Asaphida

Dionidella (Huangnigangia) subquadrata

Order Asaphida / Superfamily Trinucleoidea / Family Dionididae

Katian (Late Ordovician)Zhejiang, Jiangsu

Dionidella (Huangnigangia) subquadrata — photo 1 — Photo 1 · Dionide, a trilobite genus name; -ella, a diminutive suffix. Huangnigang, Huangnigang, Jiangshan, Zhejiang. Holotype (Zhejiang; Qiu Hongan et al. 1983) Cephalon and pygidium specimen Cephalon and pygidium specimen (Jiangsu; (Zhejiang; Qiu Hongan et al. 1983) Tripp et al., 1989)

Dionidella (Huangnigangia) subquadrata — photo 2 — Photo 2 · Dionide, a trilobite genus name; -ella, a diminutive suffix. Huangnigang, Huangnigang, Jiangshan, Zhejiang. Holotype (Zhejiang; Qiu Hongan et al. 1983) Cephalon and pygidium specimen Cephalon and pygidium specimen (Jiangsu; (Zhejiang; Qiu Hongan et al. 1983) Tripp et al., 1989)

Dionidella (Huangnigangia) subquadrata — photo 3 — Photo 3 · Dionide, a trilobite genus name; -ella, a diminutive suffix. Huangnigang, Huangnigang, Jiangshan, Zhejiang. Holotype (Zhejiang; Qiu Hongan et al. 1983) Cephalon and pygidium specimen Cephalon and pygidium specimen (Jiangsu; (Zhejiang; Qiu Hongan et al. 1983) Tripp et al., 1989)

Classification

Order Asaphida / Superfamily Trinucleoidea / Family Dionididae

Genus

Dionidella, subgenus Huangnigangia (Dionidella (Huangnigangia))

Genus author

Han Nairen, Ju Tianyin

Genus etymology

Han & Ju in Qiu et al., 1983

Species

D. (H.) subquadrata Han & Ju in Qiu et al., 1983

Species author

Han Nairen, Ju Tianyin

Species etymology

sub-, Latin, under, slightly, sub-; quadrata, Latin, square

Age

Katian (Late Ordovician)

Distribution

Zhejiang, Jiangsu

Diagnosis

Dorsal shield subovate. Glabella rounded-square, convex, slightly constricted medially, with 2 pairs of glabellar furrows: one pair short and deep, perpendicular to the occipital ring, the other pair pit-like at the median constriction; two small median nodes present: one behind the middle and one in front of the occipital furrow, stouter than the former; occipital ring transversely narrow; preglabellar area wide; a pair of small triangular basal lobes at the posterolateral part of the glabella; cheeks with irregular radiating wrinkles, extended into stout spines. Thorax of 6 segments, the first macropleural. Pygidium subsemicircular; axis long-conical, with 18 rings, the posterior two faint; pleural and interpleural furrows of the pleural region distinct.

Remarks

This species is the type species of the subgenus Dionidella (Huangnigangia).