Thiasophila szujeckii Zagaja & Staniec

Zagaja, Mirosław & Staniec, Bernard, 2015, Thiasophila szujeckii sp. n. (Coleoptera, Staphylinidae, Aleocharinae) — a cryptic species associated with Formica truncorum in Poland, Zootaxa 3955 (3), pp. 417-426 : 419-424

Thiasophila szujeckii Zagaja & Staniec , sp. n.

Type locality. South-eastern Poland, the Sandomierska Basin, Wola Zarczycka near Leżajsk, pine forest (50º18’12.72”N, 22º16’14.74”E, UTM–EA87) ( Fig. 31, 31 A).

Type series. Holotype (male): Poland, Wola Zarczycka, in the area of the Leżajsk Forest Division, the Sandomierska Basin (SE Poland) (50º18’12.72”N, 22º16’14.74”E, UTM–EA87), 29 VII 2014, pine forest, in the nest mound of Formica truncorum , by sifting the nest material (the collection of the Department of Zoology of the Mariae Curie-Sklodowska University of Lublin). Paratypes (7 females, 4 males): same data as holotype (2 females), same data as holotype but collected from 1 V to 10 X 2010 (5 females, 4 males) by sifting a mound of nest, all collected by M. Zagaja (the collection of the Department of Zoology of the Mariae Curie-Sklodowska University of Lublin).

Description. Body ( Figs 1, 2 ) large, length 3.90–4.21 mm. Dorsal surface of head, pronotum and elytra mostly shagreened but slightly glossy. Head black, 1.0–1.2 as wide as long; surface finely, densely punctured, reticulated ( Fig. 2 A), but clypeus and frons weakly punctured, clypeus mildly rounded apically. Ligula robust widening gradually to apical part ( Fig. 5 ). Antennae rather slender as long as head and pronotum combined, reddish brown, segments I–III and XI distinctly lighter, segment I slightly widened apically, segment II and III almost equal in length, segment II slightly and segment III distinctly widened apically, both almost twice as long as wide, length to width relation segments IV–XI slightly different depending on sex ( Figs. 3, 4 ; see description below). Pronotum slightly convex, widest near middle, 1.6 times as wide as long, dark brown, but paler around posterolateral corners and lateral margins; anterior margin truncate; lateral margin gently rounded, subparallel-sided in posterior part; posterolateral corners visible, slightly rounded, posterior margin rounded; surface shagreened, reticulated ( Fig. 2 B). Elytra slightly widened posteriorly, posterior margin deeply notched near posterolateral corners ( Fig. 2 D); reddish brown, near scutellum, anterior and lateral margin to posterolateral corners dark brown; surface shagreened, reticulated ( Fig. 2 C). Legs reddish brown, tarsi somewhat paler. Abdominal segments III–IV or III–V reddish brown, segments VI–VII (sometimes V) dark brown with lighter posterior margin, apical segments yellowish brown; tergites glossy but reticulated and densely with setiferous punctures that become sparser towards apical segments ( Fig. 2 E).

FIGURES 11–28. T. szujeckii sp. n. (11, 12, 12A, 15, 17, 19–23), T. angulata (13, 14, 16, 18, 24–28). Aedeagus in ventral view (11, 13) and lateral view (12, 14); apex of apical lobe of aedeagus in ventral view (15, 16); apex of apical lobe of parameres in ventral view (17, 18); spermathecae (19–28).

Male ( Fig. 1 ). Antennae more slender than of female ( Fig. 3 ), length to width ratio of segments: IV to V–1.1:1, VI–1:1, VII to X–1:1.1, XI–2.6:1, respectively. Sternite VIII broadly rounded apically ( Fig. 7 ). Tergite VIII with posterior margin slightly emarginated medially, distinctly notched near lateral corners ( Fig. 9 ). Median lobe of aedeagus with sides in the greater part subparallel in ventral view (Fig. 11); apical lobe narrow in lateral view, flagellum short (Figs 12, 12A), widely rounded apically in ventral view (Fig. 15); apical lobe of paramere curved inside, slightly and gradually tapering to the apex, widely rounded apically, with basal setae about 0.8 times as long as apical lobe (Fig. 17).

Female ( Fig. 2 ). Body somewhat more robust than that of male. Antennae ( Fig. 4 ), length to width ratio of segments: IV–1.1:1, V–1:1.1, VI–1:1.2, VII to X–1:1.3, XI–2.3:1, respectively. Sternite VIII broadly rounded apically ( Fig. 8 ). Tergite VIII with posterior margin truncate medially ( Fig. 10 ). Spermatheca (Figs 19–23): apical part large, cylindrical; basal part with clearly visible dilatation near middle, curved inside about at 90o.

