Abstract
ABSTRACT Collema leptosporum was originally included in Collemataceae as part of the Collema fasciculare group, an informal group that also included C. fasciculare, C. papuanorum, and C. uviforme. However, molecular data from C. fasciculare showed that this species belongs to Arctomiaceae, and all species in this informal group were relocated to Arctomia, although no molecular data were generated and analyzed for C. leptosporum, C. papuanorum and C. uviforme. To investigate the phylogenetic relationships of Collema leptosporum, currently Arctomia leptospora, we analyzed three DNA loci and examined morphological and anatomical features of specimens collected near the type locality. Genetic data suggest that this species is not included in Arctomiaceae and should be treated as a new genus in Collemataceae. Hondaria gen. nov. is characterized by having the longest transversely-septate ascospores in the family ((100-)120-175(-200) × 2-4(-5) µm). This study also suggests that the structures characterizing the C. fasciculare group are a result of convergent evolution, since this group includes species from different distantly related species.
Highlights
The landscape of the west-central region of Brazil, especially near the border with Bolivia and Paraguay, is composed of a mosaic of vegetation formations that include the Pantanal wetlands, the Brazilian savanna (Cerrado) and the Chaco (Pott & Pott 1994)
This study suggests that the structures characterizing the C. fasciculare group are a result of convergent evolution, since this group includes species from different distantly related species
Our phylogenetic analysis showed that Arctomia leptospora is not a member of Arctomia, Gabura (Arctomiales) or Collema
Summary
The landscape of the west-central region of Brazil, especially near the border with Bolivia and Paraguay, is composed of a mosaic of vegetation formations that include the Pantanal wetlands, the Brazilian savanna (Cerrado) and the Chaco (Pott & Pott 1994). More than 20 new species were described by the Swedish botanist Gustaf Malme (Spielmann & Canêz 2012), including the jelly lichen Collema leptosporum (Collemataceae, Peltigerales; Malme 1924). This species was originally reported from Corumbá subsequently from the Campo Grande municipality in Brazil (Oliva et al 1992; Prado et al 1999), and from the Chaco region in Paraguay (Degelius 1974). The ascospores of Collema leptosporum are acicular and transversely septate, like C. fasciculare, C. papuanorum, and C. uviforme These species were included in an informal subgeneric group, the C. fasciculare group, due to the combination of a “crustose” thallus with corticicolous habit and the very long ascospores (Degelius 1974). All four species were excluded from the Collemataceae (Peltigerales) and transferred to Arctomia (Arctomiaceae, Arctomiales), due to the phylogenetic placement of Marcos Junji Kitaura, Mayara Camila Scur, Josiane Vogel Cortina Theodoro, Ana Cláudia Piovezan-Borges and Aline Pedroso Lorenz
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