Vermilacinia lacunosa Spjut & Sérus., 2020

Spjut, Richard, Simon, Antoine, Guissard, Martin, Magain, Nicolas & Serusiaux, Emmanuel, 2020, The fruticose genera in the Ramalinaceae (Ascomycota, Lecanoromycetes): their diversity and evolutionary history, MycoKeys 73, pp. 1-68 : 1

Vermilacinia lacunosa Spjut & Sérus. sp. nov. Fig. 13C, D

Diagnosis.

Similar to V. reptilioderma morphologically by the cylindrical-prismatic branches and chemically by the triterpenes T1 and T2, but differing in chemistry by the additional lichen substance, methyl 3,5-dichlorolecanorate (tumidulin).

Type.

Mexico - Baja California Sur, Vizcaíno Peninsula, 2.5 km SE of Punta Eugenia, rock outcrops along coastal hills trending west-east separated by wide arroyo, just east of the coastal community of La Lobera; 27°49.701'N, 115°03.454'W; alt. 35-40 m; 29.01.2016, R. Spjut & E. Sérusiaux 17174 leg.; on calcareous rocks of north facing slope; (LG! - holotype; BCMEX!; US!; hb. Spjut at World Botanical Associates! - isotypes) [TLC: Triterpenes 1 & 2, zeorin, [-]-16α-hydroxykaurane, usnic acid, methyl 3,5-dichlorolecanorate (= tumidulin), two unknown triterpenes; DNA: MN811420 (ITS), MN757203 (RPB1), MN757370 (RPB2), MN757488 (GDP)]

Description.

Thallus divided into many subcylindrical branches from a basal reddish-brown to blackish holdfast, to 2.5 cm high and broad. Primary branches ascending to erect, ± ellipsoid-arcuate in x- section, simple or once dichotomously divided near mid region, terminating in aggregate of up to 8, commonly 5, apothecia or with single apothecium, or apothecia not fully developed on most branches, occasional branches without apothecia tapering to obtusely rounded apex; surface of branches commonly lacunose, deeply recessed within reticulate or circular cortical ridges when dry. Cortex pale yellow green, 50-125 μm thick, each of two layers equal in thickness, outer melanized, inner pale. Medulla hyphae flexuous when wet, intertwining in a net arrangement, ± periclinal, frequently uniting into short knots; photobiont in small yellow green clusters irregularly discontinuous around perimeter. Apothecia subsessile, differentiated from branch by constriction or very short stalk-like lobe, bowl-shaped, to 2 mm diam. Alternatively, wider with shallower disc in age, thalline margin not differentiated by thicker cortex, incurved, entire or crenulate with age, disc pale yellow green or yellowish with age, concave; asci 8-spored; spores not observed outside asci. Pycnidia black, common on upper branches and on apothecia, mostly along cortical ridges, immersed except for ostiole flush with surface, conidia straight, short, needle-like.

Chemistry.

Triterpenes 1 & 2, zeorin, [-]-16α-hydroxykaurane, usnic acid, methyl 3,5-dichlorolecanorate (tumidulin), unknown triterpenes just below and above T1 and T2, respectively (TLC solvent G).

Distribution and ecology.

Mexico, Baja California Sur, Vizcaíno Peninsula. Known only from a single collection on calcareous rocks on the north slope facing towards a wide arroyo just inland from the sea on the far western Vizcaíno Peninsula, occurring with Vermilacinia paleoderma and vascular plants Fouquieria diguetii , Pachycormus discolor , Eriogonum pondii and Gossypium sp. This region lies within the El Vizcaíno Biosphere Reserve, the largest reserve in Mexico. Additional details on the vegetation of the Vizcaíno Peninsula can be found in Peinado et al. (2005).

Etymology.

Epithet lacunosa refers to the cortical depressions or ‘holes’ in the branch.

Remarks.

Vermilacinia lacunosa is a distinct saxicolous species for containing the rare lichen metabolite methyl 3,5-dichlorolecanorate (tumidulin), identified by its high Rf on TLC plates in two specimens, previously known only from South American epiphytic species of Vermilacinia ( Spjut 1996), such as V. flaccescens (Nyl.) Spjut and Hale. Sipman (2011) subsequently reported finding what he interpreted to be tumidulin in a new sorediate species he named Niebla granulans , here regarded as Vermilacinia [ V. granulans (Sipman) Spjut and Sérusiaux (comb. nov.); bas. Niebla granulans Sipman, Bibliotheca Lichenologica 106: 300, 2011] found on twigs at Zapallar in the Valparaíso region of Chile. He distinguished it by apical punctiform soralia in contrast to lateral disciform soralia of V. cephalota ; he further differentiated it from V. cephalota by the intricately branched habit; however, Spjut has collected much branched V. cephalota near Bahía de Asunción and distinguished V. leonis in the Magadlena Region of Baja California Sur for its larger much branched thalli ( Spjut 1996). Additionally, Sipman (2011) reported four undetermined terpenoid compounds, one of which was likely a diagnostic Vermilacinia compound, [-]-16α-hydroxykaurane, based on his observation of "blooming of terpenoid crystals in herbarium specimens." The species was noted to lack chondroid strands, pycnidia and apothecia.

In contrast, Sipman (2011) described Niebla nashii , another Chilean sorediate species from Coquimbo that he compared to Ramalina lacera (With.) J. R. Laundon. He distinguished it by possessing isolated medullary chrondroid strands, as well as tumidulin and bourgeanic acid, while he also noted that key [ Vermilacinia ] terpenoids, pycnidia and apothecia were absent. Judging from Sipman’s image of the type specimen, it lacks the characteristic cortical ridging of Niebla . Further, Sérusiaux et al. (2010) found bourgeanic acid associated with depsides in Mediterranean species of Ramalina - that had been treated in Niebla by Rundel and Bowler (1978) and Bowler and Marsh (2004) - to be nested within the genus Ramalina . Other collections identified Niebla spp. from Patagonia in Chile (National Park of Torres Del Paine) - that were reported to contain tumidulin - "exhibited significant inhibitory activity on spheroid formation in CRC cells and decreased the expression of CSC markers in CRC cells" ( Yang et al. 2018). DNA extracts are needed to assess the phylogenetic relationships of the Chile specimens reported to contain tumidulin.

Conservation Status.

The type locality of Vermilacinia lacunosa , 2.5 km southeast of the fishing community of Punta Eugenia, is vulnerable to off-road travel. Spjut observed the Punta Eugenia community to have expanded considerably since his first visit there in 1986. Although the type locality lies within the El Vizcaíno Biosphere Reserve, this reserve is referred to as a wildlife refuge. However, to the northeast is the protected area of flora and fauna at Valle de los Cirios in the southern portion of Baja California. "The El Vizcaíno overlaps with smaller protected areas on land and in the waters, including the protected grey whale ( Eschrichtius robustus ) sanctuaries at Ojo de Liebre ( Scammon’s Lagoon), Guerrero Negro, and San Ignacio. Protection is provided by international organizations including UNESCO, Ramsar and Western Hemisphere Shorebird Reserve Network (WHSRN). The area is not only important to plant and animal life, but more than 300 ancient rock painting sites have been discovered throughout the reserve" (CONANP-20: http://www.parkswatch.org/parkprofile.php?l=eng&country=mex&park=vibr&page=inf&p=mex; accessed 09.06.2019).

Figures

Figure 13. New species of saxicolous Vermilacinia A, B V. breviloba (holotype) C, D V. lacunosa (holotype) E, F V. pustulata (holotype) G, H V. reticulata (holotype). Scale: 1 mm (A, C). Photographs by R. Spjut.