Wanneria

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Wanneria
Temporal range: late Lower Cambrian (middle Upper Olenellus-zone)
524–518.5  Ma
Wanneria walcottana negative CRF.jpg
A Wanneria walcottana negative imprint, from the Kinzers Shale
Scientific classification
Kingdom:
Animalia
Phylum:
Arthropoda
Class:
Trilobita
Order:
Redlichiida
Suborder:
Olenellina
Superfamily:
Olenelloidea
Family:
“Wanneriidae”
Subfamily:
“Wanneriinae”
Genus:
†Wanneria

Walcott, 1910
Binomial name
†Wanneria walcottana
(Wanner, 1901)
Other species
  • †W. cranbrookenseWebster in Webster & Caron, 2024 [1]
Synonyms
  • Olenellus (Holmia) walcottanus [2]

Wanneria is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the later part of the Botomian stage, [3] which lasted from approximately 524 to 518.5 million years ago. This faunal stage was part of the Cambrian Period. [3] W. walcottana and W. cranbrookense are the only known species in this genus. [1]

Contents

Description

As with most early trilobites, Wanneria walcottana has an almost flat exoskeleton, that is only thinly calcified, and has crescent-shaped eye ridges. As part of the Olenellina suborder, Wanneria lacks dorsal sutures. Like all other members of the Olenelloidea superfamily, the eye-ridges spring from the back of the frontal lobe (L4) of the central area of the cephalon, that is called glabella. The dorsal exoskeleton of Wanneria has an inverted egg shaped outline, approximately 1½ times longer than wide, ignoring the pleural spines, and is at its widest at the back of the cephalon. The horizontal outline of the head (or cephalon) is semi-circular with the back (or posterior margin) perpendicular to the midline or somewhat arching backwards. The L4 is wider than the other lobes, and touches the raised ridge (or anterior border) at the front of the cephalon. The right and left furrow (S1) between the first (L1) and second (L2) pair of side lobes (counted from the back of the cephalon) do not join across the midline, and angle forwards from the middle to the side. The sickle shaped eyes are attached to the back of L4 and extend backwards to the most backward set of side-lobes of the glabella (or L1). The rim of the cephalon is extended into backward pointing genal spines, that reach back to approximately the 4th thorax segment. Its body (or thorax) has 17 segments, with nodes on thorax segments 1 to 14, and a short spine on segment 15 that is at its base about ¼ as wide as the axis. The axis is about ¼ as wide as the thorax. Unlike in the majority of the Olenelloidea, in Wanneria thorax segment 3 is not macro-pleural, but equal in size and shape to neighboring segments. Pleural spines slightly arched backwards, extending sideward in the most frontal thorax segments, but gradually more backward and eventually even arching slightly inward in segment 17. [4]

Distribution

Wanneria walcottana occurs in the middle Upper Olenellus-zone of Pennsylvania (Kinzers Formation, road metal quarry and walls of demolished tenant house on Noah L. Getz farm, on Harrisburg Pike, 1 mile (1.6 km) north of Rohrerstown, about 2.5 miles (4 km) west of Lancaster, Lancaster County, 40°0′N76°42′W / 40.000°N 76.700°W / 40.000; -76.700 ), [5] [4] of Nevada (Harkless Formation, North-East of Goldpoint, Dyeran, Esmeralda County, 37°24′N117°24′W / 37.400°N 117.400°W / 37.400; -117.400 ), [6] Mexico (Buelna Formation, Cerro Rajon, Caborca Region, 30°24′N111°54′W / 30.400°N 111.900°W / 30.400; -111.900 ) [7] and of Greenland. [4]

Wanneria cranbrookense only occurs in the Eager Formation of British Colombia, Canada. [1]

Taxonomy

Relationship within the Olenellidae

Wanneria is close to the common ancestor of the Holmiidae, and of the clade comprising Fritzolenellus , Mummaspis , Laudonia , the Biceratopsinae and the Bristoliinae. So far, cladistic analysis could not determine which two of these groups are closer. This large group together is the sister group to Elliptocephala . [8]

Species previously assigned to Wanneria

Related Research Articles

<span class="mw-page-title-main">Redlichiida</span> Extinct order of trilobites

Redlichiida is an order of trilobites, a group of extinct marine arthropods. Species assigned to the order Redlichiida are among the first trilobites to appear in the fossil record, about halfway during the Lower Cambrian. Due to the difficulty to relate sediments in different areas, there remains some discussion, but among the earliest are Fallotaspis, and Lemdadella, both belonging to this order. The first representatives of the orders Corynexochida and Ptychopariida also appear very early on and may prove to be even earlier than any redlichiid species. In terms of anatomical comparison, the earliest redlichiid species are probably ancestral to all other trilobite orders and share many primitive characters. The last redlichiid trilobites died out before the end of the Middle Cambrian.

