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Unitat de Botànica, Departament de Biologia Animal, Biologia Vegetal i d’Ecologia, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193-Bellaterra, Spain
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSTAXONOMYPREVIOUSLY KNOWN SPECIESDISCUSSIONLITERATURE CITED |
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The occurrence of three new species of Harpellales in the Iberian Peninsula is reported. Capniomyces celatus was found in Nemouridae (Plecoptera) nymphs, Stipella latispora in Simuliidae (Diptera) larvae and Legeriomyces dolabrae with Baetidae (Ephemeroptera) nymphs. These species are differentiated from others by thalli and/or reproductive structures. Geographic range extensions for other species of Harpellales also are reported; these are Graminella bulbosa, Pennella angustispora, Spartiella barbata, Stachylina euthena, St. grandispora, St. pedifer, St. penetralis, St. prolifica, St. robusta and Stipella vigilans. All are compared with related taxa and are illustrated with photographs. Finally a summary of the known Harpellales occurring in the Iberian territory is provided with data on their distribution and ecology.
Key words: gut fungi, insect larva, symbiosis, taxonomy, Zygomycota
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYPREVIOUSLY KNOWN SPECIESDISCUSSIONLITERATURE CITED |
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, Santamaria 1997, Santamaria and Girbal 1997, 1998, Valle 2004, 2006, Valle and Santamaria 2002a, b, 2004a, b, 2005) the present article encompasses and summarizes our knowledge of Harpellales from the Iberian Peninsula, a microcontinent with a physiographical, bioclimatic and phytogeographical diversity that allows the occurrence of both Mediterranean and Eurosiberian floristic and vegetation zones (Rivas-Martínez 1987). This area in the western Mediterranean basin, southern Europe, is influenced predominantly by the Mediterranean Sea, which borders the peninsula on the east and south, and by the cooler Atlantic Ocean on the west and north.
Harpellales are endosymbiotic filamentous fungi that develop within the gut of their immature arthropod hosts, mostly aquatic species of Diptera, stoneflies (Plecoptera), mayflies (Ephemeroptera), and more infrequently beetles (Coleoptera), caddisflies (Trichoptera) and Isopoda (Lichtwardt et al 1999b, 2001a, White 1999). In terms of insect diversity the Iberian Peninsula and Balearic Islands have listed ca. 155 species of Ephemeroptera (Alba-Tercedor and Jímez-Cuéllar 2003), ca. 140 Plecoptera (Tierno de Figueroa et al 2003) and ca. 1860 nematoceran Diptera (Carles-Tolrá and Hjorth-Andersen 2002). The relationship between these gut fungi and their hosts in most cases is considered to be commensalistic, whereas for some species of Smittium that have been cultured parasitic or mutualistic effects have been reported (Sweeney 1981a, b, McCreadie et al 2005).
All species reported in this article are in the order Harpellales, which include species with branched thalli comprising the family Legeriomycetaceae (Capnio-Capniomyces, Graminella, Legeriomyces, Pennella, Spartiella and Stipella) and the family containing members with unbranched thalli, the Harpellaceae (Stachylina).
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYPREVIOUSLY KNOWN SPECIESDISCUSSIONLITERATURE CITED |
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. The hosts were transported to the lab in a portable cooler with bagged ice. Insect guts were removed and cleaned of their contents under magnification with the aid of a steromicroscope. Trichomycetes attached to gut linings were placed on a slide in water, cover slipped and examined with phase contrast or interference contrast optics. Fungi on the slides were stained and preserved with lactophenol cotton-blue (LPCB) and deposited in the herbarium (BCB-Mycotheca, at the institutional address of the author). All type slides for new species are deposited at Farlow Herbarium (FH). Photographs were made from LPCB fixed slides. Insect vouchers were preserved in 75% alcohol. (TABLE I is a summary of known Iberian Harpellales and includes distribution ranges, host families and bibliographic source.) Harpellid species with a wide distribution and/or geographic domain are marked as "Cosmopolitan?" to denote the scant information on Harpellales in many countries.
