All larvae have 26 myomeres
(6-8 preanal myomeres
during the preflexion stage, shifting to 10-11 during the postflexion stage).
Species Trunk myomeres
Circumoral teeth American Brook Lamprey 64-75 Unicuspid Northern Brook Lamprey 47-56 Unicuspid Silver Lamprey 47-55 Unicuspid Chestnut Lamprey 49-56 Bicuspid Species Dorsal fin Lateral line pores American Brook Lamprey Separate None Northern Brook Lamprey Connected None Silver Lamprey Connected Black Chestnut Lamprey Connected Black Table 2.--Lampreys collected and preserved by biologists of the City of Elkhart Public Works and Utilities during 1998-2012.
The distribution is not symmetrical between left and right sides; they are separated by 1 to 4 myomeres
in dorsal view.
lineatus since in this sample there is a group of melanophores between myomere
9 to 13 as the main characteristic, and for Diapturus peruvianus because of the three spots displayed in the dorsal margin of the intestines from the insertion of the pectoral fin to the anus (Jimenez et al.
Larvae of northern sculpin have 35-36 myomeres
, pelvic fins with one spine and two rays, a bony preopercular shelf, four preopercular spines, 3-14 irregular postanal ventral melanophores, few, if any, melanophores ventrally on the gut, and in larger specimens, two rows of ctenoid scales directly beneath the dorsal fins extending onto the caudal peduncle.
. In addition, during the later stages of development, X.
3, A and B) showed a distinct pattern of 12 to 23 small postanal melanophores serially arranged, about one per myomere
, along the ventral midline.
Because of the difficulty in accurately counting myomeres
in transforming clupeids (Hettler, 1984; Ditty et al., 1994), we chose to count total vertebrae and use the number of postdorsal and preanal vertebrae instead of postdorsal and preanal myomeres
as a potential diagnostic character.
There are 31-35 myomeres
. The number of vertebrae in the cleared and stained larvae is 34-35 (11-12 + 22-24).
These are distinguishable from hemiramphid larvae by their higher myomere
count (62-70), greater number of principal caudal-fin rays (16-17), presence of dorsal and anal finlets, and much heavier pigmentation (Bruce and Sutton, 1998; Trnski et al., 2000).
Melanophores on the snout disappeared, whereas clusters of melanophores on the anteriodorsum of the trunk (second myomere
), anteriordorsum of the caudal area (17th to 21st myomere
) and posteriodorsum of the caudal area (30th to 39th myomere
), as well as on the anterio- and midventral edge (14th to 26th myomere
), posteroventral edge (28th to 39th myomere
), and lateral midline (posterior to the 13th myomere
) of the caudal area began to shrink (although they were still large [Tables 2-5]).
width measurements taken from formalin preserved larvae were used in the shrinkage correction model.