Gastropoda (Chapter 13) Flashcards
Gastropoda
stomach foot; class of Mollusca
various snails (land, freshwater, marine), slugs
taxonomy - #’s, shape of whorl; shape of aperture; shape of siphon, ornament of shell
species level - modern - color pattern (rarely preserved in older)
highly diverse; sporadic fossil record
limited use of biostratigraphy - survive for long time
Gastropoda (soft tissue)
torsion: mantle cavity containing gills, anus, excretory & reproductive openings lying above the head
head, w/ eyes in some groups
very muscular foot
siphon - repiration & waste disposal - associated with anus
Gastropoda (hard tissue)
may/may not have typical spiral shell
conch - aragonite shell, typically spiral, holds mantle & visceral mass
secondary shell = operculum - typically flat, rare as fossils
radula (teeth-microfossils) - organic material (chitin); may be preserved
sinistral coiling
shell coils counterclockwise & aperture is on left
dextral coiling
shell coils clockwise and aperture is on the right
aperture
entrance or hole to the shell where organism moves in & out from
apex
oldest part of the shell, where shell starts to form
whorl
a complete turn/spiral of the shell, revolving around the axis of coiling
suture
contact between each whorl
patelliform
flat coil shell
weak resemblance to monoplacophora
type of gastropod
found on rocks & inter-tidal zone
convolute
single whorl even as getting larger in size
poorly defined apex
ex: Acteonella
bi-conical
wide, slit-like aperture
multiple narrow whorls resulted from growing allometrically
ex: Conus
digitate
shell with ornaments around aperture
one digit usually siphonal canal
ex: maple leaf murex
turbinate
shell with isometric increase in size (whorl + height)
ex: Tylostoma elevatum - Cretaceous
turreted
shell w/ high spiral conch
faster increase in whorl than in overall width
ex: Turritella nasata - Eocene
