds, four pairs of flattened, biramous, thoracic swimming appendages, and a fifth pair of legs that are reduced.

Subclass Copepoda

In Subclass Copepoda most are free living, but many are...?

Parasitic

What kind of development does subclass copepoda have?

Direct development. However, some parasitic species exhibit multiphasic life cycles

What year was Subclass Tantulocarida described and how many species are there?

Described in 1983; about 12 species

-What is the size of organisms in the subclass Tantulocarida,? and
-How many pairs of antennae do sexual females have?

-They are tiny, smaller than 0.2mm
-Sexual females have one pair of antennae

What kind of life cycle does subclass Tantulocarida have?

They have both a pathogenetic and sexual life cycle

Subclass Tantulocarida is parasitic, and the tantulus larvae penetrate the cuticle of host by a--?

Mouth tube

In this subclass, their abdomen and all thoracic limbs are lost during metamorphosis to an adult.

Subclass Tantulocarida

In subclass Tantulocarida how many segments do juveniles bear?

They bear six or seven abdominal segments

Subclass Branchiura has a second maxillae modified as what?

Suction cups

-Subclass Pentastomida has how many species?
-What are they called?

-130 species of wormlike parasites.
-Called the tongue worms

What type of parasites are subclass Pentastomida? and how long do they get?

They are mostly lung parasites of vertebrates and are up to 13 cm

Subclass Pentastomida has transverse rings that make them look---?

Segmented

This subclass has nonchitinous, highly porous cuticle, molted periodically during larval stages

Subclass Pentastomida

This subclass have five short protuberances on anterior end

Subclass Pentastomida

What kind of digestive system does subclass Pentastomida have?

Simple, straight digestive system

Does subclass Pentastomida have circulatory, excretory, or respiratory organs?

No, they do not!

In subclass Pentastomida sexes are separate and the females are usually ---?

Larger than males.

How are the larvae in subclass Pentastomida

The larvae are ovoid, tailed, with four stumpy legs.

Subclass Cirripedia has what kind of organisms?

Barnacles, plus 3 smaller orders of burrowing or parasitic forms.

Subclass Cirripedia are sessile as--?

adults

In subclass Cirripedia the cirri is extended between what--?

Between plates for filter feeding.

How does fertilization look like in subclass Cirripedia

They are mostly hermaphroditic. They have internal fertilization and become free living cyprid larvae. They attach by their first antennae, and metamorphose into adult form.

Which subclass has the longest penis in relation to body size of any animal?!

Subclass Cirripedia

This order has invaded terrestrial habitats all the way to very deep water.

Order Isopoda

Order Isopoda's have direct development, a few---? and have complex----?

A few parasitic forms, and complex life cycles.

-How many species do order Euphausiacea have? and
-How long are they?

-There are about 90 species; the krills
-3 to 6 cm long

In order Euphausiacea, the carapace is fused with all thoracic segments but unable to---?

entirely enclose their gills.

This order has no maxillipeds but has thoracic limbs with exopods

Order Euphausiacea

Order Euphausiacea are bioluminescent because of an organ called a--?

Photophore.

Order Euphausiacea is very important to marine--?

Food webs

•Thoracic segments fused with the head to form a cephalothorax

•Many have a hard covering called a carapace

Crustacean

Protopod:

The basal portion of the limb. It has two parts a basis and a coxa.

Exopod

lateral; farther from the middle of the body borne by the protopod has one to several parts

Endopod

Medial; closer to the middle of the body. Has one to several parts

Crustaceans have many similarities with--

annelids

Molting and Ecdysis is the...?

process of shedding the cuticle for growth or wear.

Hormonal control is usually initiated by what?

Environmental stimuli

In hormonal control, the androgenic glands occur in SOME males but don't occur in what?

in females.

Crustaceans feeding varies greatly. They have many specializations, but they all use the same set of what?

mouthparts

-Predators eat what?

Larvae, worms, other crustaceans, snails, and fishes.

Scavengers eat what?

detritus (trash) and dead animals

Mantis Shrimp---?

Has a specialized digit for piercing or smashing prey.

In class remipedia the antennules are biramous the maxillae and maxillipeds are prehensile and adapted for--?

Feeding

Class Cephalocarida has how many species and are how long?

Only 9 species and 2 to 3 mm long

The class has no eyes, carapace, or abdominal appendages

Class Cephalocarida

Class Branchiopoda has how many species?

10,000 species

This class has flattened, leaflike phyllopodia, or legs that serve as respiratory organs

Class Branchiopoda