Figure 4
From: Ringiculid bubble snails recovered as the sister group to sea slugs (Nudipleura)
Time-calibrated phylogeny of euthyneuran gastropods.
Reconstruction was based on concatenated four-gene sequences (3,679 sites) and four calibration priors on node ages and performed in BEAST. Numerals on branches denote Bayesian posterior probabilities (BPP); asterisks denote maximum value (1.00). Arrow points to age of earliest fossil occurrence of unambiguous Ringiculidae (Ringicula buchholzi), which bore a thickened outer lip of shell (plausibly a derived condition within the family). Filled and open circles indicate presence and absence of thickened lip, respectively, in modern ringiculids; note independent losses in putatively polyphyletic Microglyphis. Estimated nodal ages (in million years ago, Mya) and 95% credibility intervals (HPD) for first split within clades: Acteonacea, 256 (HPD: 196–315); Ringipleura, 270 (223–321); Tectipleura, 244 (210–279); Rissoelloidea, 128 (72–185); Acteonoidea, 115 (55–181); Ringiculoidea, 195 (141–250); Nudipleura, 212 (158–265); Euopisthobranchia, 198 (190–213); Panpulmonata, 228 (198–261).
