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Sphaerocoryphe arachniformis

Artiopoda - Phacopida - Cheiruridae

Sister species lacking formal opinion data

Synonymy list
YearName and author
1930Sphaerocoryphe arachniformis Bradley pp. 284 - 285 figs. pl. 30 f. 1-2
1997Sphaerocoryphe arachniformis Tripp et al. pp. 776, Table 2

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Protostomia
EcdysozoaAguinaldo et al. 1997
Panarthropoda
phylumArthropodaGravenhorst 1843
classArtiopodaHou and Bergstrom
RankNameAuthor
classTrilobitaWalch 1771
orderPhacopidaSalter 1864
suborderCheirurinaHarrington and Leanza 1957
familyCheiruridaeHawle and Corda 1847
subfamilyDeiphoninaeRaymond 1913
genusSphaerocorypheAngelin 1854
speciesarachniformis

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.

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Diagnosis
ReferenceDiagnosis
J. H. Bradley 1930Cephalon semielliptical in outline, moderately convex, genal angles produced into rather long, flattened spines, which curve well backward. Dorsal furrows deep except opposite the lateral glabellar furrows, where they become shallow; subparallel until just before reaching the anterior marginal furrow, where they begin to diverge slightly. Wide, shallow, marginal furrows separate the fixed cheeks from the border which is very narrow, thin, and slightly in flexed anterior to the glabella, but wider and thicker on the lateral margins; posteriorly the border is narrow at the dorsal furrows but widens gradually to the genal angles.

The glabella is very prominent, anterior lobe inflated to form an oblate spheroid with its transverse diameter the longest, comprising about three-fourths the entire length. The anterior lobe is encircled by a pair of wide, shallow furrows whose anterior margin is defined by an angular ridge. Laterally these furrows join the dorsal furrows. Near the junction of the occipital and dorsal furrows are situated a pair of triangular lobes which are formed by the widening and deepening of the posterior glabellar furrows until they join the occipital furrow. Occipital segment arched well forward, its posterior margin elevated, surface sloping abruptly into the occipital furrow, which is shallow, not defined anteriorly except behind the posterior glabellar lobes.

The fixed cheeks are large for the genus, convex, sloping abruptly to the dorsal furrows, more gently to the posterior and lateral margins. The facial sutures originate well forward on the lateral margins, extending inward and slightly backward in a sigmoid curve to the base of the palpebral lobes which they traverse, and thence forward to the anterior margin just outside of the dorsal furrows. The free cheeks are triangular, less than onequarter the size of the fixed cheeks. Eyes prominent, globular, pointed forward, situated opposite the anterior border of the posterior glabellar lobes. Indistinct ocular ridges extend from near the anterior margin of the glabella to the eyes.

The surface of the glabella is smooth except for a few scattered tubercles on the posterior portion of the anterior lobe j the cheeks are finely and closely pitted within the marginal furrows, and smooth on the borders.