<i>Olenellus</i> Extinct genus of trilobites

Olenellus is an extinct genus of redlichiid trilobites, with species of average size. It lived during the Botomian and Toyonian stages (Olenellus-zone), 522 to 510 million years ago, in what is currently North-America, part of the palaeocontinent Laurentia.

<i>Paradoxides</i> Extinct genus of trilobites

Paradoxides is a genus of large to very large trilobite found throughout the world during the Middle Cambrian period. One record-breaking specimen of Paradoxides davidis, described by John William Salter in 1863, is 37 cm (15 in). The cephalon was semicircular with free cheeks ending in long, narrow, recurved spines. Eyes were crescent shaped providing an almost 360° view, but only in the horizontal plane. Its elongate thorax was composed of 19–21 segments and adorned with longish, recurved pleural spines. Its pygidium was comparatively small. Paradoxides is a characteristic Middle-Cambrian trilobite of the 'Atlantic' (Avalonian) fauna. Avalonian rocks were deposited near a small continent called Avalonia in the Paleozoic Iapetus Ocean. Avalonian beds are now in a narrow strip along the East Coast of North America, and in Europe.

<span class="mw-page-title-main">Olenellina</span> Extinct suborder of trilobites

Olenellina is a suborder of the order Redlichiida of trilobites that occurs about halfway during the Lower Cambrian, at the start of the stage called the Atdabanian. Olenellina are arguably the earliest trilobites in the fossil record as members of Redlichiina, although Ptychopariida and Eodiscina follow soon after. The suborder died out when the Lower Cambrian passed into the Middle Cambrian, at the end of the stage called Toyonian. A feature uniting the Olenellina is the lack of rupture lines in the headshield, which in other trilobites assist the periodic moulting, associated with arthropod growth. Some derived trilobites have lost facial sutures again, but all of these are blind, while all Olenellina have eyes.

<i>Analox</i> Extinct genus of trilobites

Analox Rasetti, 1966 is a genus of Eodiscinid trilobites belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida It lived during the Botomian stage. It can easily be distinguished from other trilobites by the two furrows that extend forwards and sidewards from the front of the glabella.

<i>Olenelloides</i>

Olenelloides armatus is an extinct, small sized olenelloid redlichiid trilobite arthropod. It lived during the later part of the Botomian stage, which lasted from approximately 524 to 518.5 million years ago. This faunal stage was part of the Cambrian Period. The most conspicuous feature is the hexagonal head shield that carries 6 ray-like spines..

Elliptocephala is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived from the later part of the Tommotian to the upper Botomian. Elliptocephala can easily be confused with Ellipsocephalus, a trilobite genus of the Ptychopariida order.

<i>Nephrolenellus</i>

Nephrolenellus is an extinct genus of trilobite, fossil marine arthropods, of relatively small size. Currently two species are attributed to it. Nephrolenellus lived at the end of the Lower Cambrian. Species are known from the Great Basin of California, Nevada and Arizona, with one specimen from Canada.

<i>Mesonacis</i>

Mesonacis is an extinct genus of trilobite that lived during the Botomian, found in North-America, and the United Kingdom. Some of the species now regarded part of Mesonacis, have previously been assigned to Angustolenellus or Olenellus (Angustolenellus). Angustolenellus is now regarded a junior synonym of Mesonacis.

<i>Fallotaspis</i> Cambrian Period genus of trilobites

Fallotaspis is a genus of redlichiid trilobites found in Early Cambrian-aged strata of the United States and Morocco.

<span class="mw-page-title-main">Holmiidae</span> Family of trilobites

Holmiidae is a family of trilobites, that lived during the Lower Cambrian (Atdabanian). The Holmiidae is a diverse family of eight genera containing at least 17 species. It includes some of the earliest trilobites of Baltica. Holmiidae occur throughout Baltica and Western Laurentia, and also in Morocco.

<i>Biceratops</i>

Biceratops is an extinct genus of olenelloid redlichiid trilobites, of average size, with the largest specimen 8 centimetres or 3.1 inches long, not including the huge pleural spines of the 3rd segment of the thorax. It lived during the Toyonian stage, in what is today the South-Western United States. Biceratops can easily be distinguished from other members of Biceratopsidae by the absence of genal spines, in combination with effaced features of the raised axial area of the head shield, that is bordering the two horn-like projections that carry the eyes. Biceratops nevadensis is the only known species in this genus.

<span class="mw-page-title-main">Olenelloidea</span> Extinct superfamily of trilobites

The Olenelloidea are a superfamily of trilobites, a group of extinct marine arthropods. They lived during the late Lower Cambrian and species occurred on all paleocontinents.