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TAXONOMY |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYPREVIOUSLY KNOWN SPECIESDISCUSSIONLITERATURE CITED |
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Thalli sparsely ramified from the basal cell. Basal cell wider than the upper ones, showing a fine coating of secreted holdfast material (FIG. 1
). Trichospores 10.5–13 x 3 µm, ovoid-ellipsoidal, without a collar, carrying an undetermined number of wide petaloid appendages observable inside the corresponding generative cell (FIGS. 1, 2). Generative cells 4–8 x 2–3.5 µm, with 6–12 cells per fertile branch (FIGS. 1, 2). Zygospores 35–38 x 5–6 µm, type II, regularly biconical and developing directly from the conjugation tube or near it (FIGS. 4, 5). Zygosporophore 16–20 x 3–4.5(–5) µm, released with the zygospore as a collar once mature. In the hindgut of Nemouridae (Plecoptera) nymphs.
Etymology. – Latin, celatus = hidden, referring to the ecology of the species, buried within hyphae of another Trichomycete, Lancisporomyces vernalis Santam. in this case.
Specimens examined.. SPAIN. BARCELONA: Sant Llorenç Savall, Vall d’Horta stream, 31TDG21, prepared from Nemoura cinerea Retzius nymphs, 1-II-2001, SP-Tr0476 (HOLOTYPE: FH), BCB-Tr0477.
Commentary. –
The type species, C. stellatus S.W. Peterson & Lichtw., was described from hosts of the genus Allocapnia (Capniidae, Plecoptera), which are endemic in North America (Peterson and Lichtwardt 1983). Capniomyces celatus was noticed in a stonefly host from a different family, which is widely distributed in Europe. In the type locality the host was abundant and highly infested with Lancisporomyces vernalis Santam. (Santamaria 1997) (FIG. 1) but just two of the nymphs were infested with C. celatus. The size of this new species, usually obscured by the dense thalli of Lancisporomyces, made detection difficult within the gut contents.
Capniomyces celatus has generative cells arranged in long series (<12) at the ends of fertile branches (FIG. 2), making it readily distinguishable from C. stellatus with typically only three trichospores per branch based on examination of the Holotype (FH) MIS-1-104. This characteristic of the new species, together with the smaller trichospores and zygospores (trichospores of [10–]15[–19] x 4–6 µm and zygospores of [42–]52[–64] x 7–9 µm in C. stellatus [Peterson and Lichtwardt 1983]), makes C. celatus unique, even though it was impossible to determine the exact number of trichospore appendages (six in C. stellatus, Peterson and Lichtwardt [1983]). Appendages in the Spanish specimens were barely visible inside the generative cells but appeared to be thick, petaloid, and occupying nearly the entire cell. Although most zygospores typically were formed on a zygosporophore from the middle of a heterothallic conjugation tube (FIG. 4) one of the observed zygospores was apparently homothallic (FIG. 5). Another zygospore (FIG. 6) appeared to have a type IV attachment (see Moss et al 1975 for zygospore types), but the sexual spore was not mature. Apparent "Type IV" arrangements of the zygospore on the zygosporophore occasionally have been observed with other species that typically show different types of attachment (e.g. Legeriomyces) (LG Valle unpubl); this could be caused by a developmental abnormality that causes the type II zygospore to appear with a polar rather than an oblique attachment to the zygosporophore.
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Thallus 6–7.5 µm diam cum sparsim ramificanti principali axe. Basalis cellula cum simplici campanulato tenaculo. Trichosporae elongato-obpyriformes, 36–43 x 8.5–9.5 µm, cum appendicibus duabus, magis tenuibus ad extremum, prima elongata, altera brevi. Appendices helicte dispositae intra cellulam genitalem. Sine collari. Unaquaeque fertilis rama cum 2–5 genitalibus cellulis. Zygosporae 39–43 x 99.5 µm, asymetricae cum duobus extremis, quorum unum brevius et arcuatum, 9–12 µm, et alterum, 26–30 µm, longius et rectum. Liberae zygosporae cum collari, 11–13.5 x 5–6 µm. Zygosporophorum 12–13.5 x 5–6 µm. Ad cuticulam proctodaei nympharum Baetidae (Ephemeroptera) affixi.
