Fig 1.
Minimum age phylogenetic tree of Penaeoidea.
Agripenaeina, the clade of farmed shrimp, acquired a large body size despite the physiological constraints of their warm and shallow-water habitats. This clade is at least 145 my old because it includes a Late Jurassic species (†Antrimpos speciosus) that inhabited the warm waters preserved in the Late Jurassic Solnhofen limestone [14,15]. Ecological associations between shallow-water penaeoideans and mangrove forests occurred independently more than once, as clades of mangrove-associated shrimp (e.g., Agripenaeina and Trachypenaeini) predate the proposed Late Cretaceous origin of modern mangroves [16]. Shrimp silhouettes illustrate differences in maximum body size for each clade. Topology shown emerges from parsimony (strict consensus of 24 trees) and Bayesian analyses, with some Bayesian incongruences noted in the Extended Results. Topology mapped to stratigraphic record with range extensions (cones) dictated by fossil placements (black dots indicate first appearance datum in the stratigraphic record) [17]. Bremer Support (blue) and jackknife values over 50% (green) are indicated. Values in parentheses were calculated without fossil taxa (fossil exclusion produces a congruent tree). Bayesian posterior probabilities in black, with values italicized for clades that are congruent except for the placement of †Aeger tipularius, which occupies a different position in the Bayesian tree (see S4 Fig). Tree icon and vertical shading indicate earliest evidence of modern mangroves [16].
Fig 2.
Members of Agripenaeina and Trachypenaeini from the Late Jurassic.
†Antrimpos speciosus (panels a and b, CM-33420) and †Drobna deformis (panels e and f, CM-29467), fossils from the Solnhofen limestone, Germany (ca. 145 mya [18]) preserve key features that link them phylogenetically to shallow-water penaeoideans. †Antrimpos speciosus belongs to Agripenaeina, the clade accounting for 90% of shrimp farmed for human consumption, and is shown in comparison to Penaeus monodon (c, giant tiger shrimp), a living member of Agripenaeina. †Drobna deformis is the sister taxon of Sicyonia (Trachypenaini), and is shown in comparison to the living Sicyonia lancifer (g, rock shrimp). d and h show derived features shared by fossil and living shrimp. Additional synapomorphies for all clades are listed in S2 and S3 Tables. Scale bars = 3 cm.
Table 1.
Gills and epipods in Penaeoidea.
Among the shallow-water clades, Agripenaeina (and other members of Penaeini) have the highest number of gills and epipods. Deep-water clades have the highest numbers across all of Penaeoidea. Listed are the total numbers of gills and epipods per side, based on the ancestral states for each clade, using parsimony. App = associated appendix, Max = maxilliped, Per = pereiopod.