Lecanora stenotropa Nyl.

Rosa, Iris Nadia De La, Passo, Alfredo, Rodríguez, Juan Manuel, Chiapella, Jorge Oscar & Messuti, María Inés, 2016, A new species and new records of Lecanora (Lecanoraceae, lichenized Ascomycota) with usnic acid from the Antarctic region, Phytotaxa 261 (2), pp. 185-193 : 190-191

Lecanora stenotropa Nyl.

Fig. 3B

This species has a yellowish, pale yellow-green thallus, plane to slightly convex areoles, strongly convex apothecia, with yellowish to brownish discs. It is easily confusable with L. polytropa , a species widely distributed in Antarctica. Although both species have been studied by many authors, its circumscription is still unresolved ( LaGreca & Lumbsch 2001; Śliwa & Olech 2002; Ryan et al. 2004; Śliwa et al. 2012). The extreme variability of L. polytropa difficult the clarification of morphological differences between two species, since it may develop intermediate morphotypes overlapping with some thallus of L. stenotropa . Formerly, they also were separated by the containing of rangiformic acid (in L. polytropa ) or isorangiformic acid (in L. stenotropa ). Nevertheless, HPTLC analysis have demonstrated that these species are chemically indistinguishable; both producing usnic, rangiformic, isorangiformic acids and sometimes zeorin. The most reliable character to separate these species is the ascospore shape, being narrowly ellipsoid in L. stenotropa (8–13 × 4–5 μm) and broadly ellipsoid in L. polytropa (8–13 × 4–8 μm). It is likely that L. stenotropa has been overlooked in the Antarctic collections, previously identified as L. polytropa .

After a detailed observation of the L. stenotropa specimens dealt with in the present paper, some rare morphological variations caused by extreme environmental conditions in Antarctica have been registered. In this habitat the mentioned species develops scanty, with areoles only around the apothecia, to well-developed thalli, superficial and extended, dispersed to ±continuous, verrucose, often forming rosette-like structures, with plane to slightly convex and emarginated apothecia, yellowish orange, pale orange, pale yellow, generally crowded in clusters.

Lecanora stenotropa was reported for Europe (e.g. Spain, Italy, British Isles), North America ( Canada), South America ( Bolivia) and New Zealand ( LaGreca & Lumbsch 2001; Crespo et al. 2003; Ryan et al. 2004; Edwards et al. 2009; Śliwa et al. 2012). The present is the first record of the species for the Antarctic region.

Along with L. intricata and L. polytropa , L. stenotropa is considered as a member of the L. polytropa group, one of the least studied subgeneric groups within Lecanora that lacks taxonomic treatment ( Śliwa & Flakus 2011). Due to notorious variability of this species group, a thorough survey of it and related species is required.

Specimens examined:— ANTARCTIC PENINSULA. Danco Coast: Primavera Station, Punta Cierva , near big penguin nests, on rock, elev. 167 m, 64°09′39.7″S, 60°57′15.3″W, 10 February 2014, A. Passo & J. M. Rodríguez ( BCRU 5380 ) ; ibid., near the base, 10° west-facing slopes close sea shore, between Deschampsia antarctica E. Desv. and bryophytes, on rock, elev. 17 m, 64°09′17.9″S, 60°57′23.0″W, 11 February 2014, A. Passo & J. M. Rodríguez ( BCRU 5389 ).— SOUTH SHETLAND ISLANDS. King George Island : Potter Peninsula, 300 m west of Carlini Station , mature community, 62°14′25.5″S, 58°40′30.7″W, 16 February 2014, A. Passo & J. M. Rodríguez ( BCRU 5383 ) .

Figures

FIGURE 3. Habitus of the new records of Lecanora in the Antarctica. A. L. intricata (BCRU 5385). B. L. stenotropa (BCRU 5380). Scale = 1 mm.