Chelicerata review Flashcards
Cephalothorax
A body region composed of the head and thorax fused together; prosoma
Carapace
Exoskeleton of the body; protects the cephalothorax
Compound eyes
1 on each side of the body; senses light
Simple eyes
2 small ones on the front of the body; senses light
Chelicerae
The first pair of appendages found ventrally on the cephalothorax (prosoma) followed by 5 pairs of walking legs; used for aid in the consumption of food
Pedipalps
Each of the second pair of appendages attached to the cephalothorax. They are variously specialized as pincers in scorpions, sensory organs in spiders, and locomotory organs in horseshoe crabs
Walking legs
Each of the four remaining segments contains a pair of walking legs. Used for forward motion
Chelae
Found only in males; pincers found on the Chelicerae and all but the last pair of walking legs
Gnathobases
Little spiny processes on the walking legs; helps “chew” food
Chilaria
Rudimentary appendages in between the last pair of walking legs; helps to manipulate food
What is unique about the last pair of walking legs
Since they don’t have chelae, the Chilaria help to guide food down to the mouth
Genital operculum
Site of reproduction, have genital pores on the underside of the flaps; the first of 6 flat, platelike appendages found in the abdomen of the crab
Gills
The other 5 abdominal, flaplike appendages; circulates water and pumps blood in and out of the lamellae
Lamellae
Book-gills found under the gill flaps; site of gaseous exchange between blood and surrounding water
Telson
The tail spine; used for burrowing as well as righting itself when turned over
Chelicerata
Subphylum that includes arthropods with fangs or pincers
Defining characteristics
- Absence of antennae
- Body divided into 2 distinct portions with no distinct head
- First pair of appendages, the chelicerae, on the prosoma are adapted for feeding
Body plan
2-part body plan: cephalothorax and abdomen
Prosoma
The anterior tagma of a chelicerate; cephalothorax
Opisthosoma
The posterior most tagma of a chelicerate; abdomen
Limulus
Horseshoe Crab Genus
Ecdysis
Periodic shedding of the cuticle in arthropods or the outer skin in reptiles
Exoskeleton
A body covering, typically made of chitin, that provides support and protection
Abdomen
Second of two-part body; opisthosoma
Hemocoel
The functional part of an open circulatory system that serves as the “blood cavity”
Pedipalps