Thalli sparsely ramified from the base, with an axial filament diameter of 6–7.5 µm. Basal cell slightly broadened (FIG. 10), with a conical secreted holdfast. Trichospores 36–43 x 8.5–9.5 µm, elongate-obpyriform without a collar but with two appendages differing in length (FIG. 8). Appendages wider at the proximal end, helically coiled inside the generative cell. Generative cells measuring 6–7.5 µm diam, variable in length, occurring in a series of 2–5 cells per fertile branch. Zygospores 39–43 x 9–9.5 µm, biconical, obliquely attached to the zygosporophore and markedly asymmetrical. The proximal end (9–12 µm) is curved toward the zygosporophore, whereas the longer end (26–30 µm) is straight (FIGS. 7, 9, 11). Zygosporophore 12–13.5 x 5–6 µm, with a dense cytoplasm that aggregates into a slender conical shape after staining with LPCB (FIGS. 6, 7, 11). The zygospore on release has a collar (11–13.5 x 5–6 µm) at its base (FIG. 7). In the hindgut of Baetidae (Ephemeroptera) larvae.
Etymology. – Latin, dolabrae = an agriculture digging tool (a sort of hoe), which resembles the zygospore in morphology.
Specimens examined.. SPAIN. GUADALAJARA: Valdesotos, Rio Jarama, 30TWL73, prepared from Baetis rhodani (Pictet) larvae, 19-IX-2001, BCB-Tr0985, SP-Tr0986 (HOLOTYPE: FH), BCB-Tr0987, BCB-Tr0991–Tr0993.
Commentary. –
The most interesting and characteristic feature of this species is the asymmetric zygospore shape, with the shorter end characteristically curved downward toward the zygosporophore (FIGS. 6, 7, 9). Also the aggregated cytoplasmic content of the fixed and stained zygosporophore and the larger trichospore diameter in L. dolabrae separate it from L. ramosus Pouzar, a species documented from Spain (Valle and Santamaria 2002a). The other species in the genus, L. rarus Lichtw. & M.C. Williams, also reported from Spain (Valle and Santamaria 2004b), has different thallus features, shorter trichospores as well as more typical, type II biconical zygospores (Williams and Lichtwardt 1993).
Stipella latispora L.G. Valle, sp. nov. FIGS. 12–15
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Thallus pinnately ramified, with a central axis 8–9.5 µm wide. Basal cell lobulate (FIG. 12) or simple (FIG. 14), coated with amorphous material. Small peg-like projections irregularly dispersed along the basal cell surface (FIG. 14 arrow). Trichospores 60–70 x 8.5–9 µm, ovoid-ellipsoidal and slightly curved, eccentrically attached to the generative cell, without a collar, 6(–7) petaloid appendages present (FIG. 13 arrow). Generative cells 3.5–4 µm diam, arranged in series with 1–4 cells per fertile branch (FIG. 12). Zygospores 89–92 x 13 µm, biconical, type I, formed homothallically from cells near conjugation tubes (FIG. 12, 15). Zygosporophore 30 x 11 µm, partially carried as a collar by the zygospore once released. In the hindgut of Simuliidae (Diptera) larvae.
Etymology. – Latin, lati = wide, spora = spore referring to the wide trichospores in the species.
Specimens examined.. SPAIN. MURCIA: Moratalla, Rio Beamor, 30SWH92, prepared from Simuliidae larvae, 13-V-2003, SP-Tr1761 (HOLOTYPE: FH), BCB-Tr1763. HUELVA: Arroyomolinos de León, Rio Montemayor, Sierra de Aracena, 29SQC21, prepared from Simuliidae larvae, 6-XI-2003, BCB-Tr1869–1870.
Commentary. –
This is the second species in the genus. The key characteristic is its large trichospores, consistently wider than those of the type species S. vigilans Léger & Gauthier (Léger and Gauthier 1932). General features of the thallus are similar for both species. The zygospores of S. latispora (FIG 12 arrow) are also larger and straighter than those of S. vigilans (FIG. 32). One of the more intriguing features is the presence of six (rarely seven) appendages on the trichospores (FIG. 13 arrow), whereas only 3–4 were described previously for S. vigilans (FIG. 33). The morphology of the basal cell is variable (FIGS. 12, 14) as in the type species (FIG. 34). The variability of appendage number and holdfast characteristics within S. vigilans had been reported by Manier (1963) and Moss (1970), but trichospores consistently are narrower in S. vigilans compared to S. latispora (FIGS. 12, 13, 15).