Comparative notes. Morphology. The new species in size, body shaped, structure of antennae is closely similar to T. angulata , but in structure of genitalia and coloration to T. lohsei ( Zerche 1987) . The unique characters of T. szujeckii sp. n. are the following: spermatheca with dilatation on basal part, apical part of parameres slightly, gradually tapering to apex, median lob of aedeagus in the greater part subparallel-sided, ligula widening gradually to the apical part. The new species is also distinguished from the other known, from the Palearctic region, Thiasophila species by its large size ( Zerche 1987; Maruyama & Zerche 2014). In this respect, the distinctiveness of T. szujeckii from most similar in size T. angulata is illustrated in Fig. 29 . The smaller group was formed by the larger specimens of the new species, which were collected exclusively in F. truncorum nest mounds. The bigger group consisted of the smaller individuals of T. angulata associated with F. ruf a and F. polyctena . Characteristics of adults which differentiate the three above-mentioned species are listed in Table 2 .

Phylogenetic analysis. The analysis of the partial COII sequence of T. angulata and T. szujeckii sp. n. found in four ant species of the Formica genus, exhibited the existence of four haplotypes (H1–4). Haplotypes H1, H2, H3 concern T. angulata , whereas, H4 is a haplotype of the new species. Genetic distances between obtained haplotypes varied from 0.002 between haplotypes H1, H2, H3 to 0.012 between H3 and H4, indicating a 1.2% difference between the sequence of these haplotypes ( Table 3 ). Minor differences in the COII gene sequence, less than 1%, were also observed between two species of butterflies; Ostrinia latipennis and O. ovalipennis ( Ohno et al. 2006) . Cognato (2006) comparing the differences between the sequence of mitochondirial and nuclear DNA markers of sixty two species of insects, determined the interspecies difference in the sequence of these markers in the range between 0.04 and 26.0%. Based on the obtained sequence (alignment) of the COII gene fragment a polygenetic tree was constructed using the ML method ( Fig. 30 ). Two major mtDNA clades were retrieved; first, the H4 haplotype, belonging to the T. szujeckii sp. n., the second to the other three haplotypes (H1–3) representing T. angulata . The branch grouping of these two evolutionary lines is supported by a high bootstrap ratio of 99. The typology of the polygenetic tree, constructed on the basis of the COII gene sequence, supports the existence of two separate species in the test material.

Supplement to the key. In order to include T. szujeckii sp. n. in the key to the Palearctic Thiasophila species except Japan ( Zerche 1987)§, the following modifications separately for male and female are proposed at couplet 3.

3 (male). Paramere strongly tapering with moderately rounded apex (Figs 18, 32§). Aedeagus slender or robust with wide apical lobe (Figs 14, 38§); median lobe from base at least slightly tapering to apex (Figs 13, 39§, 52§).................. 3a.

- Paramere slightly tapering with wide rounded apex (Fig. 17). Aedeagus moderately slender with narrow apical lobe (Fig. 12); median lobe in its greater part subparallel-sided (Fig. 11). Ligula long, widened to apical part ( Fig. 5 ). Coloration: usually dark. Length: 3.90–4.21 mm. Symbiotic host: Formica truncorum ................ Thiasophila szujeckii sp. n.

3a. Aedeagus robust (Fig. 14); apical lobe long, not widened about apex (Figs 14, 46§). Ligula long, subparallel-sided ( Figs 6 , 45§). Coloration: usually light. Length: 3.52–4.10 mm or 2.8–4.3 mm ( Zerche 1987). Symbiotic host: F. aquilonia , F. lugubris , F. polyctena , F. pratensis , F. rufa , F. sanguinea , F. truncorum , F. uralensis , Lasius brunneus , L. fuliginosus ............................................................................................ T. angulata

- Aedeagus slender (Fig. 40§); apical lobe short, slightly widened about apical (Fig. 38§). Ligula short, widened to apical part (Fig. 27§). Coloration: usually dark. Length: 2.80–3.70 mm. Symbiotic host: F. pratensis ................ T. lohsei 3 (female). Spermatheca: apical part semi-cylindrical or cylindrical (Figs 19–23, 41–43§); basal part short or long. Antenna: segment X 1.3 or 1.6 × as wide as long; segment XI 2.3 × or 2.8 × longer than segment X............................. 3a.

- Spermatheca: apical lobe semi-spherical or spherical (Figs 24–28, 54–58§); basal part short. Antenna: segment X 1.5 × as wide as long; segment XI 2.4 × longer than segment X. Ligula, coloration, length and symbiotic host the same as male......................................................................................... T. angulata

3a. Basal part of spermatheca elongated, 5–5.2 × longer than apical part, without dilatation (Figs 54–58§). Antenna: segment X 1.6 × as wide as long; segment XI 2.8 × longer than segment X. Ligula, coloration, length and symbiotic host the same as male..................................................................................................................................................................................... T. lohsei

- Basal part of spermatheca short, 3.5–4.2 × longer than apical part, with dilatation at about half of the length (Figs 19–23). Antenna: segment X 1.3 × as wide as long; segment XI 2.3 × longer than segment X. Ligula, coloration, length and symbiotic host the same as male............................................................. T. szujeckii sp. n.

Etymology. The new species is dedicated to the Polish coleopterologist and forest ecologist prof. Andrzej Szujecki, whose many fundamental researches have contributed much to the knowledge of Polish rove-beetles.

