Freshwater transitions and symbioses shaped the evolution and extant diversity of caridean shrimps

Abstract

Understanding the processes that shaped the strikingly irregular distribution of species richness across the Tree of Life is a major research agenda. Changes in ecology may go some way to explain the often strongly asymmetrical fates of sister clades, and we test this in the caridean shrimps. First appearing in the Lower Jurassic, there are now ~3500 species worldwide. Carideans experienced several independent transitions to freshwater from marine habitats, while many of the marine species have also evolved a symbiotic lifestyle. Here we use diversification rate analyses to test whether these ecological traits promote or inhibit diversity within a phylogenetic framework. We demonstrate that speciation rates are more than twice as high in freshwater clades, whilst symbiotic ecologies are associated with lower speciation rates. These lower rates amongst symbiotic species are of concern given that symbioses often occur in some of the most diverse, delicately balanced and threatened marine ecosystems.

Phylogenetic supertree and functional trait database for all extant parrots

“…Supertrees exist for many taxa, such as dinosaurs [9] , [10] , birds [11] , mammals [12] , crocodiles [13] , crustacean decapods [14] , [15] , [16] and grasses [17] . They allow fast and efficient synthesis of existing phylogenetic information (known as source trees), without the resources required for constructing complete molecular phylogenies [18] .…”

Mushroom Body Homology and Divergence across Pancrustacea

“…In the Crangonidae, Crangon franciscorum has a mushroom body-like calyx and columnar lobes, whereas its sister species Paracrangon echinata has a bulbous hemiellipsoid body-like center and a diminutive lobe ( Figures 10C,D,11). Crangon and Paracrangon, which occupy different habitats (see below), are estimated to have diverged in the early Eocene, about 56 mya (Davis et al, 2018).…”

“…The following descriptions include only a small number of the species belonging to lineages used for molecular phylogenomic reconstruction (see Schwentner et al, 2018;Wolfe et al, 2019). We have also referred to analyses that focus on mantis shrimps (Van der Wal et al, 2017), as well as decapods, including stenopods (cleaner shrimps), alpheids and carideans ("visored shrimps", "pistol shrimps": Anker et al, 2006;Anker and Baeza, 2012;Bracken et al, 2010;Davis et al, 2018), brachyurans ("true crabs": Tsang et al, 2014), thalassinids ("ghost shrimps": Tsang et al, 2008), anomurans including "hermit crabs" (Bracken-Grissom, 2014a;Chablais et al, 2011), and various clades that colloquially are referred to as lobsters (see Shen et al, 2013;Bracken-Grissom, 2014b). Figure 1B summarizes the disposition and shapes of anti-DC0immunoreactive centers in their lateral protocerebra.…”

“…Here, we consider marine species belonging to the families Alpheidae and Thoridae (members of the superfamily Alpheoidea), and intertidal species of the family Crangonidae. These families originated approximately 220, 160 and 70 mya, respectively (Davis et al, 2018). Alpheidae is a diverse family that contains snapping shrimps, commonly referred to as pistol shrimps, which include the only known crustaceans to have evolved eusociality (Duffy et al, 2000), and visored shrimps closely related to the genus Alpheus (Anker et al, 2006).…”

“…The genus Crangon is here represented by the sand shrimp Crangon franciscorum and the horned shrimp Paracrangon echinata, belonging to the superfamily Crangonoidea, which originated at the end of the Cretaceous (Davis et al, 2018). Both species provide interesting comparisons with the alpheids with respect to their habitat and mode of life.…”