Ophiocordyceps camponoti-atricipis Araújo, H.C. Evans & D.P. Hughes, 2015

Araújo, João P. M., Evans, Harry C., Geiser, David M., Mackay, William P. & Hughes, David P., 2015, Unravelling the diversity behind the Ophiocordyceps unilateralis (Ophiocordycipitaceae) complex: Three new species of zombie-ant fungi from the Brazilian Amazon, Phytotaxa 220 (3), pp. 224-238 : 227-229

Ophiocordyceps camponoti-atricipis Araújo, H.C. Evans & D.P. Hughes , sp. nov. ( Fig.2 )IF 550743.

Differs from other members of the O. unilateralis clade by the host (always Camponotus atriceps ), ascospore morphology and germination. Stroma usually velvety at the basal part when mature.

Type: — BRAZIL. Amazonas: Reserva Adolpho Ducke, 2° 57’ 42”S, 59° 55’ 40” W, 100 m, on Camponotus atriceps F. Smith , 10 January 2012 J.P.M. Araújo & H.C. Evans A-56, ( INPA 261937, holotype!, FEM 90326, isotype!).

External mycelium abundant, covering most of the host, produced from all orifices and sutures; initially white, turning light-brown. Stroma single, produced from dorsal pronotum, averaging 15–20 mm, up to 25 mm in length, cylindrical, velvety and ginger brown at the base, becoming cream-pinkish towards apex; fertile region of lateral cushions, 1–2, hemispherical, chocolate brown, darkening with age, variable in size, averaging 1.5 × 0.5-0.8 mm. Perithecia immersed to partially erumpent, flask-shaped, 240–280 × 100–150 μm, with short, exposed neck or ostiole. Asci 8-spored, hyaline, cylindrical to clavate, 110–140 × (4.5–) 6–6.5 (–8) μm; prominent cap, (3.5–) 5 × 5.5 (–6.5) μm. Ascospores hyaline, thin-walled, vermiform (75–) 80–85 (–100) × (2–) 3 (–3.5) μm, 5-septate, sinuous to curved, never straight at maturity, rounded to acute apex.

Etymology: Named after the ant host, Camponotus (Myrmothrix) atriceps F. Smith.

Asexual-morph: — Hirsutella-like A type only, produced on the upper stromatal surface; phialides cylindrical to lageniform, 5–7 × 2–3 μm, tapering to a long neck, 5–11 μm; conidia not seen. This asexual morph occurs in all the species included here and is not considered to be critical for species separation. Hence, it is not analyzed in detail.

Germination process: —The released ascospores germinated within 24–48 h, producing 1–2, uniformly straight, thread-like structures (capilliconidiophores); typically of uniform length and averaging 55 μm; bearing a single terminal spore (capilliconidium), hyaline, smooth-walled, allantoid and tapering at the ends at maturity, 10–11 × 2–2.5 μm, narrowing apically.

Habitat:— Brazilian Central Amazon. Hosts commonly found biting the apical part of palm-fronds, but also on dicot leaves, rarely on palm-spines; abundant mycelial growth from the mouthparts helping to fix the host to the leaf, in addition to the locked jaws.

Additional specimens examined (paratypes): — BRAZIL. Reserva Adolpho Ducke: Manaus, 2° 57’ 42”S, 59° 55’ 40” W, 100m elevation, 12 January 2012, Araújo, H.C. Evans & D.P. Hughes, A35 (INPA 261940!).

Figures

FIGURE 2. Ophiocordyceps camponoti-atricipis a) Single stroma, characteristic of Ophiocordyceps unilateralis sensu lato, with a single lateral ascoma, arising anteriorly from pronotum of Camponotus atriceps, firmly attached to the edge of the leaf (bar = 3 mm); b) Detail of fertile region (ascoma) (bar = 0.8 mm); c) Section through ascoma showing the mainly immersed perithecial arrangement (bar = 200 μm); d) Ascospore with a needle-like outgrowth (capilliconidiophore) producing terminal conidium (bar = 20 μm); e) Close-up of conidium (bar = 10 μm); f) Close-up of perithecium (bar = 50 μm); g) Ascus, clavate in shape and with a prominent cap (bar = 20 μm); h) Section of upper part of stroma showing asexual morph (Hirsutella-like A type), with a palisade of subulate phialides (bar = 10 μm) Images: João Araújo.