Triglypta jiyuanensis Liao & Huang, 2023

Liao, Huan-Yu, Fang, Shao-Hua, Feng, Zhuo, Gao, Jian & Huang, Di-Ying, 2023, A new clam shrimp (Branchiopoda: Diplostraca: Spinicaudata) from the Upper Jurassic in the Jiyuan Basin, China and its biostratigraphic significance, Zootaxa 5396 (1), pp. 50-57 : 52

Triglypta jiyuanensis Liao & Huang sp. nov.

urn:lsid:zoobank.org:pub:5FAACDA1-59A9-4DDE-AB7B-8CE71A74B5FB

( Figs 2 , 3 )

Material. Holotype, NIGP203506 , a complete individual . Paratypes, NIGP203503–203505 , 203507–203508 .

Etymology. After the Jiyuan City, from where the specimens were collected.

Diagnosis. Carapace round to oval, with a small larval valve; dorsal to middle area of the carapace ornamented with sparse micro-punctae; linear arrangements of punctae and radial lirae present at the middle to anterior part of the carapace.

Type locality and horizon. Maao Formation near the Anyao Village , Jiyuan City; lowermost Upper Jurassic (Oxfordian) .

Description. Carapace round to oval in outline, moderate in size (L= 4.2–6.1 mm, 5.1 mm in average; H= 2.9–4.6 mm, 3.8 mm in average; H/L=0.65–0.80, 0.73 in average; Fig. 2 ); larval valve small; umbo in medial and marginal position ( Fig. 2 ); dorsal margin very short and slightly arched; growth bands fine and densely distributed, 22–28 in number (24 in average; Fig. 2 ); growth bands ornamented with micro punctae (2–5 μm in diameter; Fig. 3 ); punctae sparse distributed at the upper to middle part of the carapace ( Fig. 3A, B ); punctae gather together to form linear arrangements at the middle to anterior part ( Fig. 3C–H ); linear arrangements extremely prominent at the anterior part ( Fig. 3E, G, H ); each linear arrangement formed by two rows of punctae ( Fig. 3D, F, G ); radial lirae present between linear arrangements ( Fig. 3D, F, G ); linear arrangements and radial lirae not prominent at the posterior part of the carapace.

Figures

FIGURE 2. Carapaces of Triglypta jiyuanensis Liao & Huang sp. nov. A, Showing a left valve NIGP203503. B, Showing a left valve NIGP203504. C, Showing a right valve NIGP203505. D, Showing a left valve NIGP203506. Scale bars = 1 mm.

FIGURE 3. Ornamentations on the carapaces of Triglypta jiyuanensis Liao & Huang sp. nov. A, Sparse punctae at the middle part NIGP203503. B, Sparse punctae at the upper to middle part NIGP203507. C, Linear arrangments and radial lirae at the anterior part NIGP203507. D, Enlargement of the punctae and linear arrangements at middle-anterior part on an external mold NIGP203508. E, Linear arrangements and radial lirae at the anteroventral part NIGP203507. F, Enlargement showing each linear arrangement was formed by two rows of punctae, and the lirae between the linear arrangements NIGP203507. G, Linear arrangements and radial lirae at the middle ventral part on an external mold NIGP203506. H, Radial lirae at the anteroventral part NIGP203505.