Morphological species of Gloeandromyces (Ascomycota, Laboulbeniales) evaluated using single-locus species delimitation methods

Abstract

In this paper, new species and formae of the genus Gloeandromyces (Ascomycota, Laboulbeniales) are described and illustrated. These are: Gloeandromyces dickii sp. nov. on Trichobius joblingi from Nicaragua and Panama; G. pageanus f. alarum f. nov. on Tri. joblingi from Panama; G. pageanus f. polymorphus f. nov. on Tri. dugesioides and Tri. joblingi from Panama and Trinidad; and G. streblae f. sigmomorphus f. nov. on Tri. joblingi from Panama. Gloeandromyces pageanus on Tri. dugesioides from Panama as described in Nova Hedwigia 105 (2017) is referred to as G. pageanus f. pageanus. Support for these descriptions of species and formae comes from phylogenetic reconstruction of the large subunit ribosomal DNA and from the application of species delimitation methods (ABGD, bPTP, GMYC). Host specialization results in phylogenetic segregation by host species in both G. pageanus and G. streblae and this may represent a case of incipient speciation. A second mechanism driving diversity involves position-induced morphological adaptations, leading to the peculiar morphotypes that are associated to growing on a particular position of the integument (G. pageanus f. alarum, G. streblae f. sigmomorphus).

Keywords: ectoparasitic fungi; host specialization; phenotypic plasticity; ribosomal DNA; taxonomy.

Fig. 1.

Field sites where the streblid bat flies (Diptera, Streblidae) were collected that hosted the Gloeandromyces species and formae described in this paper. Field sites are located in Nicaragua and Panama in Central America; Ecuador in South America; and Trinidad, the southernmost island in the Caribbean.

Fig. 2.

Maximum clade credibility tree showing species in the genus Gloeandromyces, with Stigmatomyces protrudens as outgroup (adapted from Haelewaters et al. 2018b). The tree is the result of a Bayesian analysis of the LSU dataset. For each node, ML BS (≥ 70)/Bayesian pp (≥ 0.7) are presented above the branch leading to that node. Symbols indicate hosts: (bat flies) = Megistopoda aranea, = Trichobius dugesioides, = Tri. joblingi; (bats) = Artibeus jamaicensis, = Carollia brevicauda, = C. perspicillata, = Trachops cirrhosus. Symbols behind fungus species names designate morphotypes: *Gloeandromyces streblae f. sigmomorphus, ^G. pageanus f. alarum, all other isolates in clade D: G. pageanus f. polymorphus. To the right of the terminal labels of the phylogeny, SDM results are summarized, from left to right: ABGD of the aligned LSU data matrix with prior intraspecific divergence (P) = 0.001 (Pmin), ABGD with P = 0.002783, ABGD with P = 0.01 (Pmax), bPTP of the LSU topology and GMYC of the LSU ultrametric tree generated in BEAST. To the right of the SDM results, thalli of Gloeandromyces spp. are shown. From top to bottom: Gloeandromyces nycteribiidarum; G. dickii; G. streblae and *G. streblae f. sigmomorphus; G. pageanus f. pageanus (clade C), and ^G. pageanus f. alarum and G. pageanus f. polymorphus (clade D).

Fig. 3.

Thalli of Gloeandromyces dickii. A. Mature thallus from slide FH 00313692 (holotype), with arr owheads pointing at outgrowths typical for this species. See description for details. B. Mature thallus from slide FH 00313694, with the perithecium less ovoidal and the anteriorly directed perithecial outgrowth halfway the venter shorter and more tapered in comparison to the type series. C. Mature thallus from slide FH 00313693 (with the perithecial venter ruptured anteriorly). Annotated are cells I, II, III, VI, VII, and the pentagonal-shaped basal cell of the appendage (bca). Scale bars: A = 50 µm, B–C = 20 µm.

Fig. 4.

Thalli of Gloeandromyces pageanus. A–B. Gloeandromyces pageanus f. pageanus. A. Mature thallus from slide FH 00313698 (paratype). B. Mature thallus from slide FH 00313700 (paratype), showing perithecial details on the posterior side: two horn-like projections (arrows) and two bulbous outgrowths (arrowheads). C–D. Gloeandromyces pageanus f. alarum. C. Mature thallus from slide FH 00313707 (paratype), releasing ascospores. D. Mature thallus from slide FH 00313709 (paratype), showing upper perithecial venter details: two conspicuous bumps (arrowheads) and a tapering projection directed posteriorly (arrow). Asterisks (*) highlight the two preostiolar bumps at opposite sides. E–F. Gloeandromyces pageanus f. polymorphus, mature thalli from slide FH 00313706 (paratype). E. Mature thallus, with annotated cells I, II, III, VI, VII, and the basal cell of the appendage (bca). F. Detail of mature thallus, showing antheridial cells (arrows) and conspicuous bumps at the distal end of the perithecial venter (arrowheads). Scale bars: A, C, E = 50 µm; B, D, F = 20 µm.

Fig. 5.

Thalli of Gloeandromyces streblae f. sigmomorphus. A. Mature thallus from slide FH 00313703 (paratype). B–C. Details of mature thallus from slide FH 00313704 (holotype). B. Details of receptacle, appendage, and perithecial base, with annotated cells I, II, III, VI, VII, n’, and the basal cell of the appendage (bca). C. Details of upper perithecium, with conspicuous rounded bumps at the distal end of the perithecial venter (arrowheads) and the very large preapical outgrowth (arrow). Scale bars = 50 µm.

Fig. 6.

A specimen of a Trichobius bat fly, photographed in situ dorsally (left) and ventrally (right). Annotated (encircled or with arrow) are the positions of the bat fly cuticle at which some (morpho-)species of Gloeandromyces seem to be restricted to: G. dickii on the abdomen, ventrally, at the right side; G. pageanus f. alarum at the base of both wings; and G. streblae f. sigmomorphus at the last tergite/sternite. Scale bars = 100 µm. Images provided by André De Kesel.