March, 2000 
SCAMIT Newsletter 
Vol. 18, No. 11 
Table A. Morphological characters which may be used to differentiate Ampelisca cristata 
cristata and A. cristata microdentata. The top three characters (in bold) appear to be the 
most reliable and easily distinguished characters. A more detailed review of both species 
is required to confirm the reliability of the secondary characters. 
Character 
Ampelisca cristata cristata 
Ampelisca cristata microdentata 
Epimeron 3, postero- 
ventral corner 
large broad tooth 
very small tooth 
Epimeron 2, postero- 
ventral corner 
acutely produced 
quadrate to rounded 
Head 
produced antero-distally 
into small “dome” (e.g., 
similar to A. careyi, but 
smaller) 
unproduced antero-distally 
Urosomal crest 
rounded on the ends, middle 
portion horizontal 
less rounded on ends, posterior 
portion higher than anterior 
Pereropod 7, basis 
squarish on bottom 
more rounded on bottom 
Gills 
narrowed distally and 
relatively small (see J.J. 
Dickinson, 1982, Fig 20, A. 
brevisimulata or A. hessleri) 
cylindrical (i.e., not narrowed 
distally) and relatively large (see 
J J. Dickinson, 1982, Fig 20, A. 
cristata) 
Compiled by Doug Deiner (MEC Analytical) and Dean Pasko (CSDMWWD). 
