On the Cryptic Speciation in the Mosses with East Asia-East North America Disjunction: A Case Study of Two Poorly Understood Mosses from the Southern Extremity of the Russian Far East

Abstract

A survey of the moss flora of the southernmost part of the Russian Primorsky Territory yielded several intriguing taxa, whose identity is assessed herein based on an integrative morpho-molecular approach. Bellibarbula recurva was previously known in inland Asia only from the Sino-Himalayan region and the new locality is distant from the earlier known ones to ca. 3000 km. Despite the morphological uniformity, Russian specimens are remarkably distinct in sequences of all three obtained DNA markers, approaching an American specimen in the rps4 sequence. Another probable relic, Symblepharis cf. crispifolia, appeared to be fairly common in the southern part of the Primorsky Territory, where low mountains are covered with hard-leaved forests. Russian specimens of Symblepharis cf. crispifolia var. brevipes show significant divergence from S. crispifolia s.str., which also has complex phylogenetic structure, obscuring further taxonomic implications. The description and illustrations of both taxa based on Russian specimens are provided, and the area, where both species occur, is briefly characterized; it includes numerous thermophilous species, which are rare or do not occur northwards. Our case study uncovers the problem of cryptic speciation within species distributed in temperate climate and is considered to represent relics of Arcto-Tertiary flora.

Keywords: DNA barcoding; arcto-tertiary flora; biodiversity; biogeography.

Figure 1

Habitat of Bellibarbula cf. recurva and Symblepharis crispifolia in southern extremity of Russian Far East. (A) Mramornaya Mt., view from summit; (B) rock outcrops with Lycopodioides tamariscina and Hypnum leptothallum and spots of bare soil—characteristic ecotope where Bellibarbula cf. recurva occurs.

Figure 2

Bayesian phylogenetic trees, showing affinities of target groups of specimens (marked with “!”). (A): Bellibarbula cf. recurva inferred from the combined plastid rps4-trnS and trnM-trnV dataset; (B) Symblepharis crispifolia var. brevipes inferred from the combined cp trnF-trnT, rps4-trnS, trnG, mt Nad5, and nr ITS dataset. Bayesian posterior probabilities inferred from the datasets with indels coded using a simple indel coding approach, and Bootstrap values obtained from 1000 pseudoreplicates of ultrafast bootstrapping are shown above the branches.

Figure 3

Line drawings of gametophyte of Bellibarbula recurva (from: Russia, Primorsky Territory, Fedosov & Pisarenko MW9133374): (A) habit, dry; (B) habit, wet; (C,G,I–K,N) stem leaves; (D,E) upper leaf cells; (F) stem transverse section; (H) median laminal cells; (L,M) leaf transverse sections; (O) basal leaf cells. Scale bars: 2 mm for (A,B); 1 mm for (C,G,I–K,N); 100 µm for (D–F,H,L,M,O).

Figure 4

Line drawings of sporophyte and gametophyte of Symblepharis crispifolia s.str. (A,E–G,J,N–Q from Russia, Primorsky Territory, Lazarenko 20.X.1933) and “S. crispifolia var. brevipes” (B–D,H,I,K–M from Russia, Primorsky Territory, Lazovsky Reserve, 24.IX.1987 Bardunov et al., VLA): (A–C) habit, dry; (D) stem transverse section; (G) upper leaf cells; (E) median laminal cells; (F,K–P) leaf transverse sections; (J) cells of leaf shoulder; (K–P) stem leaves; (Q) basal leaf cells. Scale bars: 5 mm for (A); 3 mm for (B); 2 mm for (C); 1 mm and 200 µm for (K–P); 100 µm for (F,H,I); 50 µm for (D–J,Q).