Fig. 4. Callichimaeraperplexa n. gen. n in Exceptional preservation of mid-Cretaceous marine arthropods and the evolution of novel forms via heterochrony

Fig. 4. Callichimaeraperplexa n. gen. n. sp., reconstruction. (A and B) Line drawing of dorsal (A) and ventral (B) views. Colorsdenoteconvergent traitswith other decapod groups: light gray, dorsal carapace, similar to some lobsters and †Palaeocorystidae (Brachyura: Raninoida); dark gray, large eyes, similar to †Ekalakia (Dromiacea: †Glaessneropsidae) and several homoloids; red, pediform mxp3 bearing acrista dentata, similarto lobsters, most anomurans, and early-branching brachyurans (Homolodromioidea, most Homoloidea); yellow, spanner-like P1, similar to Hippoidea (Anomura), Raninoidea (Brachyura), and †Retrorsichela; green, flattened paddle-like legs P2 and P3, similar to Matutidae (Brachyura: Eubrachyura); blue, reduced legs P4 and P5, as in hermit crabs (Anomura: Paguroidea), podotreme brachyurans (e.g., Homolodromioidea and Cyclodorippoidea) and early-branchingeubrachyurans (e.g., Dorippoidea); orange, sternites S5 and S6 similar to †Retrorsichela, and Heikeopsis (Eubrachyura: Dorippoidea); and purple, symmetrical pleon lacksarticulatedrings anduropods/uropodal plates, likemost brachyurans. (C and D) Digital reconstruction. (C) Dorsal view. (D) Ventralview. A, pleon; Cx, coxa;Is, ischium; Ma, manus. Scalebar,10 mm. See movies S1 and S2 anddata file S2 for three-dimensional (3D) viewableand printable models. Line drawings by J.L. and 3D reconstructions by A.D.