For 270 million years , trilobites were among the dominant species on Earth . Around the world , they will tracks known asCruzianaas they passed . One type of photographic print , known asCruziana rugosa , has long at a loss paleontologists , since the maker of these strange paths could not be identified . Now , however , the secret may have been solved , with the uncovering of a eccentric of trilobite well suited to make the parallel lines realize in theC. rugosa .
Dr Diego Garcia - Bellidoof the University of Adelaide has help describe the new species of trilobite , Megistaspis ( Ekeraspis ) hammondi , inScientific Reports . Three specimen were found in Maroc rock-and-roll dated to 478 million years ago .
Like other trilobites , M. hammondiwas flat with a broad head , taper body , and a lot of legs . outstandingly , however , the three pairs of front legs each had short , stubby spines known as setae . Garcia - Bellido sees the account to theC. rugosain these seta .
Cruziana rugosa ( a ) compare with tracks from know trilobite species . Gutierrez - Marco et al / Scientific Reports
“ Cruzianaare very rough-cut , ” Garcia - Bellido told IFLScience . “ But theCruziana rugosawere not . They were only base for a short period of time around the border of Gondwanaland . ” The timing matches very well with the age of the fogy Garcia - Bellido discover .
Besides resolving theC. rugosamystery , the discovery ofM. hammondiis meaning for the strange preservation of the soft torso portion . The overwhelming majority of know trilobite fogey only show the hard exoskeleton , with the hide and internal organs lose to scavenging or radioactive decay .
The digestive system ofM. hammondisuggests it ate by salvage for decaying consistency and through deposit eating , eat up the clay at the bottom of the sea and pull up the food using powerful enzymes in its venter , Garcia - Bellido bestow . The job of the front legs was to shovel the sediment into the creature ’s mouthpiece . In the process , they leave 12 parallel rut in the mud , which in some cases became preserved to be found by us almost 500 million years later .
Most trilobite process were too diffuse to survive such treatment , Garcia - Bellido told IFLScience , but the spines were short and thick enough to plow the mud unharmed .
M. hammondiwas also typical in commingle digestive features that have been seen in unlike trilobites , but never together . Specifically , a “ crop ” in which food is stored near the mouth has previously been fancy as an option to multiple digestive secreter have sex as caecum , butM. hammondihad both . The evolutionary rationality for this remains unknown .
( a ) Overall view of one of the specimens . Yellow arrow channelise to setae think to have carve the Cruziana rugosa ; black arrows point thoracic endopods ; green arrow point to left oculus ; low arrowhead indicate the facial suture ; ( b ) and ( c ) Detail of the seta . Scale cake , 20?mm for ( a ) ; 10?mm for ( b , speed of light ) . Gutierrez - Marco et al / Scientific Reports