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PREVIOUSLY KNOWN SPECIES |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYPREVIOUSLY KNOWN SPECIESDISCUSSIONLITERATURE CITED |
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Specimens examined. – SPAIN. BARCELONA: Guardiola de Berguedà, Rio Grèixer, 31-V-2001. Cardona, Rio Cardener, 4-II-2002. GIRONA: Meranges, Foguerade stream,, 9-VIII-2000. Cantallops, Collpregon stream, 14-VI-2001. GUA-DALAJARA: Valdesotos, Rio Jarama, 19-IX-2001. HUESCA: Salinas de Sin, Rio Cinqueta, 10-X-2000. LLEIDA: La Coma, Fonts del Cardener, 30-VIII-2000. Alins, Areu, Aixeus stream (Noguera Rio Vallferrera), 23-VI-2001. SEGOVIA: Vegas de Matute, Rio Moros, 24-IX-2001. TERUEL: Beseit, El Parrissal, Rio Matarranya, 24-III-2001. VIZCAYA: Guriezo, Rio Agüera, 29-V-2002. Mendata, Rio Golazo, 7-X-2002. All specimens prepared from nymphs of B. alpinus Pictet, B. rhodani and Baetis sp.
This species was described from France in the hindguts of Baetis sp. (Léger and Gauthier 1937) and was found in the same country by Manier (1962) in Baetis rhodani (Pictet), a common and widespread Baetidae. This paper represents the first record of this species in the Iberian Peninsula, where it shows the same ecology as Legeriomyces ramosus. Both species often were found in the same hindgut. The species is characterized by the numerous small trichospores (FIG. 18), the formation of bulbous basal cells (FIGS. 16, 17) and vegetative propagules (Léger and Gauthier 1937), observed in collections from Iberia.
Pennella angustispora Lichtw., 1972. FIGS. 19–21
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This species is rare in the study area, recorded from a single locality, although the hosts are common. The typical cylindrical-clavate trichospores (FIGS. 19–21) are distinctive, and the Iberian specimens (50–73 x 2.5–3.5 µm) share the same characteristics as specimens from USA (Lichtwardt 1972) and Japan (Dang 1979, Sato 2001). Nelder et al (2005) reported the species in endemic Simuliidae from Armenia (Asia). The species has not been reported before from Europe.
Spartiella barbata Tuzet & Manier ex Manier, 1968 FIGS. 22–30
Specimens examined. – SPAIN. BARCELONA: Vacarisses, Senana stream, 6-VI-2001. BILBAO: Guriezo, Rio Agüera, 29-V-2002. GIRONA: Santa Pau, Can Patxet, Bosquet stream/Sant Martí stream, 5-IX-2000. Sant Jaume de Llierca, Rio Llierca/Castellà stream, 5-IX-2000. Vall de Bianya, Rio Vall d’en Bac, 5-IX-2000. HUESCA: Loporzano, Rio Isuela, larvae, 19-IX-2000. Sesa, Rio Guatizalema, 19-IX-2000. Adahuesca, Río Vero, 20-IX-2000. Santa Eulalia la Menor, Rio Flumen, 20-IX-2000. Salinas del Sin, Rio Cinqueta, 10-X-2000. LLEIDA: Guixers, La Casa Nova de Valls, Rio Aigua de Vall, 30-VIII-2000; Rio Aigua d’Ora, 30-VIII-2000. MADRID: Valdesotos, Rio Jarama, 19-IX-2001. Pinilla del Valle, Rio Lozoya, 3-X-2001. El Paular, Umbría stream, 3-X-2001. TERUEL: Beseit, Rio Matarranya, 24-III-2001. All specimens prepared from nymphs of B. alpinus, B. rhodani and Baetis sp.
