A Cladistic Analysis of the Genus Diploschistes (Ascomycotina, Thelotremataceae)

Abstract

The phylogeny of the genus Diploschistes is investigated using parsimony analysis with morphological, chemical, and ecological characters. The scruposus group, including D. ocellatus, is supported as monophyletic, whereas the actinostomus group is shown to be paraphyletic. The predicted trend from perithecioid to urceolate ascomata within the genus is supported. The lichen genus Diploschistes Norman is a small genus in the Thelotremataceae Zahlbr. containing approximately 30 species (Lumbsch & Guderley 1996). It is usually distinguished from other genera in that family by the combination of the following characters: presence of a Trebouxia Puymaly photobiont (most other genera contain Trentepohlia Martius), blackish pigmentation of the pseudoparenchymatous excipulum, presence of lateral paraphyses, and absence of a columella (Guderley et al. 1997; Lumbsch 1989). The genus is widely distributed in arid and semiarid areas and occurs mainly on rocks and soil, although facultatively corticolous species are also known. The related genera having Trentepohlia as the photobiont have their centre of distribution in the wet tropics and are often corticolous. Monographic studies on this genus were initiated in 1982 by one of us (HTL) and the revision of taxa from several regions and species groups were prepared together with several colleagues (Abu-Zinada et al. 1986; Guderley & Lumbsch 1996; Lumbsch 1987, 1988, 1989, 1993; Lumbsch & Aptroot 1993; Lumbsch & Elix 1985, 1989; Lumbsch & Mayrhofer 1990; Mies & Lumbsch 1990). In addition, a revision of the species of Diploschistes in India was published (Pant & Upreti 1993), and a revision of the Australasian species is in preparation by Lumbsch and Elix. The results of these taxonomic studies are summarized in a multi-entry key to Diploschistes species (Lumbsch & Guderley 1996), available via Internet (http://www.botanik.biologie.uni-muenchen.de/ botsamml/lias/modules.html). For an exhaustive treatment of the systematic position, characters, and history of taxonomic exploration, the reader can refer to other papers (Lumbsch 1989; Lumbsch et al. 1997). Cladistic methods have been used in systematic studies of different groups of the lichenized ascomycetes (e.g., Hyvionen et al. 1995; Kmrnefelt et al. 1992; Lutzoni & Brodo 1995; Tehler 1983, 1990, 1993a, 1993b, 1994b, 1995, 1997; Tehler & Egea 1997; Wedin 1993) and an overview of the application of cladistics in ascomycete systematics has been prepared by Tehler (1994a). However, no phylogenetic analysis in the Thelotremataceae has been published. Over a decade ago, at an IAL meeting in Miinster, some preliminary ideas about evolutionary trends in the genus Diploschistes were presented (Lumbsch 1986). These evolutionary trends were deduced from a phylogenetic tree prepared manually. Since then, computer programs developed for cladistic analysis have completely altered the basis for reconstructing phylogenies. To gain a better knowledge of the characters in the genus and with modern computer programs now available for the search of most parsimonious trees, a cladistic analysis of the genus has now been carried out. The object of this contribution is to discuss the relationships in the genus Diploschistes on b sis of the results obtained from the present cladistic analysis as compared to the results formulated by Lumbsch (1986). MATERIALS AND METHODS The study is based on herbarium material of Diploschistes and related genera in the Thelotremataceae from numerous herbaria, including AK, ASU, , BCC, BM, BRI, CANB, CHR, COLO, DUKE, E, ESS, FH, FI, G, GZU, H, HBG, HO, IMI, KOELN, L, LD, M, MB, MEL, O, OTA, PC, S, STU, TUR, U, UPS, US, W, WELT, WRSL, WU, and the private herbaria of A. Aptroot (Baarn), K. Kalb (Neumarkt/Opf.), H. T Lumbsch (Essen), and A. Vezda (Brno). One of us (HTL) has also collected and studied material of most Diploschistes species in the field. For details on methods, refer to earlier publications (e.g., Lumbsch 1989). Cladistic analysis.-All morphological, anatomical, and chemical character data used for the cladistic analysis were assembled from direct examination of specimens; no unconfirmed literature data were used. Unfortunately, no materi l of D. awasthii Pant & Upreti or D. nepalensis 0007-2745/98/398-403$0.75/0 This content downloaded from 157.55.39.91 on Wed, 21 Sep 2016 04:58:16 UTC All use subject to http://about.jstor.org/terms 1998] LUMBSCH & TEHLER: CLADISTICS OF DIPLOSCHISTES 399 TABLE 1. Characters used in the analysis and character states. Habitat and nutrition