Figure 3
From: Exceptional appendage and soft-tissue preservation in a Middle Triassic horseshoe crab from SW China
Book gills of Yunnanolimulus luopingensis and extant horseshoe crabs. (A) LPI-60564, an individual with preserved book gills and pusher legs; frame indicates close-up shown in (G). (B) LPI-61734, enlargement of opisthosomal part with book gills; frame indicates close-up shown in (E). (C) LPI-40709, showing the book gills and movable spines; frame indicates close-up shown in (F). (D) Five pairs of book gills of the extant Tachypleus tridentatus, note the operculum was removed. Provided by Shuigen Hong; (E), (F), (G) enlargement of frames in (B), (C), (A) respectively, showing details of respiratory lamellae. The following abbreviations are used: opc2-opc5, second to fifth gill opecula; bg, book gills; ms, movable spines; opc: genital operculum; yct, yellow connective tissue. Scale bars: 10 mm in A; 5 mm in (A–C); 2 cm in D; 500 μm in (E–G).