Distribution and natural history. T. szujeckii sp. n. discovered in south-eastern Poland ( Fig. 31 A) is probably broadly distributed in Europe. All specimens of the species were collected exclusively from Formica truncorum nest mounds in pine forest ( Fig. 31 ). Recently, our observations of the natural history (life cycle, phenology, seasonal abundance etc.) of T. angulata and T. szujeckii sp. n., in natural and laboratory conditions, were completed. These data will be provided in a future article.

Figures

FIGURE 29. Principal Component Analysis (PCA) with some morphometric data of T. szujeckii sp. n. (associated with F. truncorum) and T. angulata (associated with F. rufa and F. polyctena).

FIGURE 30. Phylogenetic tree (ML) of the T. angulata (H 1 – 3) and T. szujeckii sp. n. (H 4) haplotypes obtained based on COII sequence analysis. Boostrap values larger than 50 % above nodes were pointed.

FIGURE 31. The nest mound of Formica truncorum inhabited by T. szujeckii sp. n. with type locality (black circle on UTM map) of this species in Poland (A).

FIGURES 1 – 10. T. szujeckii sp. n. (1 – 5, 7 – 10), T. angulata (6). Dorsal habitus of holotype, male (1) and paratype, female (2) with microstructure (2 A – C, E) and posterior margin near posterolateral corner (2 D); right antenna of male (3) and female (4); ligula (5, 6); eighth sternite of male (7) and female (8); eighth tergite of of male (9) and female (10).

Tables

TABLE 2. Morphological differences between T. szujeckii sp. n., T. angulata and T. lohsei; measurements (in mm) – mean, standard error (SE), range;? – no data, (X) – figure number; X § – figure number and data of measurements by Zerche (1987). Assignment of various superscript letters indicates a highly significant difference (ANOVA, test Tukeya (HSD), p ≤ 0.05) between means.

Species Character	T. szujeckii sp. n. (N=30)	T. angulata (N=60)	T. lohsei (N=?)
Body length Head width	4.10 ±0.20 a, 3.90–4.21 0.57 ±0.035 a, 0.55–0.61	3.79 ±0.028 b, 3.52–4.10 or 2.8–4.3§ 0.47 ±0.0044 b, 0.46–0.53	2.8–3.7§?
Head length	0.44 ±0.043 a, 0.41–0.48	0.38 ±0.0044 b, 0.35–0.43	?
Pronotum width	0.90 ±0.042 a, 0.86–0.93	0.79 ±0.057 b, 0.75–0.83	?
Pronotum length	0.47 ±0.039 a, 0.43–0.50	0.43 ±0.0048 b,0.39–0.48	?
Pronotum: width to length ratio (mean)	1.91	1.84	1.56
Elytral width	1.01 ±0.053 a, 0.95–1.10	0.91 ±0.0080 b, 0.85–0.99	?
Abdomen width	0.97 ±0.054 a, 0.92–1.00	0.89 ±0.0076 b, 0.83–0.98	?
Colour	dark	light	dark
Antenna: length ratio of seg. XI and X	male: 2.4:1 female: 2.3:1	male: 2.5:1 female: 2.4:1	male: 2.4:1 (29§) female: 2.8:1
Antenna, ♀: width to length ratio of seg. X	1.3x	1.5x	1.6x
Ligula: shape	long, robust, widened to apical part (5)	long, slim, subparallel-sided (6, 45§)	short, slim, widened to apical part (27§)
Aedeagus: shape	moderately slender (12)	robust (14, 53§)	slender (40§)
Aedeagus: shape of apical lobe	narrow, short, not widened about apex (12, 12A), broadly rounded apically (15)	wide, long, not widened about apex (14, 46§), mildly rounded apically (16)	wide, short, slightly widened about apex (38§), broadly rounded apically (39§)
Aedeagus: shape of median lobe	in the greater part subparallel-sided (11)	distinctly tapering from base to apex (13, 52§)	slightly tapering from base to apex (39§)
Parameres: shape of apical lobe	slightly tapering and widely rounded apically (17)	strongly tapering and moderately rounded apically (18)	strongly tapering and moderately rounded apically (32§)
Spermatheca: shape, size of apical part	cylindrical, large (19–23)	spherical, small (24–28, 54– 58§)	cylindrical, large (41–43§)
Spermatheca: basal part	short	short	long
Spermatheca: dilatation on basal part	present (19–23)	lack (24–28, 54–58§)	lack (41–43§)
Host-associated	F. truncorum	F. aquilonia , F. lugubris , F. polyctena , F. pratensis , F. rufa , F. sanguinea , F. truncorum , F. uralensis , Lasius brunneus , L. fuliginosus	F. p r at e n s i s
Distribution	south-eastern Poland	Europe, partly Asia	Europe
Sources	present study	present study, Zerche 1987	Zerche 1987

TABLE 3. Pairwise genetic distances (K 2 P distances) based on 658 positions of COII sequences between haplotypes.

Haplotype	H1	H2	H3	H4
T. angulata (H1)	-
T. angulata (H2)	0.002	–
T. angulata (H3)	0.002	0.003	–
T. szujeckii sp. n. (H4)	0.011	0.011	0.012	–