Mycologia, 95(4), 2003, pp. 685–687. ᭧ 2003 by The Mycological Society of America, Lawrence, KS 66044-8897

Another fossil from Dominican

David S. Hibbett1 Etymology. The generic name means ‘‘golden mush- Manfred Binder room’’; the epithet refers to the collection locality. Zheng Wang 3 mm broad, convex, with a broad raised Department of Biology, Clark University, 950 Main center, glabrous or minutely textured, yellow-brown; St., Worcester, Massachusetts 01610 margin incurved, striated. Lamellae subdistant; mar- gins smooth; lamellulae or anastomoses absent; at- Yale Goldman tachment not observed. central, 0.8 ϫ 7 mm, 86 Dunne Ave., Collinsville, Connecticut 06019 cylindric, smooth; annulus, volva and rhizoids absent. 3.5–4.4 ϫ 3.0–3.5 ␮m, broadly elliptic. HOLOTY PE: DOMINICAN REPUBLIC: El Valle, Abstract: We report the discovery of a fossil agari- Yanigua mine. In the private collection of Yale Gold- coid homobasidiomycete from Dominican amber (ca man (s.n.). 15–20 Ma). Aureofungus yaniguaensis appears to be a Aureofungus yaniguaensis is an agaricoid homoba- member of the euagarics , but its precise taxo- sidiomycete. The vast majority of such forms occur nomic placement is obscure. This is the fourth in the euagarics clade (ϭ pro parte), known fossil agaric and the third from Dominican which contains about 8500 described (Hawk- amber. sworth et al 1995, Hibbett and Thorn 2001). The Key words: Agaricales, Aureofungus yaniguaensis, shape and stature of the fruiting body suggest that A. euagarics clade, paleomycology yaniguaensis might be related to the smaller pale- spored genera traditionally classified as - taceae (e.g., (Fr.) Staude, (Pers.) Three fossil are known to science. Coprinites Roussel, Fr., Murrill), or dominicana Poinar and Singer and Protomycena electra perhaps certain non-deliquescent, dusky-spored taxa Hibbett, Grimaldi and Donoghue are both from Do- (e.g., disseminatus (Pers. : Fr.) J. E. minican amber and are 15–20 million years old (Ma), Lange). Unfortunately, the anatomical characters while leggeti Hibbett, Grimaldi and that would be needed to resolve the placement of A. Donoghue is from Atlantic Coastal Plain amber and is yaniguaensis could not be observed. Because of the 90–94 Ma (Grimaldi, Beck and Boon 1989, Poinar and thickness of the amber it was not possible to view the Singer 1990, Hibbett et al 1995, 1997, Iturralde-Vinent specimen with greater than a 10 ϫ objective, which and MacPhee 1996). Here, we report the discovery of made it difficult to assess the ornamentation of the a fourth fossil agaric (FIGS. 1–5), which was collected and the surface textures of the pileus and in the Yanigua mine in the eastern Dominican Re- stipe. The spores appear to be pigmented (FIG. 3), public and purchased from an amber dealer living in which would suggest a relationship to extant chro- the town of El Valle in August 2000. A single fruiting mosporic groups, but this could be an artifact of pres- body is present (FIGS. 1–2, 4), as well as many basid- ervation or an optical effect of the amber. Lacking iospores that are laid down in masses, suggesting that evidence of its precise taxonomic placement, we sug- they were produced by the fruiting body in the amber gest that A. yaniguaensis should be classified as incer- (FIGS. 3, 5). Based on comparisons to Coprinites Poinar tae sedis among the Agaricales, euagarics clade. and Singer, Protomycena Hibbett, Grimaldi and Don- Although it is not possible to precisely place A. oghue and Archaeomarasmius Hibbett, Grimaldi and yaniguaensis, sufficient characters can be seen to dis- Donoghue, we conclude that the fossil represents a tinguish it from Coprinites dominicana, Protomycena previously undescribed and species. electra and Archaeomarasmius leggeti. The pileus of Co- Aureofungus yaniguaensis Hibbett, Binder and prinites dominicana (Poinar and Singer 1990) was de- Wang, gen. et sp. nov. scribed as squamulose-pectinate with a pleated or grooved margin and a small depression in the center, Accepted for publication September 8, 2002. whereas that of A. yaniguaensis is smooth or glabres- 1 Corresponding author. E-mail: [email protected] cent, with faint striae and a broad raised central area.

685 686 MYCOLOGIA

FIGS. 4–5. Aureofungus yaniguaensis. 4. Fruiting body. 5. Basidiospores. Scale bars: 4 ϭ 100 ␮m, 5 ϭ 4 ␮m.

previously described fossil agarics, there are no char- acters (synapomorphies) that provide positive sup- port for such a relationship. Therefore, we think it is appropriate to classify A. yaniguaensis in a new genus. FIGS. 1–2. Aureofungus yaniguaensis fruiting body. Scale Fossil evidence (Archaeomarasmius) indicates that bar ϭ 100 ␮m. the euagarics clade is at least 90 million years old (Hibbett et al 1995), and molecular clock studies sug- gest that the basidiomycetes as a whole could be any- In addition, the hymenophore of Coprinites is re- where from 500 million years to 1.2 billion years old ported to have lamellulae, which are absent in A. yan- (Berbee and Taylor 2001, Heckman et al 2001). Itur- iguaensis. Finally, the spores of Coprinites differ from ralde-Vinent and MacPhee (1996) suggested that all those of A. yaniguaensis in being larger (6–7 ␮m Dominican amber was formed in a single sedimen- long) and oblong-elliptic. Protomycena electra (Hib- tary basin during a 5 million year interval in the Mio- bett et al 1997) differs from A. yaniguaensis in having cene (15–20 Ma; contra Poinar and Singer 1990). a more campanulate pileus with a reflexed margin, Thus, A. yaniguaensis does not affect the minimum and more distant lamellae with lamellulae and anas- age estimates for either the euagarics clade or the tomoses. Archaeomarasmius leggeti (Hibbett et al basidiomycetes. Nevertheless, fossil fungi in Domini- 1995, 1997) differs from A. yaniguaensis in having a can amber, such as A. yaniguaensis, are of value for more strongly sulcate pileus and larger spores (6.5– understanding the ecology of ecosystems in 8.3 ϫ 4.0–5.2 ␮m). The differences described above the Caribbean and could help evaluate certain his- certainly warrant recognition of A. yaniguaensis as a torical biogeographic hypotheses (see Hibbett 2001 new species. While we cannot rule out the possibility for an example). The discovery of a third fossil agaric that A. yaniguaensis is closely related to any of the from Dominican amber suggests that many more such finds might lie in store.

ACKNOWLEDGMENTS We are grateful to David Grimaldi, who examined the spec- imen and commented on its authenticity, and Scott Red- head, who made valuable editorial suggestions.

LITERATURE CITED

Berbee ML, Taylor JW. 2001. Fungal molecular evolution: trees and geologic time. In: McLaughlin DJ, McLaughlin EG, Lemke PA, eds. The mycota VII sys- tematics and evolution. Part B. Berlin: Springer-Verlag. p 229–245. FIG. 3. Aureofungus yaniguaensis basidiospores. Scale Grimaldi D, Beck CW, Boon JJ. 1989. Occurrence, chemical bar ϭ 10 ␮m. characteristics and paleontology of the fossil resins HIBBETT ET AL: FOSSIL AGARIC FROM DOMINICAN AMBER 687

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