-
Perspicaris dilatus (Robison & Richards, 1981)
Perspicaris is a fossil arthropod from the Cambrian period. It was 2–3 centimetres (0.8–1.2 in) long and bivalved. The valves, encasing the thorax, were joined together by a dorsal hinge. It is difficult to establish the lifestyle of Perspicaris. Its large eyes and other parts would suggest a swimming animal, yet it lacks claws, which seems to suggest a bottom feeder. Two species of Perspicaris are found in the famous Burgess Shale in British Columbia, Canada. 202 specimens of Perspicaris are known from the Greater Phyllopod bed, where they comprise 0.38% of the community. Perspicaris has been identified as an arthropod that is a member of a clade close to the crown-group of Euarthropoda, which includes myriapods, chelicerates, insects and crustaceans.
Wheeler Shale Miaolingian USA
ywang21
-
Gogia spiralis (Robison, 1965)
Gogia is a Cambrian cystoid that is among the earliest and most primitive groups of echinoderms. For this reason they are sometimes called a "dawn crinoids". They had a vase-shaped body (calyx), covered by plates that were symmetrical and have a bifurcated brachiole, a slender arm-like structure for food-gathering that closely resembled those in cystoids. Gogia differed from true crinoids in that they had pores along the margins separating the plates, and the type of feeding arms they displayed. The species Gogia spiralis derives its name from its tightly spiraled arms and is only one of three Gogia species to have spiraled arms. Gogia had a vase-shaped body or calyx with irregularly positioned plates. It also had a stalk made up of smaller plates that attached to the sea floor, and food-gathering arm-like structures called brachioles. Gogia was a sessile (stationary) suspension feeder gathering food with its arms in calm waters of shallow Cambrian seas. Gogia spiralis usually attached directly to the mud, but on rare occasions attached to brachiopods and trilobite fragments on the sea floor. Gogia were widely distributed in the lower and middle Cambrian of western North America, but only a few partial specimens have been found in the Burgess Shale. Gogia occurred at the base of the cystoid radiation, with three distinct cystoid lineages derived from different Gogia species. Gogia lived only during the Cambrian time period, but the cystoids that evolved from them survived until the end of the Devonian.
Wheeler Shale Miaolingian USA
ywang21
-
Olenoides vali (Robison & Babcock, 2011)
Diagnosis.—Olenoides with weak anterior expansion of glabella. Posterior cephalic border having tiny intergenal spines, with posterior cephalic margins between intergenal and genal spines deflected forward. Genal spines long, terminating approximately opposite front of pygidium. Occipital spine exceptionally long, arching strongly upward and rearward, terminating just in front of thoracic-pygidial boundary. Medial thoracic spines projecting upward with minor rear curvature and with length progressively increasing rearward from short to quite long beneath arching occipital spine; medial spine on eighth thoracic segment approximately same length as pygidial axis. Paired marginal spines on thorax and pygidium progressively increase in length rearward, with length of posterior pygidial pair similar to that of genal spines. Pygidium having three pairs of marginal spines and axis with four rings and terminal piece. Etymology.—After Val G. Gunther, for his many contributions to knowledge of Cambrian fossils (e.g., Gunther and Gunther, 1981). Holotype.—Exoskeleton, UU 10051.18 Discussion.—Olenoides vali n. sp. and O. trispinosus Rasetti (1946) are the only species of Olenoides known to have three pairs of marginal spines on the pygidium. However, the pygidial spines of O. vali markedly increase in length toward the rear, whereas those of O. trispinosus decrease in length toward the rear. Also, the pygidial axis of O. vali has four rings and a terminal piece, whereas O. trispinosus has five rings and a terminal piece. Olenoides vali further differs from all other species of Olenoides by exceptional elongation of the occipital spine and greater rearward elongation of medial spines on the thorax. White (1973), in an unpublished thesis, described a poorly preserved exoskeleton and a few small, disarticulated sclerites, here assigned to Olenoides trispinosus. Comparison of specimens known to the present authors shows a minor ontogenetic increase in lateral expansion of the anterior glabella. In some specimens, that expansion was further increased by taphonomic compression. Olenoides rooksi Bonino and Kier (2009) is an unavailable name because it fails to meet criteria of Article 13 of the International Code of Zoological Nomenclature. Occurrence.—Olenoides vali has an observed stratigraphic range through approximately the upper 110 m of the Wheeler Formation in the Drum Mountains, as defined herein. Some collectors have referred specimens from the upper part of this interval to either the Marjum or Pierson Cove formations.
Wheeler Shale Miaolingian USA
ywang21
-
Olenoides nevadensis (Meek, 1870)
Olenoides is an average size trilobite (up to 9 cm long), broadly oval in outline. Its cephalon is semi-circular. The glabella is parallel-sided, rounded at its front and almost reaches the anterior border. Narrow occular ridges curve backwards from the front of the glabella to the small, outwardly-bowed eyes. The librigenae narrow backward into straight, slender genal spines that reach as far as the third thorax segment. Thorax consists of seven segments that end in needle-like spines. pygidium) has six axial rings that decrease in size backwards and four or five pairs of rearward pointing marginal spines. Cephalon, thorax and pygidium are of approximately equal length.
Wheeler Shale Miaolingian USA
ywang21
-
Emeraldella brocki (Walcott, 1912)
Emeraldella is a genus of arthropod known from the Middle Cambrian of North America. The type species E. brocki was described in 1912 from the Burgess Shale.21 specimens of Emeraldella are known from the Greater Phyllopod bed, where they comprise < 0.1% of the community.[2] A re-study on the species was done in 2012.A second species E. brutoni is known from the Wheeler Shale, which was described in 2011.An additional specimen of E. brutoni was described in 2019, which revealed more of the anatomy.