This species was described from France (Tuzet and Manier 1950) and is similar to its American congener S. animae, differing only in trichospore size (Lichtwardt 1997). Spartiella barbata is easily identifiable by its lobulate basal cell (FIG. 22) and typical obpyriform trichospores (20–26 x 6.5–8.5 µm) with one appendage that remains tightly coiled just after release (FIG. 26) but eventually uncoils into a long, fine appendage (FIG. 25). Zygospores (25.5–34 x 6–7.5 µm) were present (FIGS. 23, 24). The species frequently appeared together with Legeriomyces ramosus in Baetidae hindguts. Morphological characters are congruent with the original description, except for presence of smaller trichospores in some localities. An interesting feature concerning the method of trichospore extrusion is described for the first time from specimens on microscope slide BCB-Tr0315 (from Huesca). The sporangium content is released through a hyaline tube formed at the apex of the trichospore (FIGS. 27–30). This channel is formed by a progressive elongation of the apical internal wall, which can be detected initially by an anomalous extension of the trichospore at its apex (FIG. 27). The extruded sporangiospore is surrounded by a thin hyaline wall. A similar trichospore extrusion method was reported from cultured Smittium culisetae Lichtw., described as a sleeve-like membrane between the trichospore wall and sporangiospore (Horn 1989). In the case of S. barbata the structure is more like a cylindrical tube with a uniform diameter. Another observation of an extrusion process is that of Ejectosporus spica (S.W. Peterson & Lichtw.) Strongman, where the sporangiospore content of the vegetative cells has a lunate shape (Lichtwardt et al 1991, Strongman 2005).
Stipella vigilans Léger & Gauthier, 1932 FIGS. 31–34
Specimens examined. – SPAIN. BALEARIC ISLANDS (MAJORCA): Santa Maria del Camí, Coanegre stream, 27-V-2003. Sóller, Biniaraix, l’Ofre stream, 29-V-2003. Valldemossa, Valldemossa stream, 30-V-2003. BARCELONA: Mura, les Nespres stream, 6-II-2001. Sant Llorenç Savall, Vall d’Horta stream, 1-II-2001. Santa Maria de Corcó, Paganes stream, 19-II-2001; El Freu stream, 19-II-2001; Sant Julià de Cabrera, Sant Julià stream, 19-II-2001. CUENCA: Tragacete, Rio Júcar, 1-X-2001. GIRONA: Espinelves, Mas Joan, Major stream, 10-VII-2000. Setcases, Obaga de Carboners, 12-IX-2000. JAÉN: Vadillo-Castril, Rio Guadalquivir, 12-VII-2001. Tranco de Beas, Rio Guadalquivir, 12-VII-2001. LLEIDA: Espot, Pla de Fontinals, 21-VI-2001. MADRID: Pinilla del Valle, Rio Lozoya, 3-X-2001. VIZCAYA: Trebueso, Rio Agüera, 29-V-2002. All species prepared from Simuliidae larvae.
This species was found in diverse localities on the Iberian Peninsula and the Balearic Islands (Majorca), where it frequently was collected and grew densely within its hosts. The specimens examined share thallial and spore characteristics with the French type specimens. The cylindrical trichospores (FIGS. 31, 33), (41–58.5 x 2.5–4 µm), with 2–4 fine appendages, are typical for the species. The zygospores observed generally were smaller (62–82 x 12.5–16 µm) (FIG. 32) than those reported for the type (80–105 x 15–18 µm).
Stachylina euthena Manier & F. Coste, 1971 FIGS. 35–36
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Harpellaceae species have been described from France, in diverse genera of Chironomidae (Manier and Coste 1971). After the initial description S. euthena was not reported again until this study in another southern European locality, the Iberian Peninsula. Stachylina euthena is similar to S. grandispora Lichtw. in its general features, the latter having larger trichospores and a shorter collar (Lichtwardt 1984). The Iberian specimens have trichospores measuring 27–39 x 6.5–8 µm with a collar 2 µm long, matching the original description well. Nonetheless there is some variability in trichospore shape in the Iberian specimens, which ranges from the typical fusiform with a medial swelling to clearly ellipsoidal ones (FIGS. 35, 36). The basal cell of the thallus has a small discoid holdfast (FIG. 35). However overall the specimens from the two localities in Spain do not show significant morphological variation.
Stachylina grandispora Lichtw., 1972 FIGS. 37, 38
Specimens examined. – SPAIN. BARCELONA: L’Estany, L’Estany stream, prepared from Chironomidae Diamesiinae larvae, 19-XII-2000. Navàs, Palà de Torroella, Rio Cardener, prepared from Chironomidae Diamesiinae larvae. GIRONA: Cruïlles, Monells i Sant Sadurní de l’Heura, Cantagalls stream, prepared from Chironomidae larvae, 13-XII-2000.
This is one of the more common species within the genus, with a worldwide distribution (United Kingdom, Australia, Hawaii, New Zealand, Sweden and USA). Some of the Iberian specimens had trichospores (FIGS. 37, 38) slightly narrower ([36–]40–68 x [5.5–]6–8.5 µm) than those of the original description (Lichtwardt 1972), but variability in this character has been reported before (Lichtwardt et al 2001a).
