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Eumorphocystis multiporata
Taxonomy
Eumorphocystis multiporata was named by Branson and Peck (1940). Its type specimen is 6757 University of Missouri and is a 3D body fossil. Its type locality is Upper Cystoid Zone, Fittstown Roadcut on Oklahoma State Highway 90, which is in a Blackriveran marine sandstone/shale in the Bromide Formation of Oklahoma.
Synonyms
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Synonymy list
| Year | Name and author |
|---|---|
| 1940 | Eumorphocystis multiporata Branson and Peck p. 88–92 figs. pl. 13 |
| 1950 | Regnellicystis typicalis Bassler p. 276–277 figs. pl. 275, figs 6–8 |
| 1950 | Strimplecystis oklahomensis Bassler p. 277 figs. pl. 265, fig. 19. |
| 2018 | Eumorphocystis multiporata Sheffield and Sumrall figs. 3, 5A, 6 |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
†Eumorphocystis multiporata Branson and Peck 1940
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Invalid names: Eumorphocystis oklahomensis Bassler 1950 [synonym], Eumorphocystis typicalis Bassler 1950 [synonym]
Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| S. L. Sheffield and C. D. Sumrall 2018 | Theca, approximately 16 mm in height and 13 mm at the widest point, slightly globular to elongate oval shape with large number of irregularly arranged, polygonal plates (Fig. 6A, B); ambulacra arranged in 2‐1‐2 symmetry and oral plates each bear a high spine and border the peristomial opening; CD interray contains O1, with no evidence of O6 or O7; oral plates are non‐diplopore bearing (Fig. 6C). Primary peristomial cover plates are undifferentiated from the cover plate series; presence of either hydropore or gonopore is not discernable. Periproct located in CD interray, 0.25 mm in diameter, in contact with oral plate in the CD interray; appears to be composed of numerous small plates but disarticulation prevents further detailed descriptions. Ambulacra divided into proximal recumbent portion and distal erect portion. Proximally, ambulacral floor plates are highly differentiated from cover plate series, wedge shaped, singly biserial and alternate with primary food groove along periradial suture; periradial suture follows a zigzag pattern across the theca. Floor plates non‐diplopore bearing; brachioles are mounted in the centre of each ambulacral food plate. Proximal food groove is covered by doubly biserial ambulacral cover plates; distal food groove is formed into erect, triserially‐arranged arms (Fig. 6C).
Portion of arms are exothecally derived from a uniserial extension of the extraxial skeleton; entire arm is supported by a single non‐diplopore bearing thecal plate at the base of the arm connecting with the uniserial extraxial plates (Fig. 6A). Uniserial plates are overlain by singly biserial ambulacral floor plates. The union of biserial ambulacral floor plates and uniserial exothecally‐derived plates is pierced by lumen that runs throughout the appendage and pierces the theca. Brachiole plates articulate directly to short, equant ambulacral floor plates; brachioles extend from the main food groove and attach to the centre of a single floor plate via a short, narrow groove. Uniserial brachioles alternate from left and right along main food groove; first brachiole extending from each ambulacrum is on the left side. Total length of distal ambulacra unknown (Fig. 6C). Thecal plates irregularly shaped, typically five or six‐sided with roughly equal suture lengths, though the plates vary widely with respect to size. The largest thecal plates, presumably primary generation of plates, are typically between 1.0 and 1.5 mm in diameter, whereas presumably secondary generation plates are typically between 0.25 and 0.5 mm in diameter; smaller plates typically roughly quadrangular. The surfaces of the plates are not marked with pits or granulose textures and without evident growth lines; new plates are irregularly added anywhere within the thecal plating. Ridges running horizontally, vertically and diagonally radiate from each arm (three from each arm) across the theca (Fig. 6A). Ridges run from plate centre to plate edge and are much higher towards centre of the plate than at the edge. The thecal plates are noticeably convex and are arched towards the centre of the plate; the sutures between the plates are clearly defined and deeply depressed in all places not altered by taphonomic overprint. Diplopores are simple paired perpendicular canals within very shallow elliptical peripores; average distance between the perpendicular canals is 0.5 mm; average diameter of the pores is 0.2 mm. Each pair of perpendicular canals enters the coelom separately. The diplopores are irregularly clustered, generally within the plate centre; some diplopores cross plate sutures, most commonly in conjunction with smaller plates. Thecal plates with raised ridges typically have fewer or no diplopores present. Basals 4, large, equal‐sized, non‐diplopore bearing; average basal height is 1.5 mm, average width is 3 mm. Basals have thickened ridge around base of attachment structure (Fig. 6B). Only proximal portion of stem is known, preserved length 4.2 mm, circular in cross section with proportionally small circular lumen piercing the centre (approximately 0.2 mm in diameter). No crenulae present. Holomeric stem comprises two distinct alternating columnal sizes, one that is approximately twice as tall as the other (Fig. 6A). |
Measurements
No measurements are available
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| Source: subp = subphylum, p = phylum | |||||
| References: Aberhan 1992, Bambach et al. 2007 | |||||
Age range: Blackriveran or 457.30000 to 449.60000 Ma
Collections (4 total)
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Caradoc | USA (Virginia) | Regnellicystis typicalis (37904) | |
| Blackriveran | USA (Oklahoma) | Eumorphocystis multiporata, Strimplecystis oklahomensis (23990 type locality: 196808) Strimplecystis oklahomensis (37986) |