Linglongtaestheria daxishanensis, Ng & Tri, 2023

Li, Gang, 2020, New Spinicaudatan Species of Late Jurassic Linglongta Phase of Yanliao Biota from Western Liaoning, China, Zoological studies 59 (36), pp. 1-8 : 3-6

Linglongtaestheria daxishanensis gen. and sp.

nov. ( Figs. 3 , 4 ) urn:lsid:zoobank.org:act:03DAF083-4D79-4FB6-BAE8-1B8A17268873

Material examined and dimensions: Holotype, displaced carapaces, NIGPCAS 163667 (L1–1); a right valve, NIGPCAS 163668 (L2–1); a broken right valve, NIGPCAS 163669 (L2–2); displaced carapaces, NIGPCAS 163670 (L2–3). Carapace measurements: number of growth lines,> 16, 24, 23, 17; length (mm), 4.6, 5.2, 3.6, 3.7; height (mm), 2.9, 3.3, 2.3, 2.5.

Etymology: From Daxishan, a village located in the south-west of Linglongta.

Diagnosis: Carapace of small or small moderate size; ovate or elliptical in outline; growth lines smooth, about 20 in total; growth bands near the umbo ornamented with fine, polygonal reticulation (diameter <20 µm); growth bands in the middle part of the carapace ornamented with evenly distributed puncta (diameter <5 µm); in the ventral part of the carapace each growth band is ornamented with puncta in the upper part, which transfer into punctate reticulation in the anterior part and radial lirae in the posterior part of each band.

Description: Carapace small or moderate in size, ovate or elliptical in outline; umbo small, located at the anterior half of the slightly arched dorsal margin; growth lines wide and smooth, about 20 in total; growth bands near the umbo ornamented with polygonal small-diameter reticulation, reticulum diameter is about 8–15 µm ( Figs. 3.2 and 3.4 ; Figs. 4.4 and 4.7 ); growth bands in the middle part of the carapace ornamented with evenly distributed puncta, punctum diameter is about 2–5 µm ( Figs. 3.3 , 4.5 ); growth bands in the lower part of the carapace ornamented with puncta in upper part ( Figs. 3.5 and 3.8 ), and punctate reticulation in lower part of each growth band in the anteroventral part of the carapace ( Fig. 3.8 ), and radial lirae intercalated with two rows of radially aligned puncta in the ventral part of each growth band in the posteroventral part of the carapace ( Figs. 3.5, 3.7 , 4.8 ); near the ventral margin, the punctuate zone is located in the upper 1/4 to 1/5 of each growth band ( Fig. 3.8 ).

Distribution: Lower Upper Jurassic Tiaojishan Formation at Daxishan, Linglongta, Jianchang, northern China.

Figures

Fig. 3. 1–8. Linglongtaestheria daxishanensis gen. and sp. nov. 1, displaced carapaces, holotype, NIGPCAS 163667 (L1–1) (light microscopy). 2, small-sized polygonal reticulation on growth bands near the umbo (SEM). 3, evenly distributed small puncta on growth bands in the middle part of the carapace (SEM). 4, small-sized polygonal reticulation on growth bands in the antero-dorsal part of the carapace (SEM). 5,7, two kinds of ornamentation pattern on growth bands in the postero-ventral part of the carapace, i.e., punctate ornamentation in the upper, radial lirae with two rows of intercalated radially aligned puncta in the lower part of each growth band (SEM). 6, small-sized, polygonal reticulation transitions to radial lirae with intercalated radially aligned puncta on growth bands in the antero-dorsal part of the carapace (SEM). 8, two kinds of ornamentation pattern on single growth bands in the antero-ventral part of the carapace, i.e., puncta in the upper, punctate small-sized reticulation in the lower part of each growth band (SEM). Scale bars: (1) = 1 mm; (2, 5) = 20 μm; (4) = 50 μm; (3, 6–8) = 100 μm.

Fig. 4. 1–8. Linglongtaestheria daxishanensis gen. and sp. nov. 1, a right valve, NIGPCAS 163668 (L2–1) (light microscopy). 2, a broken right valve, NIGPCAS 163669 (L2–2) (light microscope). 3, displaced carapaces, NIGPCAS 163670 (L2–3) (light microscope). 4, small-sized polygonal reticulation on growth bands near the umbo of the specimen in figure 4.1 (SEM). 5, evenly distributed puncta on growth bands in the middle part of the carapace of the specimen in figure 4.1 (SEM). 6, two kinds of ornamentation pattern on growth bands in the postero-ventral part of the carapace of the specimen in figure 4.1, i.e., puncta in the upper and radial lirae with intercalated radially aligned puncta in the lower part of each growth band (SEM). 7, small-sized polygonal reticulation on growth bands in the antero-dorsal part of the carapace of the specimen in figure 4.3 (SEM). 8, two kinds of ornamentation pattern on growth bands in the ventral part of the carapace of the specimen in figure 4.3, i.e., puncta in the upper part and radial lirae with intercalated radially aligned puncta in the lower part of each growth band (SEM). Scale bars: (1–3) = 1 mm; (4) = 10 μm; (5) = 20 μm; (6–8) = 100 μm.