Heterocypsela brachylepis (Compositae: Vernonieae: Dipterocypselinae), a new species from the Brazilian dry forest
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ISSN: 0075-5974 (print) ISSN: 1874-933X (electronic)
Heterocypsela brachylepis (Compositae: Vernonieae: Dipterocypselinae), a new species from the Brazilian dry forest D. Marques1, D. T. Iglesias2, R. Fonseca2 & J. N. Nakajima1
Summary. Limestone or calcareous outcrops are geological formations that support tropical forests regarded as relict communities with many endemic species. However, these environments are constantly threatened by mining of calcareous rock. The genus Heterocypsela H.Rob. (Compositae, Vernonieae: Dipterocypselinae) has been longknown from only one species which is endemic to Brazilian limestone outcrops in the State of Minas Gerais. During field work on limestone outcrops of northern Minas Gerais, a second species of Heterocypsela was discovered. This species is described in the genus Heterocypsela since it has relatively long-pedunculate heads, dimorphic cypselae with only cubic crystals, glandular apical anther appendages and echinolophate type “C” pollen. Further investigation in herbarium specimen databases (Specieslink and Herbario Virtual Reflora) revealed other specimens of a new species, Heterocypsela brachylepis J.N.Nakaj. & D.Marques, expanding its geographic distribution to southwestern Bahia and southeastern Tocantins States in Brazil, in the same habitat. Heterocypsela brachylepis is described and illustrated. Despite its wide geographic distribution, this species should be considered Critically Endangered (CR), criterion D according to the IUCN guidelines, due to its restricted occurrence and few individuals. Key Words. Asteraceae, calcareous rock, karst outcrops, endemic species, mining, taxonomy.
Introduction Karst or limestone outcrops are biologically important because they have a wealth of endemic species (Cowling et al. 1994; Xu 1995; Willis et al. 1996a, b; BardotVaucoulon 1997; Médail & Verlaque 1997; Vermeulen & Whitten 1999; Tuyet 2001; Zhu et al. 2003; Clements et al. 2006; Hart 2007; Espírito Santo et al. 2018). These outcrops present very specific environmental conditions such as alkaline, shallow and rich soils, with large amounts of calcium, magnesium and potassium (Arruda et al. 2015), high temperatures and solar incidence and low availability of water (Espírito Santo et al. 2018). Due to these characteristics, the dry forest that grows on these outcrops is highly specialised and tolerant to these extreme conditions, however, it is also very susceptible to environmental disturbances (Médail & Verlaque 1997). Since calcareous outcrops are composed mainly of calcium carbonate (Radam Brasil 1982), it is possible to extract limestone, an important raw material used in the cement industry (Clements et al. 2006). This mining, in conjunction with other human impacts, threatens the unique plant diversity of these outcrops (Vermeulen & Whitten 1999; Clements et al. 2006; Day 2010a, b; Coelho et al. 2012; Melo et al. 2013). The tropical dry forests are the most threatened terrestrial ecosystem on the planet (Janzen 1988).
In South America, less than 2% of the territory has
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