Simulium (Nevermannia) berchtesgadense
Creators: name: Seitz, Gunther
name: Adler, Peter H.
name: Forster, Mira
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Simuliidae
Simulium
Simulium berchtesgadense

description: Simulium (Nevermannia) berchtesgadense nov. spec.
(Figs.1–14)
Holotype. Male with associated pupal exuviae in ethanol; abdominal tip with prepared genitalia parts in separate microvial with glycerin, one hind leg with tarsi of forelegs mounted in Euparal. Germany, Bischofswiesen, near Berchtesgaden, spring to Weißbach, orographically from the right side, 770 m elevation, collected 27 April, emerged 30 April 2013, leg. Gunther Seitz (deposited in the Bavarian State Collection of Zoology (ZSM), Munich, Germany).
Paratypes. Same location and date as holotype: Female with associated pupal exuviae in ethanol, head, abdominal tip and hind leg in separate microvial with glycerin (ZSM); emerged 30 April 2013, leg. Gunther Seitz. 1 male and 2 females with their exuviae, 5 pupae, 20 larvae (ZSM); 2 pupae, 7 male and 7 female larvae in Carnoy’s fixative (transferred to ethanol after chromosome extraction; Clemson University Arthropod Collection (CUAC), Clemson, South Carolina, USA); 1 male and 1 female with their exuviae, 7 pupae, 2 pupal exuviae, 17 larvae, in ethanol (Collection G. Seitz). The material is listed in Table 1.
Etymology. The species name is from the denomination of UNESCO biosphere reserve Berchtesgaden in the northern limestone Alps of southeastern Germany.
Male. Length of body 4.7 mm, wing length 3.8 mm. Scutum black, thoracic hair golden. Radius with hair dorsobasally. Stem vein and basicosta with long brown hair. Mesepimeral tuft bright brown. Basal fringe and abdominal hair brown, paler at tips. Legs brown, base and tip of femora and tibiae darker; recumbent pilosity golden yellow, shining. Hind leg with basitarsus nearly 4 times longer than wide at widest point (Fig. 1); calcipala about ½ width of apex of basitarsus; pedisculus weakly developed. Male genitalia: Ventral side of gonocoxite with long brown hairs, dorsally hairs shorter. Gonostylus shorter than coxite, nearly parallel sided; distally with medially directed, subtriangular flange bearing one apical spinule (Fig. 2). Ventral plate (Fig. 3) bent in profile, in ventral view with body rectangular, anterior edge slightly convex, posterior edge concave, posterolaterally rounded with crenulations; lip with hairs originating from verrucous excrescences; basal arms slender, slightly longer than length of body of ventral plate, and with apical half of each arm slightly directed medially. Parameres each with one strong spine; dorsal plate with its basal flange mushroom-shaped; median sclerite elongated, slender, apically widely bifurcated (Fig. 4).
Female. Length of body 4.8 mm, wing length 4.5 mm. Scutum and humeral angles dark brown; scutellum light brown; thoracic hair light-coloured. Postnotum light brown with few light-coloured hairs. Frons at narrowest width nearly 1/8 width of head; frons and clypeus with light-coloured hair. Mandibles with about 41 serrations (11 outer and 30 inner, the last of each side weakly defined); laciniae with 25–27 retrorse teeth. Palpomere V 1.6 times longer than palpomere III. Sensory vesicle in lateral view elliptical, nearly ½ as long as palpomere III. Stem vein and basicosta with golden hair. Basal fringe and mesepimeral tuft golden. Precoxal bridge complete. Legs light brown, darker on tarsi and apices of femora and tibiae; hair predominantly brown; calcipala about ½ width of apex of basitarsus; pedisulcus weakly developed. Claws each with basal, thumblike lobe. Terminalia (Fig. 5): Cercus strongly haired on both sides. Anal lobe sclerotized at edges, medioventrally bulging; beset only with few hairs on both sides. Hypogynial valves almost transparent, divergent basally, touching distally (only approximated before dissection of abdomen). Few short, small hairs present on basal half of each valve, otherwise unhaired. Cercus in lateral view subtriangular with rounded corners, broader than long; anal lobe ventrad conically elongated, covered with few hairs increasing in size and strength at caudal side (Fig. 6). Genital fork (Fig. 7) with long stem well pigmented; stem 1.4 times longer than arms. Arms distinctly divergent, extended posteriorly beyond lateral plates, enclosing wide U-shaped space. Lateral plates each with dark brown pigmented cuticle and short, blunt, anteriorly directed apodeme (Fig. 6). Spermatheca (Fig. 7) slightly longer than broad, about ½ as long as stem of genital fork, with polygonal surface pattern; unpigmented area present at junction with spermathecal duct.
