7006

• UCREFRP Catalog Number: 7006
• Author: Gustafson, E.
• Title: Early Development, Adult Sexual Dimorphism, and Fecundity of the Razorback Sucker,
• USFW Year: 1975
• Copyright Material: NO

rieC:.i.:c!:, pU18cl~lo11S have begl...n. 'llit;; tail is oenL dOW!1 at, a. right
Ci.!l61e to '~he lJod.y axis. 'lhel'c is 11O.:il! folel. At ti-.is LoillL cIle
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.&.iJ.llc,i uU\::ts (prol.Lepiiric dU\ji;B) i.t.il.i dOl'sal aOl'ta have fU:C[;ied vel!tra.d
t.o the 11eural tuut..l and. notochord. 'the alimentary tract is lined oy
e~!'Jodt.:I'[L. and is .(18:;;.1'ly cOIIlple t;.e: stoiilad.eum and proc todeurr.. are not
yet a~parent to the eye.
SCagt~ 22: Fia ./:tuld: day 5; :LO] Dr; 5. J rru11.
'l'i'.e fin fold. has appeared on the tail and post.erior dorsum.
'1'h'3 ilGD.d :1",,;:; oegu.G to 6I'OW ou\:'wal~d from the yolk sac. .Nasal placod-
es have appeared. ~~e tail has begun to straighten. The circulatory
sistem (laS f'or'.meJ..
.s'c,J.g;~ :~Lt: CL.'cu:;"a\:.i\')~l or' riloou.: ll, iu'; 0.0 Jillil.. (Fig. 4).
'rile head. haB gl'O~~.i au t frOLl t he yolk so that the heart is now
visible wi tili1.i.l,;hd pericardis.l cavi t.y; hea:c~ has u.nLlergone fleXio!l;
SL:':u.BV eaosi s 'and 8,c1'i LWl lie above am.1.. left. of ventricle aaQ CO!lUS
a.rt;~1'iosl s. Blood..f low sequence: a,L;.ci um. - ventri cle- conus - vea-.
tra.l aor~d. - ci'&,llchial a.i'ftrents - brarlcclial efferel1ts -dorsal aor-
ta and in~ernal carotid artery - vitelli~e artery; caudal vein, post-
erior card.illal, anterior ca.rd.i.c!d.l ::J.{~<.i. vitelline vein - common card- ..
if!ai. veiIl (Duct of Cuvi~r) - SiilUS v'erwsis - atriuill. In the heart,
end.ocard.ium an.d epimyoc8..rdiuUl can be d.isti.nguished..
The pupils are visible within the eyes. Three visceral arches
(gill urc~les) are apparent. The yolk is reduced t.o a cylinder be-
low the body axis.
.Bro\'i~l pigluent e;ranules have appeared in tne choroid region of
t; i1e eye.
the eabr.yos are extrehlely motile aad some have begun to rupture
their ciw.ciol1s.

;:itage 25: Pect.oral Fi!l Rudiments: 120 hr; 6.8 mill.
,t'c:;:c toral fin Sl.alaben have appearea. posteriad and ventrad to ti-.e
6l.uli 'cOL';; v ~ssi cle::;. 'i'11e tail is sligiltly upturaeJ. (heterocercal).
'J.L...: .J':"'v,:,aJi;;um ca.n be seet}. c18arloY'. !'iyo\,o;iles are dlscernaoltl in the
;.i.d.ill. bod.y aOQve the yolk.

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