… sort of.
Isaria surinamensis. Good species, bad name.
Beginning with the false premise that all (or almost all) Akanthomyces were pathogenic on Lepidoptera, I pulled up a list of the genus’ accepted taxa on IF and MB earlier this evening. MB listed host substrates for a handful of taxa, with other publications filling in much of the remaining gaps (1)(2)(3)(4)(5)(7). All told, the host associations in Akanthomyces look something like this:
Beetles
A. angustospora (6)
A. coleopterorum (6)
A. brevipes (5)
A. furcatus (5)
A. hypogaeus (5)
A. lathrobii (5)
A. longissimus (5)
Homoptera
A. homoptera (6)
Spiders
A. websteri (6)
A. ovalongatus (4)
A. novoguineensis (4)
A. longisporus (6)
A. koratensis (6)
A. cinereus (6)
A. arachnophilus (6)
A. aranearum (6)
A. novoguineensis (6)
A. ampullifer (4)
Crane Flies
A. ampullifer (6)
Gnats
A. ampullifer (2)
Ants
A. gracilis (6) (3)
Saprotroph
A. johnsonii (7)
This leaves A. aculeatus, A. pistilariformis and A. sphingum; the three spp. of Akanthomyces known to occur on Lepidoptera adults or larvae.
Mains discusses all three taxa in his 1950 Mycologia article (2), suggesting a rather complicated two-tiered synonmy between A. aculeatus, A. sphingum and Cordyceps tuberculata; the lattermost being the known teleomorph of A. pistillariaeformis. The sphingum epithet seems to have been haphazardly applied to both anamorphic and teleomorphic specimens, going under such names as Isaria sphingum, Torrubia sphingum, Hymenostilbe sphingum and Isaria sphingophila. It is Mains’ opinion — and a far more intricately reasoned one than I could attempt to duplicate here — that the anamorph is what he calls Insecticola pistillariaeformis (now Akanthomyces pistillariiformis) and the teleomorph is C. tuberculata. If Mains is right, that leaves A. pistillariaeformis as the only true, anamorphic, Lepidoptera-inhabiting Akanthomyces sp., which cannot be a match for this observation for a variety of reasons, namely the synnemata length of 0.4-1.0 mm.
It was Mains’ sudden mention of a then almost 50- (now 110-) year-old taxon, Isaria surinamensis, that immediately caught my attention:
Vosseler (25) describes I. surinamensis as having synnemata up to 12 cm. long with short side branches bearing conidia 2 μ in diameter.
furthermore…
Speare (18) has suggested that this species is a Hirsutella.
I. surinamensis was first described by Julius Vosseler in 1902(1). The host was Amphonyx cluentus, a species of hawkmoth, collected in the rainforests of Surinam (hence surinamensis). I’ve written a young man who accompanied us in Ecuador for part of the 2010 AMP service learning course, whose very purpose for being in the country was to study Amazonian Lepidoptera, so hopefully we’ll have an ID for the moth in this ob. sometime soon. In the meantime, short of his ID and a soon-to-come full translation of Vosseler’s original description of I. surinamensis (3.5 pages of non-OCR-readble German, for now posted as-is, untranslated, on the taxon’s name page), I believe that name (or Speare’s recombination of it as H. surinamensis) to be the strongest candidate yet. The synnemata length and host similarity alone are promising enough, further supported by what little likeness can be derived from Vosseler’s own 1902 photograph:

If our herbarium specimen still exists at Universidad Central, Quito, there’s a good chance that this could be redescribed comb. nov. as Akanthomyces surinamensis, if needed, depending on the contemporary understanding of the macro- and micromorphology of Akanthomyces vs. Hirsutella.
It bears mentioning that Speare’s appropriating of variously described taxa into Hirsutella wasn’t at all restricted to Vosseler’s I. surinamensis and I. gracilis. He illustrates the Hirsutelloid qualities of several other taxa as well, calling for all of them to be brought out of their random generic placements and into the Hirsutella fold given their collective adherence to the following criteria:
Fruiting bodies in the form of simple or branched, long, erect, slender and rigid, or short verruciform synnemata composed of more or less parallel septate hyphae. Sporophores simple, sessile or subsessile, subulate, the distal portion extremely long and attenuated and sharply set off from the swollen or inflated basal portion. Spores adjointed singly from the tips of the sporophores, fusoid, allantoid or cylindrical in form, hyaline, one- celled, their true shape obscured by a gelatinous substance which surrounds and renders them citriform in appearance. (3)
Another line of inquiry could then be how many taxa currently listed under Hirsutella also possess exceptionally long synnemata, though I get the feeling that if there were anything similar to I. surinamensis, either Mains or Speare would have said so in their respective articles.
The work it took to uncover all of this data strongly evidences the need for a centralized database of mycological literature, one even more comphrehensive than D.W. Minter’s CyberLiber, which most certainly served as an indispensable resource throughout this particular bout of investigation, but was without archives of some of the more esoteric journals in which Akanthomyces taxa were first described. I someday intend to construct that very thing, but that’s another topic for another time.
More to come.
(1)Vosseler, J. “Ueber einige Insektenpilze.” Jahreshefte des Vereins für vaterländische Naturkunde in Württemberg. Bd. 58 (1902): 380-384. Print
(2)Mains, E B. “Entomogenous Species of Akanthomyces, Hymenostilbe and Insecticola in North America.” Mycologia. 42.4 (1950): 566-589. Print.
(3)Speare, A T. “On Certain Entomogenous Fungi.” Mycologia. 12.2 (1920): 62-76. Print.
(4)Hsieh, L S, S S. Tzean, and W J. Wu. “The Genus Akanthomyces on Spiders from Taiwan.” Mycologia. 89.2 (1997): 319-324. Print.
(5)Thaxter, R. “New species of Laboulbeniales from various localities.” Proceedings of the American Academy of Arts and Sciences. 28 (1893): 156-188. Print
(6)http://www.mycobank.org
(7)Vincent, Michael A, Keith A. Seifert, and Robert A. Samson. “Akanthomyces Johnsonii, a Saprophytic Synnematous Hyphomycete.” Mycologia._ 80.5 (1988): 685-688. Print.