Gibellula aurea, Mendes-Pereira & Araújo & Mendes & Fonseca & Alves & Sobczak & Góes-Neto, 2022

Mendes-Pereira, Thairine, Araújo, João Paulo Machado De, Mendes, Flávia Carvalho, Fonseca, Emily Oliveira, Alves, Julie Erica Da Rocha, Sobczak, Jober Fernando & Góes-Neto, Aristóteles, 2022, Gibellula aurea sp. nov. (Ascomycota, Cordycipitaceae): a new golden spiderdevouring fungus from a Brazilian Atlantic Rainforest, Phytotaxa 573 (1), pp. 85-102 : 91-95

Gibellula aurea sp. nov. T. Mendes-Pereira, J.P.M. Araújo & A. Góes-Neto, Figs. 1 and 2 .

Mycobank number: —842796

Type: — BRAZIL. Ceará: Pacoti, Sítio São Luís, Trilha do Purgatório, 910 m elevation, 4°13’21” S, 38°53’35” W, 21 December 2019, collected by: Alves, J. E. R., on spider Macrophyes pacoti (Anyphaenidae) , deposited at the collection Herbário da UFMG–Fanerógamas, algas e fungos (BHCB); holotype: BHCB205962 , paratypes: BHCB205963; BHCB205964; BHCB205966 .

Etymology: —from Latin, aurea : adjective of aurum, in allusion to the colour of gold. Named after the goldenyellow colour of the subiculum, which is characteristic of this species.

Diagnosis: — Gibellula aurea exhibits typical yellow hyphae, with white conidiophores ( Fig. 1a ), differing from other species previously described in the genus.

Habitat: —Brazilian Atlantic Rainforest, Ceará State, Brazil.

Hosts: —Spider species of the families Corinnidae (6.5% of the collected hosts)( Fig. 2a, b ) and Anyphaenidae (87% of the collected hosts), including M. pacoti (comprising 69% of the hosts)( Fig. 2c, d ); other 6.5% of the hosts were not identified. Host size 1.51–5.24 mm (min–max) long (N=14). Hosts were found attached to the abaxial surface of leaves in plants up to approximately 3 m high above the soil. No specific fungal structure attaching the host to the substrate was found.

Description: — Mycelium golden-yellow, completely covering the spider host ( Fig. 1a, k, l ). Synnemata goldenyellow, solitary or up to three, 0.81–4.92 mm long × 0.09–0.27 mm wide (N=16), with a short stipe and fertile area ( Fig. 1a , arrow), which consists of a network of anastomosed hyphae, hyaline, septate, terminating in an inflated fertile tip ( Fig. 1b, h ). Conidiophores numerous, white, arising directly from the subiculum or produced along the synnemata, scattered, verrucose, hyaline, 86.56–319.88 (434.97) µm long × 6.52–17.64 µm wide at the base (N=33), aspergillate, narrowing to a slender apex (3.12–8.08 µm wide), and terminating in a swollen vesicle ( Fig. 1c ). Conidial heads globose, white, 28.84–47.94 µm diam. (N=46). Vesicles ellipsoidal, (6.63) 8.53–15.57 µm long × 5.95–10.76 µm wide (N=15), hyaline, smooth, bearing several metulae ( Fig. 1d ). Metulae ellipsoidal to obovoidal, hyaline, numerous, 5.47–12.27 µm long × 3.56–10.08 µm wide (N=130), borne on vesicle. Phialides cylindrical, 5.10–8.95 µm long × 1.5–3.57 µm wide (N=140), often apically thickened, smooth-walled, hyaline ( Fig. 1d ). Conidia ellipsoidal, according to the length/width ratio ( Largent et al. 1977), with apiculate ends, smooth-walled, hyaline, 2.54–3.97 µm long × 1.78–2.90 µm wide (N=51) ( Fig. 1e, j ). Granulomanus -like synanamorph conidiogenous cells (arrow) at the bases of conidiophores ( Fig. 1g ). Conidiophores observed at the surface of the host body, especially on the legs ( Fig. 1f, i ). Conidial head hemispherical, bearing ellipsoidal vesicle and metulae, distinct from the spheric conidial head found in most conidiophores. Conidia cylindrical to filiform ( Fig. 1f ), 8.67–18.82 µm long × 0.79–1.56 µm wide (N=23). Sexual morph not observed.

Additional specimens examined: — BRAZIL. Ceará: Pacoti, Sítio São Luís, Trilha do Purgatório, 910 m elev., 4°13’21” S, 38°53’35” W, 21 December 2019, on spider M. pacoti, Alves, J. E. R. (#01; 04; 05; 06; 09; 10; 11; 12; 15; 16; 21; 22; 23; 27; 29; 30; 31; 33; 34; 35; 41; 42). Ibid. on spider Corinnidae, Alves, J. E. R. (#24; 25; 40; 43). Ibid. 18 January 2020, on spider M. pacoti, Alves, J. E. R. (#124; 125; 126; 128; 130). Ibid. 30 June 2021, on spider M. pacoti, Fonseca, E. O. (#08; 09, 10, 12). Paratype: Ibid. 03 April 2022, on spider M. pacoti, Fonseca, E. O. , deposited at the collection Herbário da UNILAB, (HU), HU1275, Collector number: EOF001.