Pupa and cocoon. Body length (without gill) up to 4.9 mm. Gill of four closely spaced filaments with their tips directed downwards, shorter than pupa; lower pair of filaments branched in vertical plane, upper pair of filaments branched in more diagonal plane; filaments acute-angle branched, diverging from common basal trunk about 2.5–3.0 times longer than wide. Lower arm longer than, or as long as, upper one, upper arm thicker than lower; filaments with transverse furrows (Fig. 8). Head plate and anterior thoracic dorsum densely covered with circular microtubercles (up to 7.5 µm), the latter covered with few microgranules (Fig. 9); thoracic trichomes unbranched, up to 300 µm long. Upper part of frontoclypeal shield with 2 short setae per side, 1 short branched trichome medially on lower part per side (often broken). Terminal spines small, pointed. Cocoon slightly longer than pupa, slipper shaped, with strongly thickened rim, particularly medially, often with several small single strands protruding but without real anterodorsal projection, loosely woven so that small particles visible in holes having
Larva. Length of last instar up to 8.7 mm. Ground colour of body white-yellow, front of body with more or less distinctly pigmented brownish areas. Head light brown with washed-out positive brown head spots, frontoclypeal apotome slightly paler than postgenae; posteromedial head spot equal-sided triangular or long oval (Fig. 11). Postgenal cleft up to 120 µm long, arc-shaped or trapezoidal, extended ¼ distance to hypostomal groove, lateral edge of posterior tentorial pits bright comma shaped (Fig. 12); subesophageal ganglion unpigmented. Hypostoma with usual number of apical teeth: Median tooth of same length or slightly longer than 2 strong lateral teeth; in between 3 sublateral small teeth on each side (Fig. 13). Paralateral teeth composed of 2 conspicuous teeth; 6 sublateral hypostomal setae arranged one behind other per side, most distally bifid, sixth seta shorter without bifurcation. Antenna longer than stem of labral fan, transparent with articles 1 and 2 brownish, up to 0.65 mm long, proportion of articles, proximal to dorsal (excluding apical sensillum), 1.4:1.6:1.0. Mandible with normally developed apical and preapical teeth, followed by 8 spinous comb teeth; inner preapical ridge of mandible with 1 main tooth followed by 6 small teeth (Fig. 14). Labral fans each with 28–34 primary rays (median: 31 rays, N=9 mature larvae). Abdomen with conical abdominal ventral tubercles on each side of last segment. Anal sclerite Xshaped with sclerotized areas alongside arms and between two halves. Anterodorsal arms shorter than posterodorsal arms. Cuticle beside sclerite with numerous hairs, up to 33 µm long, no rectal scales. Rarely extruded rectal papillae with 3 compound lobes, each with about 12 lobules. Posterior circlet with about 93 rows of about 11 hooks per row.
Chromosomes. The new species was represented by chromosome preparations from 7 female and 7 male larvae (Table 2). A chromocenter, ectopic pairing, and supernumerary (B) chromosomes were lacking. Chromosome arms IS, IIS, and IIL had the standard banding sequence of Brockhouse (1985) for the Simulium vernum group. Larvae were fixed for IL-2, which is widespread in the Palearctic S. vernum group, and IIIP-1, IIIS- 3, and IIIL-2 (t sequence of Hunter 1987). The pericentric IIIP-1 inversion and IIIL-2 are shared with a number of European species in the S. vernum group, whereas IIIS-3 is shared with a more restricted group of species, including S. cryophilum cytoform 'A' and S. urbanum (Adler & Seitz 2014). One autosomal polymorphism, a unique heteroband (IL Hb-36A3), was found heterozygously in a single male larva. The Y chromosome was associated with a slight unpairing of the centromere region of chromosome III (CIII) into the base of IIIL. Thus, sex chromosomes were X0Y1. Based on our small sample, S. berchtesgadense is chromosomally most similar to S. cryophilum cytoform 'A', but differs by being fixed for IIIL-2 (t sequence) and having a slightly differentiated Y chromosome.
a Italicized rearrangements indicate they are fixed.
Diagnosis and taxonomic remarks. The different life stages in the Simulium (Nevermannia) vernum group often differ little, especially among the Alpine species (Clergue-Gazeau 1991, Rivosecchi 1978). Our comparisons are based on the descriptions in the relevant literature and on our own specimens of different species. Because of the chromosomal similarity, we highlight the differences from Simulium (N.) cryophilum, but above all there is one character which characterises all life stages: In addition to Simulium (N.) costatum Friederichs, our new species is one of the largest species of the S. vernum group in Europe (Rubtsov 1962).