Stachylina pedifer Lichtw. & M.C. Williams, 1983 FIGS. 39–41
Specimens examined. – SPAIN. BARCELONA: Fígols, Peguera, Fontana Coix, prepared from Chironomidae, 31-V-2002. GIRONA: Viladrau, Riera Major stream, Fontana Ferro, prepared from Eukierffiella sp. larvae, 23-X-2002.
This species shares characteristics with S. penetralis Lichtw., such as the basal cell penetrating the peritrophic matrix of the host (FIGS. 39–41) and variability in trichospore shape (FIG. 39), which also is variable for S. penetralis (Lichtwardt 1984, Lichtwardt et al 2001a) and can make identification difficult. The Iberian specimens show the typical foot-like basal cell of S. pedifer, which slightly penetrates the peritrophic matrix of the midgut (FIG. 40). The number of generative cells per thallus is 2–8, according to Lichtwardt and Williams (1983), but up to 10 trichospores per thallus were observed, although normally there were 4–8 spores. Trichospores measured 25–33 x 7–9 µm and fit the species description well.
Stachylina penetralis Lichtw., 1984 FIG. 42
Specimens examined. – SPAIN. BARCELONA: Moià, la Fàbrega stream, prepared from Chironomidae Diamesini larvae, 13-V-2002. Avià, Clarà stream, 2-IV-2001. Cercs, Rio Llobregat, 2-IV-2002. GIRONA: Queralbs, Núria, Coma d’Eina stream, 25-VIII-2000. Boadella d’Empordà, Rio Muga, 4-VI-2001. Viladrau, Riera Major stream, Fontana Ferro, 23-I-2002. All specimens prepared from Chironomidae larvae, mostly Diamesinae.
Stachylina penetralis has been described from insects collected in France, Sweden and Japan (Lichtwardt 1984) in diverse Chironomidae species. This species has a globose basal cell that penetrates the peritrophic matrix (FIG. 42). Occasionally, if the view of the basal cell is not lateral but frontal or dorsal, and the specimen is not mature, it is possible to misidentify this species as S. minuta Gauthier ex Lichtw. or S. pedifer. The Iberian specimens showed no remarkable differences from the published description of this species, with trichospores measuring 33–42(–46) x (7–)8–11 µm.
Stachylina prolifica Lichtw., Kobayasi & Indo, 1987 FIGS. 43–45
Specimens examined. – SPAIN. BARCELONA: Fogars de Montclús; Sta. Fe del Montseny stream, near Fontana Passavets, 25-X-2001. Gualba de dalt, Gualba stream, 7-IX-2001. GIRONA: Agullana, la Guilla torrent, 14-IV-2001. VIZCAYA: Turcíos, Rio Agüera, 29-V-2002. All specimens prepared from Chironomidae Diamesiinae and Orthocladiinae larvae.
This represents the first report of this species outside the type locality in Japan where it was described from bloodworm (Chironomus sp.) larvae (Lichtwardt et al 1987). The thalli of this species show great variability in length, and can produce 4–50 generative cells each. Similar variability was observed with the Iberian specimens but most of the thalli had about 20 generative cells (range 8–45). Trichospores were long and narrow (23.5–38 x 4–6 µm) and were produced profusely on the thallus (FIG. 43), borne on numerous, small generative cells (7–14 x 7–12 µm). Also the specimens had a narrow peg-like basal cell (FIGS. 43–45) which is diagnostic for the species.
Stachylina robusta Lichtw. & M.C. Williams, 1999 FIGS. 46–48
Specimens examined. – SPAIN. BARCELONA: Gualba de Dalt, Gualba stream, prepared from Chironomidae Orthocladiinae larvae, 7-XI-2001. VIZCAYA: Trucíos (Turtzioz), Rio Agüera, prepared from Chironomidae Orthocladinae larvae, 29-V-2002.
These collections are the first for this species outside North America, where it was reported from the USA by Lichtwardt and Williams (1999) and Canada by Lichtwardt et al (2001b). This is a species easily identified by the relatively thick thallus, the large number of generative cells and collarless trichospores (FIGS. 46–48). In Spanish collections it was observed occasionally that the generative cell remained attached as an ephemeral collar to the trichospore after release. The Iberian specimens had a thallus diameter of 12–14 µm and elongate-ellipsoid trichospores, 29–35 x 7.5–8.5 µm. Another species with similar features is S. jujuyensis Mazzuchelli, Lopez-Lastra & Lichtw. described from Argentina, which has thalli 10 µm thick and trichospores in the same size range (Lichtwardt et al 2000).
