Nereimyra, BLAINVILLE, 1828

Pleijel, Fredrik, Rouse, Greg W. & Nygren, Arne, 2012, A revision of Nereimyra (Psamathini, Hesionidae, Aciculata, Annelida), Zoological Journal of the Linnean Society 164 (1), pp. 36-51 : 39-41

PHYLOGENY OF NEREIMYRA

PHYLOGENETIC ANALYSIS

The combined data set of COI, 16S rDNA, 28S rDNA, and 18S rDNA consisted of 3832 aligned positions. Amongst the 3646 characters left after excluding alignment ambiguous regions, 1088 are variable, whereof 596 are parsimony-informative. The resulting majority rule consensus tree from the Bayesian analysis has 11 nodes with posterior probabilities (PP) ± 0.95 ( Fig. 1 ). The results from the analyses on the separate mitochondrial and nuclear data sets are largely congruent with the combined analysis. There is a single conflicting node with PP ± 0.95 amongst the analyses where Leocrates chinensis Kinberg, 1866 and Ophiodromus flexuosus (Delle Chiaje, 1825) are sister taxa in the mitochondrial phylogenetic tree (PP = 1.0), but consecutive sisters to the remainder hesionids in the phylogenetic trees based on the nuclear (PP = 0.95) and the combined data sets (PP = 0.98). Both separate and combined analyses favour Syllidia armata Quatrefages, 1866 as the sister taxon to a monophyletic Nereimyra (PP = 1.0 for both nodes in all analyses), and a closer relationship between N. punctata ( Müller, 1776) and N. woodsholea ( Hartman, 1965) than either of them has to N. aphroditoides ( Fabricius, 1780) (PP = 0.99, 0.82, 0.98 in mitochondrial, nuclear and combined data sets, respectively).

POPULATION GENETIC ANALYSIS

The COI data set consists of 658 aligned positions. Including only Nereimyra terminals, 160 characters are variable of which 153 are parsimony-informative. Of those, 19 occur in the first position, and 134 in the third position. Three of the substitutions separating N. aphroditoides from N. punctata and N. woodsholea result in amino acid changes in amino acid positions 139, 152, and 153. There is also a single amino acid changes within N. woodsholea in amino acid position 198. The mean Kimura two-parameter (K2P)- corrected distance between N. aphroditoides and N. punctata is 23.0 ± 0.1% (range 22.7–23.2%), the mean K2P-corrected distance between N. aphroditoides and N. woodsholea is 20.1 ± 0.3% (range 19.7–

A B C

20.8%), and the K2P-corrected distance between N. punctata and N. woodsholea is 16.6 ± 0.3% (range 16.0–17.4%). There are three haplotypes in both N. aphroditoides and N. punctata , and six haplotypes in N. woodsholea ( Fig. 2 ). Mean intraspecific variation is 0.47 ± 0.36% (range 0–0.94%) in N. aphroditoides , 0.15 ± 0.15% (range 0–0.48%) in N. punctata , and 0.76 ± 0.49% (range 0–1.8%) in N. woodsholea . Haplotypes are shared between specimens from Greenland and Svalbard in N. aphroditoides , and between specimens from Norway and Sweden in N. punctata , whereas for N. woodsholea the closest haplotypes for specimens from Norway and Sweden are separated by a single mutation ( Fig. 2 ). The 16S data set for Nereimyra terminals consists of 503 aligned positions and there are no inferred indelevents present. Of 33 variable characters, 14 are parsimony-informative. The mean K2P-corrected distance between N. aphroditoides and N. punctata is 5.1 ± 0.1% (range 4.9–5.1), the mean K2P-corrected distance between N. aphroditoides and N. woodsholea is 5.6 ± 0.4% (range 5.0–5.8), and the K2P-corrected distance between N. punctata and N. woodsholea is 3.1%. Amongst the four specimens that were sequenced for N. aphroditoides t here are two haplotypes, separated by a single mutation, whereas only single specimens were sequenced for N. punctata and N. woodsholea . The 28S data set for Nereimyra terminals consists of 786 aligned positions; there are no inferred indel-events present. Of 13 variable characters, 12 are parsimony-informative. The mean K2Pcorrected distance between N. aphroditoides and N. punctata is 2.1 ± 0.0%, and the mean K2Pcorrected distance between N. aphroditoides and N. woodsholea is 1.7 ± 0.0%. A single mutation separates N. punctata and N. woodsholea (K2P-corrected distance = 0.16%). A single haplotype was found in the three specimens that were sequenced for N. aphroditoides whereas only single specimens were sequenced for N. punctata and N. woodsholea . 18S rDNA was only sequenced for N. punctata amongst the Nereimyra terminals.

Figures

Figure 1. Bayesian majority rule consensus tree from the combined analysis. Posterior probabilities ± 0.95 shown.

Figure 2. Haplotype networks for cytochrome oxidase c subunit 1. A, Nereimyra aphroditoides. B, Nereimyra punctata. C, Nereimyra woodsholea. Each bar across a line connecting two specimens denotes one mutation. Numbers correspond to specimens numbers in Table 1, and letters indicate origin (G, Greenland; M, Middle Atlantic Bight; N, Norway; S, Sweden; V, Svalbard).