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Amecephalus jamisoni (Robison & Babcock 2011)
Diagnosis.—Amecephalus with long, prominent medial spines on occipital ring and thoracic segments 4 to 12, and variably present on thoracic segments 1 to 3. Glabella moderately tapered, S1 and S2 well developed, S3 and S4 weak. Anterior branches of facial suture strongly divergent. Genal spines moderately long. Thorax having as many as 17 segments, with falcate pleural tips progressively lengthening rearward on anterior thorax and progressively shortening rearward on posterior thorax. Pygidium micropygous, alate with posterior median notch. Etymology.—After Paul Jamison, who collected and prepared the holotype. He also collected and generously donated other specimens used in this study. Types.—Holotype, UU 10051.60 Discussion.—Amecephalus jamisoni differs from all described species of Amecephalus by the presence of an occipital spine and a medial axial spine on most thoracic segments. Its pygidium is known from an unnamed Spence Shale specimen illustrated on the Internet (Marshall, 2011). Most known specimens of A. jamisoni are preserved with the micropygous pygidium and some segments of the posterior thorax projecting downward into the matrix, or tucked under the dorsal surface (see especially Figs. 15.1–15.2). This manner of preservation is interpreted as taphonomic in origin and related to loose flopping of the pygidium as the specimen was carried in a current prior to burial. Occurrence.—Amecephalus jamisoni is rare in the middle part of the Spence Shale at Wellsville Mountain.
Spence Shale Miaolingian: Wuliuan USAywang21
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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 USAywang21
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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 USAywang21
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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 USAywang21
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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 USAywang21
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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 USAywang21
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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 USAywang21
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Norwoodia boninoi (Robison & Babcock, 2011)
Diagnosis Norwoodia with wide anterior and lateral cephalic border furrow. Glabella short, slightly tapered, diminishing in relative length through ontogeny; lateral furrows weak to effaced. Occipital furrow weak to effaced. Occipital ring, with medial node, merging rearward into long, stout, variably flattened occipital spine. Palpebral lobes about half as long as glabella, opposite anterior glabella. Anterior sections of facial suture weakly divergent, posterior sections diverge laterally and slightly forward to border furrow and then gently curve rearward to lateral cephalic margin. Genal spines long and stout, similar in length to occipital spine, all three approximately reaching an imaginary transverse line near thoracic-pygidial boundary. Cephalic doublure with small anterior rostellum and posterior median suture. Thorax containing nine segments; unusually narrow and subcircular in outline, being slightly more than half as wide as maximum width of cephalon. Fourth thoracic segment having exceptionally long, slender, posteriorly directed, medial spine, its length greater than exoskeleton without spine. Pygidium tiny, short, and alate; width more than three times length; axis with two rings. Etymology After Enrico Bonino, for promoting knowledge of trilobites. Discussion Norwoodia boninoi is a macrocephalic trilobite that has a general morphology reminiscent of, and probably convergent with, some mid-Paleozoic bellinurid xiphosurans.
Weeks Upper Middle Cambrian, Cenomanian Stage USAywang21
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Cedarina schachti n. sp.
Diagnosis Frontal area and preglabellar field long; anterior border evenly anteriorly arcuate; anterior sections of facial suture strongly anteriorly divergent; palpebral lobes large; pygidium relatively narrow and long. Etymology The species is named in honour of Robert Schacht, who collected and donated the holotype and one of the paratype specimens. source: The Marjuman trilobite Cedarina Lochman: thoracic morphology, systematics, and new species from western Utah and eastern Nevada, USA The thorax of C. schachti has ten segments. The segments have a simple morphology (Fig. 5), featuring a well impressed pleural furrow with a transverse course and distal pleural regions that are tapered into blunt, posteriorly directed pleural spines. The eighth segment bears a long median axial spine. None of the other segments bear any axial nodes or spines. This morphology is all but identical to that seen in the articulated "richardsonellines" cited above. The only difference is that the remopleuridids have two additional thoracic segments posterior to the spine-bearing eighth.
Weeks Upper Middle Cambrian, Cenomanian Stage USAywang21
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Duslia insignis Jahn, 1893
Originally described by Jahn (1983) as a chitnoid mollusc. It was recognized as an arthropod by Pilsbry (1900) and Fritsch (1908). It also shows some morphological analogies with Cheloniellon, Pseudoarthron and Triopus. Duslia inhabited a nearshore shallow marine environment and was probably a benthic animal which lived buried in sandy substrate near the sediment-water interface.
Letna Formation 2020 Late Ordovicianywang21