Wheeler Shale Miaolingian USA
ywang21
-
Naraoia cf. compacta
Naraoia is almost flat (dorso-ventrally). The upper (or dorsal) side of the body consists of a non-calcified transversely oval or semi-circular headshield (cephalon), and a tailshield (pygidium) longer than the cephalon, without any body segments in between. The body is narrowed at the articulation between cephalon and pygidium. The long many-segmented antennas are directed sideways. There are no eyes. The gut has a relatively large diameter (14-18% of the width of the body), and next to four pairs of large digestive sacs (or caeca). The cephalon has branched diverticula occupying most of the cephalon (unlike in Misszhouia). Naraoia had appendages with two branches on a common basis, like Misszhouia and trilobites. At least the anterior trunk limbs have exopods with large, paddle-shaped distal lobes and short flattened side branches (setae) on the shaft. The endopod (known only in N. compacta) is composed of six podomeres.
Wheeler Shale Miaolingian USA
ywang21
-
Kootenia randolphi (Robison & Babcock, 2011)
Diagnosis.—Kootenia having ovate exoskeletal outline. Glabella slightly expanding forward, indenting narrow anterior cranidial border. Occipital ring with short median spine. Genal spines short to moderately long, with tips opposite thoracic axial ring 2 to 4. Thoracic axial rings each having median spine slightly shorter than that of occipital ring. Paired pleural spines of thorax and pygidium gradually increase in length rearward. Pygidial axis containing four rings and terminal piece, border having four pairs of marginal spines. Spaces between pygidial spines progressively widen rearward. Etymology.—After Robert L. Randolph, for initial study of trilobites from the Swasey Formation in the Drum Mountains (Randolph, 1973). Holotype.—Exoskeleton, BPM 1004 Discussion.—Kootenia randolphi resembles K. youngorum n. sp. but differs by having 4 rather than 5 pairs of marginal spines on the pygidium. Also, the spacing and patterns of spine elongation differ. Kootenia randolphi is the only species of Kootenia known to have four pairs of marginal spines on the pygidium so far described from the Wheeler Formation or its lateral equivalents in the Great Basin. Occurrence.—Locally common in the upper 30 m of the Wheeler Formation of the Drum Mountains, as used here, where it occurs in the lower Bolaspidella Zone. Some authors have referred these strata to the Pierson Cove Formation.
Wheeler Shale Miaolingian USA
ywang21
-
Elrathia kingi (Meek, 1870)
Elrathia is a genus of ptychopariid trilobite species that lived during the Middle Cambrian of Utah, and possibly British Columbia. E. kingii is one of the most common trilobite fossils in the USA locally found in extremely high concentrations within the Wheeler Formation in the U.S. state of Utah. E. kingii has been considered the most recognizable trilobite. Commercial quarries extract E. kingii in prolific numbers, with just one commercial collector estimating 1.5 million specimens extracted in a 20-year career. 1950 specimens of Elrathia are known from the Greater Phyllopod bed, where they comprise 3.7% of the community. Etymology - Even though the generic name Elrathia was first published in the combination E. kingii, a species from the House Range, Utah, the name, itself, is derived from Elrath, Cherokee County, Alabama. Description - E. kingii is a medium-sized trilobite with a smooth sub-ovate carapace that is tapered towards the rear. Thorax is usually 13 segments. Pygidium has four axial rings and a long terminal piece. Posterior margin of the pygidium has a long broad medial notch. In contrast, E. marjum usually has 12 segments, 5 axial rings, lacks a notched posterior margin and possess incipient antero-lateral spines. The British Columbian species, E. permulta, is much smaller, averaging about only 20 millimeters, and has up to thoracic 14 segments. Because E. permulta lacks several diagnostic features of the genus it may even represent a distinct genus. Synonyms - Elrathia is variously known as Elrathina, which is a separate genus sometimes considered to be a synonym of Ptychoparella. The species E. kingii is often erroneously called E. kingi (with one i).
Wheeler Shale Miaolingian USA
ywang21
-
Asaphiscus wheeleri (Meek, 1873)
Distribution - A. wheeleri occurs in the Middle Cambrian of the United States (Delamaran, Lower Wheeler Shale, Millard County, Utah, 40.0°N, 113.0°W; and Menevian, Wheeler Formation, House Range, Utah, 39.2° N, 113.3° W). Description - Asaphiscus are average size trilobites of (up to 8 centimetres or 3.1 inches) with a rather flat calcified dorsal exoskeleton of inverted egg-shaped outline, about 1½× longer than wide, with the widest point near the back of the headshield (or cephalon). The cephalon is about 40% of the body length, is semi-circular in shape, has wide rounded genal angles, and a well defined border of about ⅛× the length of the cephalon. The central raised area of the cephalon (or glabella is conical in outline with a wide rounded front and is separated from the border by a preglabellar field of about ⅛× the length of the cephalon, and has 3 sets of furrows that may be clear or inconspicuous. The articulated middle part of the body (or thorax) has 7-11 segments (9 in A. wheeleri), with rounded tips. The tailshield (or pygidium) is about 30% of the body length, is semi-circular in shape, with a wide flat border, and an entire margin. A Chinese trilobite Tenistion typicalis was used for scale.
Wheeler Shale Miaolingian USA
ywang21