Males can be distinguished from those of other European members of the S. vernum group by the combination of the parallel-sided gonostylus, somewhat shorter than the gonocoxite, as well as by the rectangular ventral plate with apices of the basal arms slightly directed inward and with crenulations posterolaterally. In addition, the mushroom-shaped dorsal plate seems unique among the known Alpine species of the S. vernum group. It resembles that of Simulium (N.) cryophilum (Rubtsov) (Clergue-Gazeau 1991: fig. 110 and Rivosecchi 1978: fig. 67, 9) but is not divided in two equal parts. The resemblance to the latter species also results from the existence of the excrescences on the ventral plate (Rivosecchi 1978, fig. 68, 7) but these are more numerous in our species. Apart from that character, both taxa differ in the crenulations along the posterolateral edges of the ventral plate. The length/width ratio of the hind leg basitarsus is greater in our species than in Simulium (N.) cryophilum (Rivosecchi 1978, fig. 104, 13).
The most striking character is the triangular cercus with its rounded corners and the ventrad conically elongated anal lobe, which resemble those of Simulium (N.) costatum. All other Alpine species in question have rounded or rectangular, rounded cerci (Knoz 1965). Compared to these species, the number of the mandibular teeth is conspicuously greater (Rivosecchi 1978); only Simulium (N.) carthusiense Grenier & Dorier and Simulium (N.) bavaricum Seitz & Adler have approximately the same number as in our species.
In the size of the pupa and the branching of the filaments, our species resembles Simulium (N.) costatum in Central Europe. But in contrast, the cocoon is loosely woven so that small particles are visible in the holes of the weave. Furthermore, the lower, thinner petiole of filaments is generally longer than the thicker upper one and the tips of the four filaments of the gill are directed downward, compared to the rigid filaments of Simulium (N.) costatum being forward and parallel sided; the thoracic dorsum of our species bears more and larger microturbercles, which in addition are covered with few microgranules.
In comparison with other species of the Simulium (N.) vernum group, the size of the postgenal cleft is the only character that could probably be mistaken for that of Simulium (N.) vernum Macquart. Otherwise, the bright comma-shaped lateral edge of the posterior tentorial pits and the hypostoma with its two strong lateral teeth followed by conspicuous paralateral teeth are distinct characters.
Larvae of Simulium (Nevermannia) berchtesgadense are fixed for IIIL-2 and lack the common polymorphisms of S. cryophilum ‘A’, such as IIIL-19’.1’.
Distribution and bionomics. Simulium (Nevermannia) berchtesgadense n. sp. is known only from the locus typicus at 770 m a.s.l, a small slow-flowing rheocrene with a discharge of less than 1 l/s, which breaks out of a north-facing limestone slope and flows into a mountain stream after several tens of meters. Because the immediate surroundings are largely free of higher vegetation, the exposure of light is determined by the surrounding mountains. In addition to our new species, the spring harbours a typical hypocrenous association with Simulium (Rubzovia) lamachi Doby & David, to date the only known finding in Germany (Seitz & Forster 2004, displaying the habitat with fig. 2), as well as Simulium (N.) beltukovae (Rubtsov), Simulium (N.) brevidens (Rubtsov), and Simulium (N.) cryophilum (Rubtsov). Larvae and pupae live in a thin water film on fallen leaves, branches, and small stones.
The first finding of this species (one pupa) dates to April 2003 but because the spring was only sporadically investigated in summertime in the following years, no additional specimens were found until springtime 2012. In this year, we found one larva and some pupae in springtime, as well as immature larvae in autumn, which underlines the possibility that Simulium (N.) berchtesgadense is univoltine with a diapause in summer.
Among 14 chromosomally prepared larvae, three female larvae and one male larva were infected with mermithid nematodes, one female larva had an unidentified microsporidium, and one male was infected with the fungus Coelomycidium simulii Debaisieux.
The feeding habits of the females are unknown, but the fully toothed mouthparts and basal, thumblike lobe of the tarsal claws suggest that they are ornithophilic. The discovery of this new taxon increases the number of species on the checklist of German black flies to 55 (cf. Seitz et al. 2013).
description: Published as part of Seitz, Gunther, Adler, Peter H. & Forster, Mira, 2015, A new species, Simulium (Nevermannia) berchtesgadense (Diptera: Simuliidae), and its chromosomes, from the Alps of southeastern Germany, pp. 248-262 in Zootaxa 3937 (2) on pages 249-258, DOI: 10.11646/zootaxa.3937.2.2, http://zenodo.org/record/237370