Mesolenellus is an extinct genus of trilobites that lived during the lower Cambrian (Botomian), found in Greenland and Spitsbergen.

Lochmanolenellus is an extinct genus of trilobites, fossil marine arthropods, with one small species, L. mexicana. It lived during the Botomian stage (Olenellus-zone), 522–513 million years ago, in the South-West of the former continent of Laurentia, in what are today Mexico, and the South-Western United States.

<i>Bristolia</i>

Bristolia is an extinct genus of trilobite, fossil marine arthropods, with eight or more small to average size species. It is common in and limited to the Lower Cambrian shelf deposits across the southwestern US, which constitutes part of the former paleocontinent of Laurentia.

<i>Emigrantia</i>

Emigrantia is an extinct genus of trilobites, fossil marine arthropods, of small to average size. It lived during the Toyonian stage, in what is today the South-Western United States. Emigrantia can easily be distinguished from other trilobites by the sturdy but not inflated genal spines, that are attached at midlength of the cephalon, in combination with effaced features of the raised axial area of the head shield.

Bolbolenellus is an extinct genus of trilobites, fossil marine arthropods, with five species attributed to it currently. It can be easily distinguished from all other trilobites by the combination of the absence of dorsal sutures in the head shield like all Olenellina, and a distinctly bulbous frontal lobe (L4) of the raised axial area in the head called glabella. The species lived at the end of the Lower Cambrian.

<i>Orygmaspis</i> Genus of trilobites

Orygmaspis is a genus of asaphid trilobite with an inverted egg-shaped outline, a wide headshield, small eyes, long genal spines, 12 spined thorax segments and a small, short tailshield, with four pairs of spines. It lived during the Late Cambrian in what are today Canada and the United States.

<i>Tricrepicephalus</i>

Tricrepicephalus is an extinct genus of ptychopariid trilobites of the family Tricrepicephalidae with species of average size. Its species lived from 501 to 497 million years ago during the Dresbachian faunal stage of the late Cambrian Period. Fossils of Tricrepicephalus are widespread in Late Cambrian deposits in North America, but is also known from one location in South America. Tricrepicephalus has an inverted egg-shaped exoskeleton, with three characteristic pits in the fold that parallels the margin of the headshield just in front of the central raised area. The articulating middle part of the body has 12 segments and the tailshield carries two long, tubular, curved pygidial spines that are reminiscent of earwig's pincers that rise backwards from the plain of the body at approximately 30°.

References

  1. 1 2 3 Webster, M.; Caron, J.-B. (2024). "Trilobites of the Cranbrook Lagerstätte (Eager Formation, Cambrian Stage 4), British Columbia". Journal of Paleontology: 1–44. doi: 10.1017/jpa.2023.89 .
  2. 1 2 Lieberman, B.S. (1999). "Systematic Revision of the Olenelloidea (Trilobita, Cambrian)" (PDF). Bulletin of the Peabody Museum of Natural History. 45.
  3. 1 2 Sepkoski, Jack (2002). "A compendium of fossil marine animal genera (Trilobita entry)". Bulletins of American Paleontology. 364: 560. Retrieved 2008-01-12.
  4. 1 2 3 Palmer, A.R.; Repina, L.N. (1993), "Through a Glass Darkly: Taxonomy, Phylogeny and Biostratigraphy of the Olenellina", The University of Kansas Paleontological Contributions, 3: 1–35
  5. ↑ Stose, A.J.; Stose, G.W. (1944). "Geology of the Hanover-York District Pennsylvania". Professional Papers (US Geological Survey). 204: 1–84.
  6. ↑ Skovsted, C.B.; Holmer, L.E. (2006). "The Lower Cambrian brachiopod Kyrshabaktella and associated shelly fossils from the Harkless Formation, southern Nevada". Geologiska Föreningen i Stockholm Förhandlingar. 128 (4): 327–337. Bibcode:2006GFF...128..327S. doi:10.1080/11035890601284327. S2CID   129292701.
  7. ↑ Stewart, J.; McMenamin, M.A.S.; Morales-Ramirez, J.M. (1984). "Upper Proterozoic and Cambrian rocks in the Caborca Region, Sonora, Mexico - physical stratigraphy, biostratigraphy, paleocurrent studies, and regional relations". U.S. Geological Survey Professional Papers. 1309: 1–33.
  8. ↑ Lieberman, B.S. (1998). "Cladistic Analysis of the Early Cambrian Olenelloid Trilobites" (PDF). Journal of Paleontology. 72 (1): 59–78. Bibcode:1998JPal...72...59L. doi:10.1017/S0022336000024021. S2CID   86307339.
  9. 1 2 Neltner, L.; Poctey, N. (1950). "Quelques faunes géorgiennes du Maroc". Notes et Mémoires du Service géologique du Maroc. 2 (74): 53–83.
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