GLOSSARY OF TERMS

The glossary of terms is currently incomplete. More terms will be added below as more taxon accounts are made.

  • aesthetascs: sensory hairs, usually somewhat inflated-cylindrical

  • ambulatory: not prehensile

  • appendix masculina: ♂ reproductive structures set on the endopod of pleopod 2. Often thin and elongate, can become very elaborate and fused to the endopod in some groups.

  • cephalon = head

  • basis: the basal-most segment after the coxae

  • biramous: splitting into two branches

  • carpus: the fourth main segment of the pereopod from the base

  • carposubchelate: subchelate with the palm on the carpus

  • chelate: prehensile with the main segment extending forward to form an immovable finger and the next segment(s) forming a thumb-like appendage, like a crab claw. In isopods this seems to only be present in Katianirids

  • colinear: subsquential segments continuing a straight line, not curving

  • coxae: the base of the pereopod, either fused into coxal plates

  • dactylus: the final segment of the pereopod, often tipped with claws

  • coxal plate: the fused, plate-like coxae fo Scuticoxiferans (= all isopods in our area besides Asellota and Microcerberideans) and many Microcerberideans

  • endopod: the medial segment of a biramous appendage

  • epimera: the lateral margins of the pereonal and pleonal tergites. In many isopods the pereonal coxae are fused to

  • epistome = frontal lamina

  • exopod: the lateral segment of a biramous appendage

  • flagellum: the distal portion of an antennae

  • frontal lamina: a large plate above the mouth that appears to be the fused sternites of the embryonic segments 3-4. Often nestled under or in between the antennae bases

  • ischium: the second main segment of the pereopod from the base

  • lateral: away from the midline, closer to the body margin

  • mandible: the first set of jaws, usually with an incisor (distalmost protrusion), a lacinia (middle protrusion), a row of spines, a molar (basalmost protrusion) and a palp near the base.

  • maxilla: the second and third sets of mouthparts in isopods

  • maxilliped: the fourth set of jaws in isopod. Usually has 4 main parts: a small endite, a palp of 5 or less segments, an epipod that covers the side of the mouth and a basis that covers the underneath of the mouth

  • medial: towards the midline, further from the body margin

  • merus: the third main segment of the pereopod from the base

  • nodulus lateralis: a senosory seta unique to Oniscidea, found in pairs on the pereon and sometimes cephalothorax. Position designated by the ratio between distance from the posterior border of the pereonite and the total length of the pereonite (b/c) and the ratio between distance from the lateral border of the pereonite and the total length of the pereonite (d/c).

  • oostegites: ♀ reproductive structures that hold the developing eggs and young.

  • peduncle: the basal region of an antennae. Also used in terms of the protopod

  • penes: ♂ reproductive structures derived from the coxae that sit on the posterioventral surface of the pereon

  • pereon: second tagmata of the body, contains (5-)7 segments. The appendages on the pereon segments are usually adapted for walking

  • pereonite: an individual segment of the pereon. Also spelt as pereonite

  • pereopod: an appendage of the pleon, divided into 6(-7) segments. Also spelt as pereiopod

  • pleon: the third tagmata of the body, contains up to 5 segments (often fused) and a telson. The appendages on the pleon segments are usually adapted for swimming, reproduction and respiration

  • pleonite: an indididual segment of the pleon.

  • pleopod: an appendage of the pleon, usually divided into two rami

  • prehensile: grasping, much like a hand

  • propus: the second to last segment of the pereopod from the base

  • proposubchelate: subchelate with the palm on the propus

  • protopod: the basal segme nt of the pleopods and uropods

  • rami: the segment(s) after a biramous appendage divide

  • stylet: the terminal segment of the pleopod 2 endopod of Janiroideans consisting of the fused appendix masculina and endite. Usually thin and elongate.

  • subchelate: prehensile with the main segment not extending forward and the next segment(s) forming an opposable appendage folding downwards, like the main digits in a human hand

  • sympod = protopod

  • tagmata: a collection of body segments in Arthropoda

  • unguis = claw

  • uniramous: not branching into two or more branches

Published: Jan 1, 2023
Edited: Feb, 1, 2023