Primamalario Picis

《作文:PrimamalarioPicis》这是近期的科学作业。科学知识我们已经学过石头的分类，石头的产生，生物演变，地形变化，地表变化，化石种类，地震以及火山的形成和规律，放射性物质考古，石头绝对年龄（用于岩石），石头的像对年龄（适合沉积石），海底板块运动，考古各种定理。 而这项作业则综合了上述所有知识。题目是：给你的一个时间段，那么自己想象出一种生物，一定是现在不存在的，而且考古历史中没有被发现的。假设你就是发现这个生物的化石的考古学家，写一篇新闻报告，阐述你是如何找到化石，什么样的化石（大概描述），化石的地理位置（这方面要查很多资料），你发现的生物有什么特征（要符合当时的时间段普遍特征），长什么样子，多大，吃什么，被什么吃，何时灭绝的（查大量资料）。 而我的时间段恰好是是古生代的志留纪，很远古，资料少，难度系数更大。查了两周资料左拼又凑才写得新闻报告。我打算发现的生物是：一条叫做primamalariopicis的鱼（名字瞎起的，越接近拉丁文越好），这条鱼是第一个由下颌的鱼，也是早期的肉食动物。 http://zuowen.sanwen.net/-Suntimeseveningnews- PRESSRELEASE AdiscoveryofPrimamalaioPicisinNorthAmerica ——World’sfirstjawedfishappearedinSilurianperiod March,14,2008.JingluSun,aformermemberofLigonmiddleschool,nowapaleontologist,hasrecentlydiscoveredafossilofanunknownfishintheMojaveDesertofLasVegas.Accordingtotheageofthisfossil,thisfishwasdeterminedtobeinSilurianperiod.Thiswastheoldestjawedfisheverfound. Dr.Sunwasgoingintothedesertforatripandlookingfortracesofancientanimalsatthesametimewhenthisfossilcameintoview.ItwasdecidedthatthisnewspeciewillbenamedthePrimamalaioPicis(meaningtheworld’sfirstknownjawedfish).ItisknownastheJawzishtoday. DuringtheSilurianperiod,SupercontinentGondwanacontinuesheadingtowardsSouthPole.Siberia,Laurentia,Balticastayattheequator.Atthistime,theplanetwasingreenhousephase,temperaturewassuitable.DeglaciationcausedriseinsealevelsothatNorthAmericawasstillcoveredinshallowsea,theImpetusOcean,andwasrichinmarine.Brachiopodsandcrinoidswaswidespreadintheocean,molluskandotherjawlessfishwasalsocommon.AndthiscontributestotheexistenceofPrimamalaioPicis,becausewithitsjaws,itcantearfleshofitsprey. Thisfossilagedaround440millionyearsago,duringthePaleozoicera,Silurianperiod.ThiscastfossilwascomposedoflimestonesthatwasdepositedintheMojaveDesertlateron.Fortunately,80%percentofthefossilmaterialwasfound.Thefossilmeasured24.9cmfromitssnouttoitsuppertrunkand13.7cmwide,includingthefish’shead,spine,bones,thefinsandeventheteeth!Butitslowerjawwasmissingandthepartwhereitstailoriginallyshouldbewascompletelyslicedoff.“Becausewecouldtellfromtheupperjawandthetwolongsharpteeththattheremusthavebeenalowerjawandtwomorelowerteethaswell,PrimamalaioPicisisoneoftheworld’searliestcarnivals.”SaysDr.Sun.“Andevenwithoutitstailinthefossil,wecouldstilltellthefishwouldsizearound30cmlong,relativelythesizeofacarp.” PrimamalaioPicishadaratherlarge,bullet-shapedbonyhead,longroundishreptile-likebodyandchubbytail.Despiteitslargebody,ithadverysmalleyesandonlyfoursharpteeth.Therearefinsatbothsidesandupthewherethespineis.Thefishisquitelongsothatitcanbeasflexibletocircleitstail,formingthiswavyline.Sincenoskinwaspreserved,wecouldnotbesurehowitscolorationwas.Butsinceitwasnotatropicalfish,norasmallone,soit’smostlikelytobesilverfish-grayishincolor,perhapswithstripestoo,soitcouldblendintothebackground,makingithardtonotice.Despitethefactthatitwasaprettylargeandstrongfish,andnootherfishwasbigorstrongenoughtoeatit,itstillmustalsohavehadlotsofrowsofscaleinordertoprotectitselffromthenaturalenvironmentsuchashardobjectsandreefs.Overall,PrimamalaioPicishasthestructureofabonefishbutanappearance/figureofashark. Asmentionedearlier,PrimamalaioPicislivedinshallowseaswithavarietyofothermarinewhiletheplanetwasingreenhousephase.Theclimateiswarmandsuitableforallthefishes,sunlightwasplentifulforalgaeandweedplantstogrow,andthisprovidesfoodforsmallphytophagousfishessuchasbirkenia.AndallthosesmallfishesprovidefoodforjawedfishlikePrimamalaioPicis.Ofcourse,itisnottheonlylivingthingduringtheSilurianperiod;otherorganismssuchasbrachiopods,crinoidsandmollusksallsharethishabitat. TherewasamassextinctionattheendofDevonianperiodcausedbyGlaciationsandmeteoriteimpactthatwipedout30%percentoftheanimals.Plantscouldn’tgetenoughsunlight,smallfishesdiedoutandPrimamalaioPiciseventuallydisappearduetolackofprey. “We’renotsurehowthisallends,butPrimamalaioPiciscanactuallybeancestorstomodernshark.”SaysDr.Sun ### Ifyou’dlikemoreinformationaboutthistopic,ortoscheduleaninterviewwithDr.Sun,pleaseemailheratjinglu-sun@hotmail.com 《PrimamalarioPicis》