Piptocephalidaceae

Overview

Classically, the Piptocephalidaceae has contained two genera, Piptocephalis and Syncephalis, each with 29 and 47 described taxa, respectively (Kirk, 1978; Benjamin, 1985b). Although these two genera were included in the Cephalidaceae by many early mycologists (Fischer, 1892; Zycha, 1935; Naumov, 1935, 1939) or the Piptocephalidaceae (SchrÃ¶ter, 1893; Hesseltine, 1955; Mil’ko, 1974) they were often classified with unrelated fungi: Syncephalastrum (Mucoraceae; Mucorales), and members of the Dimargaritaceae (Dimargaritales) and Kickxellaceae (Kickxellales). Benjamin (1959) was the first to demonstrate that the only true members of the Piptocephalidaceae are Piptocephalis and Syncephalis, and this concept has been followed by most subsequent workers (Zycha et al., 1969; Hesseltine and Ellis, 1973; Benjamin, 1979).

Benjamin (1979) transferred the Piptocephalidaceae from the Mucorales (Benjamin, 1959; Hesseltine and Ellis, 1973) to the Zoopagales because of similarities in merosporangiospore formation, zygospore morphology (especially gametangial enlargement), and all of these organisms are haustorial parasites.

Most spp. of the Piptocephalidaceae are parasites of the Mucorales but some taxa are known to be or suspected of being parasites of Deuteromycetes or Ascomycetes, including: Piptocephalis xenophila Dobbs & English (Dobbs and English, 1954), Syncephalis sphaerica van Tiegh. (Baker et al., 1977), and S. wynneae Thaxter (1897).

Dung is the supposed substrate of choice for the isolation of members of the Piptocephalidaceae, and the merosporangiferous Mucorales in general. Rodent dung, especially the dung of omnivorous rats and mice, has been a rich source of these fungi (Benjamin, 1959, 1966). Many workers have also isolated members of this group from soil (Dobbs and English, 1954; Indoh, 1962; Richardson and Leadbeater, 1972; Kuzuha, 1973, 1976; Kirk, 1978; Bawcutt, 1983; Benjamin, 1985a, 1985b). Richardson and Leadbeater (1972) have provided data that demonstrates that Piptocephalis, and especially Syncephalis, are common in litter and the “A” and “B” soil horizons and not as frequent on dung as is commonly supposed. They compared soil and litter (388 samples) with sheep dung (14 samples), and no Piptocephalis spp. were encountered but 14 isolates of Syncephalis were made from the latter substrate. Rodent dung might have provided a higher number of Piptocephalidaceae spp.

Members of the Piptocephalidaceae can isolated almost any substrate, especially dung and soil, that will support the growth of a suitable host.

Classification

Piptocephalidaceae SchrÃ¶ter, 1893 (In Engler and Prantl, Die natÃ¼rl. Pflanzenfam. 1(1): 132)

Haustorial parasites of fungi, especially Mucorales. Sporophore simple or branched, coenocytic or septate, bearing merosporangia directly on unswollen tips of branches or on swollen, thick-walled deciduous or nondeciduous apices (head-cells). Merosporangia containing one to many sporangiospores, moniliform, resulting from acropetal budding, and disarticulating at maturity, or cylindrical, spores formed simultaneously and merosporangial wall evanescent or persistent and released with the spores by circumscissile rupture. Zygospores formed on apposed, parallel or entwined gametangia, lobate outgrowths sometimes formed from one suspensor.

Type genus: Piptocephalis de Bary.

KEY TO THE GENERA OF PIPTOCEPHALIDACEAE

A. Sporophores unbranched, rarely once or twice dichomously branched, with a nondeciduous terminal fertile vesicle; mycelium often nodose, anastomosing; appressoria large, producing extensive, hyphalike haustoria —— Syncephalis

AA. Sporophores few to many times three-dimensionally dichotomously branched, often with a deciduous or nondeciduous head-cell; mycelium not anastomosing, appressoria small, producing restricted, delicate haustoria —— B

B. Merosporangia moniliform, branched, forming zig-zag chains of spores —— Kuzuhaea

BB. Merosporangia not moniliform, simple or branched; spores one to many; chains of spores straight —— Piptocephalis

Synopsis of Genera

KUZUHAEA Benjamin, 1985 (J. Linn. Soc., Bot. 91: 122).

PIPTOCEPHALIS de Bary, 1865 (Abh. Senckenerg. Naturf. Ges. 5: 356).

Updated Feb 10, 2005