Specimens sequenced directly from the host: LBMCF0003: spiders #01, 25, 33, 125, 128; LBMCF0004: #34, 35, 124, 126; LBMCF0006: #04; 06, 11, 15, 23, 31; LBMCF0007: #05, 22, 36, 29, 130; LBMCF0008: #04, 27; LBMCF0009: #30; LBMCF0010: #41.

Molecular phylogeny

We obtained sequences of the genomic regions SSU (n=3), LSU (n=3), TEF (n=7), and RPB2 (n=4) from specimens of G. aurea using DNA directly extracted from synnemata ( Table 3 ). The 91 sequences of Gibellula from this study and previous studies included in the analyses clustered in eight clades, most exhibiting high support for both phylogenetic searches ( Fig. 3 ; Fig. S1 ). The phylogenetic trees generated by ML ( Fig. 3 ) and BI ( Fig. S1 ) using the combined dataset showed similar topologies for most of the clades, with posterior probabilities and bootstrap values higher than the threshold set (ML>50%, BI>0.70); especially for those specimens identified at the species level. The newly proposed species G. aurea clustered in a clade with different support for each topology, which displayed a bootstrap value of 87% and posterior probability of 1 (Clade V; Fig. 3 ). Furthermore, nine species formerly described clustered in delimited clades ( Fig. 3 ): G. longispora (Clade II), G. pigmentosinum (Clade III), G. gamsii (Clade IV), G. cebrennini / G. fusiformispora (Clade VI), G. dimorpha / G. trimorpha (Clade VII), and G. scorpioides / G. penicillioides (Clade VIII).

Intra- and interspecific genetic variation

The specimens of G. aurea displayed lower intraspecific than interspecific distances for the four genomic regions (SSU: F (1,118) =81.69, p<0.001; LSU: F (1,593) =961.984, p<0.001; TEF: F (1,1324) =5632.558, p<0.001; RPB2: F (1,210) = 2559.837, p<0.001; Fig. 4 ), which confirms the hypothesis of a new species initially suggested by morphological and phylogenetic analyses. Species that have been recently described with sequences for most of the genomic regions ( Chen et al. 2021, 2022; Kuephadungphan et al. 2019, 2020, 2022) also showed lower intraspecific than interspecific distances for the genomic markers shown here. Some sequences described only at the genus level were closer to described species, such as G. pulchra and G. leiopus , which might help to clarify the identity of these specimens ( Fig. 4 ). The dataset of the RPB2-coding gene displayed higher genetic distances among the markers for the genus ( Fig. 5 ; Table S3 ) but still displayed a barcode gap. Moreover, the LSU and TEF regions showed better-delimited groups.

Figures

FIGURE 1. Morphological description of Gibellula aurea. (a) Spider Macrophyes pacoti (Anyphaenidae) parasitized by G. aurea exhibiting one synnema (arrow) growing from the host’s abdomen. (b–g) G. aurea visualized in the light microscope and (h–l) in the fluorescent microscope with UV light. (b, h) Inflated and fertile tip of synnema; (c) Conidiophore, stipe with verrucose wall, conidial head spherical; (d) Conidial head globose, vesicle ellipsoidal, metulae ellipsoidal, and phialides cylindrical; (e, j) Conidia ellipsoidal, with apiculate ends; (f, i) Granulomanus-like conidiophores; (g) Conidiogenous cells; (k) Spider leg (brown) covered by hyphae (blue) at the beginning of the infection; (l) Setae of spider leg involved by fungal hyphae. Scale bars: b, k, h = 100 µm, l = 50 µm, c, d, e, f, g, i, j = 10 µm.

FIGURE 2. Diversity of host spiders parasitized by Gibellula aurea. (a) and (b) Corinnidae; but differ by abdomen shape, body size, and shape of the front legs; (c) Macrophyes pacoti (Anyphaenidae); (d) Anyphaenidae. Scale bars: a, b, c, d = 1 mm.

FIGURE 3. Placement of Gibellula aurea within the genus. Phylogenetic trees were based on concatenated sequences of SSU, LSU, TEF, and RPB2 markers. This tree topology resulted from a Maximum Likelihood, although Bayesian Inference displayed the same topology for most of the clades (Fig. S1). Numbers on branches indicate bootstrap values (ML>50%) followed by posterior probabilities (BI>0.70). Nucleotide substitutions per site are indicated by the scale bar. The phylogenetic tree includes 33 SSU, 63 LSU, 77 TEF, and 37 RPB2 sequences. Sequences from GenBank are exhibited by the name followed by their voucher numbers. For G. aurea specimens sequenced in this study, we show the name in bold (code: LBMCF). Formerly described species that split into single clades were also highlighted. The species Hevansia novoguineensis (NHJ 11923) was used as an outgroup.

FIGURE 4. Genetic distance within the genus Gibellula. Heatmaps were generated with sequences from each genomic region obtained from GenBank and the specimens from this study. Genetic distances between sequences are displayed from the lowest (red) to the highest (blue) distance. (a) Genetic distance within the small nuclear ribosomal subunit (SSU); (b) within the large nuclear ribosomal subunit (LSU); (c) translation elongation factor 1-α (TEF); and (d) RNA polymerase II second largest subunit (RPB2). Closer sequences are connected by the dendrogram on top and left in each heatmap.

FIGURE 5. Intra- and interspecific genetic distances among sequences. (a) Proportion of intra- and interspecific of each genomic region (SSU, LSU, TEF and RPP2); (b) interspecific genetic distances among the sequences identified at the species level within the closest clade to Gibellula aurea.