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYPREVIOUSLY KNOWN SPECIESDISCUSSIONLITERATURE CITED |
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). Most diversity is recorded within the genera Smittium and Stachylina, in accordance to most previous data worldwide (Lichtwardt et al 2001a). Within the Iberian taxa and according to current information, the proportion of dipteran-associated Harpellales confined in the Palearctic regions is 58%. The Iberian harpellid species living within Plecopterans are 100% Palearctic, while Ephemeropteran-associated species are 80% Palearctic. The remaining Harpellales for these data correspond to widely distributed or Holarctic species (see TABLE I, also for bibliographic information). These results are mainly in agreement with other studies, where a high percentage of Dipteran Harpellales appear not to be restricted geographically in spite of their host endemicity (Nelder et al 2004, 2005) or isolation (Lichtwardt et al 2001a, Valle and Santamaria 2004b). In Spain none of the species reported among Stachylina, Harpella, Harpellomyces or Genistellospora were new, and 60% of the Smittium species currently are known from other places (TABLE I). The capacity of adult females of Simuliidae and Chironomidae to carry harpellid diaspores called ovarian cysts or chlamydospores (Labeyrie et al 1996, Moss and Descals 1986, Yeboah et al 1984) might aid the dispersion of those cosmopolitan Smittium species, which also have a high adaptive plasticity among diverse hosts (Nelder et al 2004). In the case of Harpellales living in the guts of Plecopteran and Ephemeropteran hosts, the higher percentage of endemicity (Peninsular or Palearctic) is in agreement with the possible incapacity of adult hosts to transport fungal diaspores inside their bodies. This could explain why species such as Capniomyces celatus or Legeriomyces dolabrae have a restricted distribution. The locus classicus of Capniomyces celatus is in a Mediterranean forest of evergreen pine and oak that was destroyed by fire after the collections were obtained. In subsequent surveys stonefly hosts were not found, as a result of the ecosystem devastation. This event presents the opportunity to study the resilience of trichomycete species subjected to random, severe disturbances, which are frequent in Mediterranean zones, and might have caused on more than one occasion the fragmentation and destruction of ecosystems and arthropod populations. The new species Legeriomyces dolabrae shares some characteristics with L. ramosus, suggesting a close relationship. In fact variation in L. ramosus zygospores, including abnormalities in the position and shape of these sexual structures, mixed with normal zygospores, also have been noted (unpubl). Even so the asymmetric zygospores of L. dolabrae are a consistent feature in these collections and none of the more typically biconical zygospores were observed.
Stipella latispora was found in southern localities of the Iberian Peninsula, at the middle course of permanent streams. This new species might be more widely dispersed in southern Spain, although it likely is more rare than S. vigilans. Variability in trichospore features are well know in this genus; nevertheless diagnostic characters are consistent in all specimens examined and allow for easy separation of S. latispora from the more common S. vigilans. The number of appendages present on trichospores has been used widely to separate genera within the Harpellales, but Stipella with the new species S. latispora include species with different numbers of appendages. Other genera with species showing variable number of appendages are Bojamyces Longcore (Valle and Santamaria 2004b), Harpella Léger & Duboscq (1929), Pennella Manier (1968), Simuliomyces Lichtw. (1972) and Plecopteromyces Lichtw., Ferrington & López Lastra (Lichtwardt et al 1999a). Stipella vigilans is restricted to Europe and western Asia (see Table I, also for bibliographic information). It is not clear whether this more restricted distribution is caused by lower dispersive ability compared to other species occupying the same niche in the gut of Simuliidae (i.e. Smittium, Genistellospora). The data concerning Majorcan Harpellales provide information for further studies on insular populations to help elucidate whether their presence on this island is the result of relictual populations, colonization or both. Concerning this and other aspects of the understudied Trichomycetes, the more we come to understand their biology, the more they challenge our understanding of them.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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1 Corresponding author. E-mail: laia.guardia{at}uab.es
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LITERATURE CITED |
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