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<br />
<br />Figure 36. Mexican stonerollerlrodapiedras mex/cano, 93
<br />mm in total length, lrom Rucker Canyon. Arizona This
<br />species is rare In the Unlled States. but remains locally
<br />common 10 MexICo. It IS Ilsled as a speCies 01 special
<br />concern.
<br />
<br />Mcxlcan slOnerilllers (FI~. _~6) h.J\'t- c.lrtil.I":lnous
<br />sheaths on theIr laws for Slr;lrln~ f:ncrustln~ ,llg,le
<br />from stones Jnd lltl1t~r soJJd sub.,trates, LMgC adult,>.
<br />whl(h may .iHJin lengths of 15 cm or mort'. JJ\"t' In
<br />pools CliCept In breeding se.lstln. youn~ trtquent
<br />flfIles and runs. BreeJlnF m;iles ntH ,)nly Jlspl.lY
<br />b>fI~ht colors on the b,)dy ,lnd tIns. but Also develop
<br />,In en[ar,l.:ed hr-ad Jnd humpl-J hack .lnd stremI'.
<br />shHp ruberdes On till:" .;noUl ,lnd beJ.:!_ Tbese
<br />tubercles He LJSl'd In Cllmna[ ht"[ween males.
<br />s[lmulatJn~ and ~lIiJlnF females. and for dlhFlOF.
<br />The (trm "swnerollt'f' comr-s from tht" mo\'t"mt"nt
<br />of gra\"t~l by .J male durinI' nnt eliC.iViHlOn. SWnt's
<br />are pushed ,lb'lUe Wl[!l the ht'JJ Jnd carnt"d In the
<br />mouth. which rl'sults In an elon!:ate depreSSIOn on
<br />nftles that IS JCtlvely defended JfalnS[ other n1Jll'.~.
<br />FemJJes entc'r tbt' deprt'sslon ,1nd spJwn. dH:n th,-
<br />m,de prlJ[nts [he egp until hatchm,(:.
<br />,\ble ornatc mlllnows (Fig_ ~"'l.He almost as
<br />speu;lcular as ~1('xI(J.n sroner,)I!r-rs In [h.1t their
<br />heads become swnllen ,InJ ClIHn-J hy coarse
<br />ruboercles. The speut.s IS. hllwevc:r. much smaller In
<br />siz(.', rarel\" JChle\"ln~ more th,lO ""'c, mm lonl.:, and
<br />develops .i,uk f:,IUIstl black cplorJ.t1lw on [h~ hody
<br />when In breedln}.: Londltllln. The fins also Ul-
<br />Jukt"ned. O\t"rlyinf .I milky whul'_ (lp,lque
<br />pigmentatIOn dut lies deep In tissues of the Iln
<br />membranes. The 9:.,1.:S .HC dernsl[l-d ,In thl- undcrside
<br />of stom-s In shallow Watcr and ngl'h1usly ~Idended
<br />b\. the mak
<br />LfltJ~l'r !i\'eu ."'UCkl'O .Hld .\tinnou ,~.-Dl-St.rt
<br />!T:'')llnt~IO-Su(k\-r .1nJ Sonorall sucker "IJulrdl' Jow".mJe
<br />(Figs. ;g-.,91 to,!o:l,ther Cl,mprlst" tht most comnwn
<br />larger fishcs rem,llmn~ In the lower Coloradu basin
<br />80th occupr hud-bottomed h;lbuars from ;00 w
<br />2000 m ele'I'J.tlOn. Adults of both lln" In plll1ls. With
<br />the former commonly monn,!.: to SWIft nfjles .ind
<br />runs to feed ,It OI~!H. Youn~ mnumJIO-suekers
<br />
<br />
<br />FIgure 37. Ornate minnow/sardinsta ornata. male (above)
<br />and female (below) (56 and 55 mm In lo!al lenglh.
<br />respectIvely), from Rio Papigochic, Chihuahua. Omale
<br />minnows are Widespread In a number 01 river baSins in
<br />MeXICO. and may represent a complex 01 species.
<br />
<br />
<br />.Ihundanrly Inh,lbn rlftlt.s throughout th" day, feeding
<br />on encrustln}.: algae scr,lped {rom stones with well-
<br />dcn.loped (artlla~lnuus she.Hhs on [he jaws (Fi~. .lD).
<br />'l\)ung Sonllroln Slickers .llso may be on rimeS, but
<br />more tYrlcall~. !tve In runs .1Ild quieter eddies. Ther
<br />feed on .1quJ,tit: InSCct 1.uv<\c Jnd other Im'enehutcs.
<br />,lOd only rarely on pLwts. 8\l(h speCies sp.iwn In
<br />sprln~ on rimes. where adults cnn~regate In J.1t~e
<br />numbers. Spawnin~ IS t~rlcdly of one l.ir~er f{'m,lle
<br />and two or more smaller males. A depreSSIOn in the
<br />h(IUOm IS tIHmt'd by later.d nwvemenrs of the
<br />t"t'ma[e's bolldy, and adheslH l'KCS are nUfled In loo<,{'
<br />,ctJ\'t'ls. Thr-y de"dup [\1 h,itt:h In .I few Jays, The
<br />Little COhlf.ldo sllt:kt.r (Fig. .\ II and tflbutary
<br />poruJJtwm of blur-head mountaln.sllckers h3\.e
<br />similar eLolopes In sue.lms of the Little Colorado
<br />Rlvcr baSin.
<br />[n [ht'" RIO YaquI baSin. Y,lqUI suckers:mdtJ/o{r
<br />Y.Jqkl tFI,L:. -i2l .lfe wldl'sprc:ad from the lowcst
<br />elevatIOns ion ,Ind near the river., delta) to higher
<br />than :?(lOo m In mOuntain stn.,lms The\" resemhle
<br />SOllMan Slickers hoth ecol\),L:IC;llly JnJ ~orpholog.
<br />lC"ally. ,Ind m.I~. rl'preSl-m only J suhspecies of th,l(
<br />GilJ RI\'er fl,rm. Three mher speCies of suckers
<br />In the RIO YJqui h.lsln .dl tr-nd to be at 11I~her
<br />e1r-vatlOn: Leopold suckt'"r and Ri\1 Grande
<br />
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<br />01102
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