Kingaspidoides spinirecurvatus: A new species of Trilobite from the Cambrian of the Anti‑Atlas, Morocco, with unexpectedly curved spines.
[sciencythoughts.blogspot.com]
The development of spines in Trilobites reflects an evolutionary arms race over most of the Palaeozoic. This is particularly signposted by a palpable bloom of spiny Trilobites from the late Silurian to the end of the Devonian. Spines are present among the earliest Trilobites at the base of Cambrian Stage 3, but these include genal spines and more or less pronounced pleural spines only (as in genera such as Eofallotaspis, Fallotaspis or Archaeaspis). All of these are best regarded as representing part of a beneficial cover by the dorsal exoskeleton in species that needed to perform a more or less distinct inclination of the body along the length axis to allow pronounced enrolment, in some species possibly combined with improved stability on a soft substrate. Early Cambrian Trilobites generally retained such a 'primordial' organisation and spinosity. However, small to medium-sized spines on the occipital ring, axial rings or the lateral and posterior margins of the pygidium developed progressively, apparently as a response to environmental factors, and all of them were nearly upright to more or less gently rearwardly directed. It is generally accepted that new selective pressures from predators prompted animals to craft innovative protective devices, which in several species included longer and more strongly curved spines.
6
Enjoy being online again!
Welcome to the community of good people who base their values on evidence and appreciate civil discourse - the social network you will enjoy.Create your free account
Recent Visitors 16
Photos 292 More
Posted by JoeBKite-like structures in the western Sahara Desert.
Posted by TriphidAn Aussie Indigenous Message Stick.
Posted by TriphidIndigenous Australian Aboriginal Rock art dated somewhere between 20 and 30 thousand years old.
Posted by TriphidIndigenous Australian Aboriginal Rock art dated somewhere between 20 and 30 thousand years old.
Posted by TriphidIndigenous Australian Aboriginal Rock art dated somewhere between 20 and 30 thousand years old.
Posted by TriphidIndigenous Australian Aboriginal Rock art dated somewhere between 20 and 30 thousand years old.
Posted by JoeBDortoka vremiri: A new species of Dortokid Turtle from the Late Cretaceous of the Hațeg Basin, Romania.
Posted by JoeBThe Cabeço da Amoreira burial: An Early Modern Era West African buried in a Mesolithic shell midden in Portugal.
Posted by JoeBMusivavis amabilis: A new species of Enantiornithine Bird from the Early Cretaceous Jehol Biota of northeastern China.
Posted by JoeBTorosaurus in Canada.
Posted by JoeBStone tools from the Borselan Rock Shelter, in the Binalud Mountains of northeastern Iran.
Posted by JoeBDating the Lantian Biota.
Posted by JoeBBashanosaurus primitivus: A new species of Stegosaur from the Middle Jurassic of Chongqing Municipality, China.
Posted by JoeBDetermining the time of year when the Chicxulub Impactor fell.
Posted by JoeBSão Tomé and Príncipe: Possibly the last country on Earth never to have been visited by a working archaeologist.
Posted by JoeBMambawakale ruhuhu: A new species of Pseudosuchian Archosaur from the Middle Triassic Manda Beds of Tanzania.