Lebertia (Pilolebertia) porosa Thor, 1900

Tyukosova, Valentina, Gerecke, Reinhard, Stur, Elisabeth & Ekrem, Torbjørn, 2022, Disentangling the identity of Lebertia porosa Thor, 1900 using integrative taxonomy (Acari: Hydrachnidia), European Journal of Taxonomy 836 (1), pp. 131-169 : 144-150

Lebertia (Pilolebertia) porosa Thor, 1900

Fig. 7

Lebertia (Pilolebertia) porosa Thor, 1900: 273 , pl. 10 figs 3–4.

Diagnosis

Palp relatively large (L P-2>120, P-4> 150). P-3 stout (L/H ratio <2.1), with position of mediodistal seta rather variable (often halfway between, occasionally approaching the dorso- or ventrodistal one). P-4 ventral sectors between seta insertions decreasing in length from base to tip (in % total L: proximal sector 42–49, central sector 33–38, distal sector 15–22). I-L rather long (L I-L-4–6>170, 180, 160), IV- L-4–6 relatively stout (L/H ratio<4.1, 5.2, 4.6), terminal claw L> 70.

Type series

Missing. Type locality: Norway, “Lister, Flusz nahe bei Vanse Kirche”; no date, no information on number of specimens (at least one male).

Material examined

Neotype (here designated) NORWAY • ♂; Agder , Farsund , Vanse, stream at Vanse school; 58.10366° N, 6.69373° E; 6 m a.s.l.; 25 Jun. 2020; Torbjørn Ekrem and Thomas Stur Ekrem leg.; kick sample; BOLD specimen ID HYDCA568 (in ethanol); NTNU-VM 227972 .

Further material from type locality

NORWAY • 3 ♂♂; same collection data as for neotype; BOLD specimen ID HYDCA436 (in ethanol), HYDCA438 (slide mounted), HYDCA465 (in ethanol); NTNU-VM 228032 , 228034 , 228036 • 3 ♀♀; same collection data as for neotype; BOLD specimen HYDCA437 (in ethanol), HYDCA439 (slide mounted), HYDCA466 (in ethanol); NTNU-VM 228033 , 228035 , 228037 • 1 ♂; same collection data as for neotype; in ethanol; NTNU-VM 228040 • 2 ♀♀; same collection data as for neotype; in ethanol; NTNU-VM 228039 , 228041 • 3 ♀♀; same collection data as for neotype; in ethanol; NTNU-VM 228042 • 1 ♂; same collection data as for neotype; stream at playground; 58.09846° N, 6.69490° E; BOLD specimen ID HYDCA570 (slide mounted); NTNU-VM 228043 .

Other material (in ethanol unless otherwise stated)

NORWAY • 2 ♂♂, 2 ♀♀, 2 dn; “ Lebertia porosa Sig Thor 22-7-1899 Selsvand, Gudbr.dal. Sig Thor”; NHMO • 1 ♂; “ Lebertia (Pilolebertia) porosa S. Thor / 3-8-1899. Baverdal, Raubergstaltjern Sig Thor”; NHMO • 1 ♂, 9 ♀♀; “ L. porosa Sig Thor ”, “ Lebertia / 6-8-1898 Bekk ved Norbö [undecipherable] Jaderen Sig Thor”; NHMO • 1 ♂, 2 ♀♀; “ Leb. (Pilolebertia) porosa Sig Thor (+? ind.) [meaning unclear, vial was broken] 18/7.1899 Hattendal, Fjelstjörn v. Hatten Nordland ” [no collector, possibly coll. E. Strand, see Thor 1900 b]; NHMO • 4 ♀♀; “ Lebertia ? porosa Sig Thor / 24-7-1898, Baek nor Herikstad (Aagland) Jaederen / Teknes Sig Thor ; NHMO • 1 ♀; “ Pil. porosa S. T.”, “ Lebertia n. sp. NB (epimerora) [indecipherable] / 5-10-1900 Ljanselv. Sig Thor”; NHMO • 4 ♂♂, 2 ♀♀; “ L. (Pilolebertia) porosa Sig Thor (ikke rev.) / 17-7-1896 Himesjö naer Aamot, Österdalen, Norge leg. Sig Thor ”; NHMO • 2 ♀♀; “ Lebertia (Pilolebertia) ? porosa Sig Thor / 13-7-1897, Landöelv, Senjen Dr. Sig Thor ”; NHMO • 2 ♀♀; “ Leb. ( Piloleb. ) porosa Sig Thor ? var. / 19-7-1897 Stor vandet (Hammerfest) ½ aq. + ½ v.l. Sig Thor”; NHMO • 6 ♂♂, 3 ♀♀, 1 dn; “ Lebertia (Piloleb.) porosa Sig Thor. / 26-7-1897, Tsoalmejarve, Syd-Varang. Finnmarken N. Sig Thor”; NHMO • 2 ♂♂, 2 ♀♀; “ Lebertia (Pilol.) ? porosa Sig Thor / 29-8-1900, Balsokvand, Balsfjord Nordm.”; NHMO • 1 ♀; “ Lebertia porosa sp.n. Sig Thor / 22-7- 1900. Elv ved Alteid (Tromsöand) Sig Thor”; NHMO • 3 ♂♂; “ Lebertia (Piloleb.) porosa Sig Thor. 16/8 1899 Raubergstult. / 16-8-1899 Raubergstultjern Baverdal, Gudbr.dal, Sig Thor”; NHMO • 1 ♀; “ Leb. ( Pilolebertia ) cfr. porosa ST. / 14-7-1898 Kittelsav i Torrisdal n. sten og mos paa bunden ST”; slide mounted; NHMO • 1 ♂; “ Lebertia insignis Neum. ♂ Cotype. / Norwegen. Hjatdala [!] Hjartdal. 29.7.1901 S. Thor leg. 2001”; SMF 44901 • 1 ♂; “ Lebertia insignis Neum. ♂ Cotype. S. Thor 1900 / Norwegen. Selsvand, Gudbrandsdal 22.7.1899 Thor leg. 2005”; slide mounted; SMF 44902 • 1 ♀; “ Lebertia insignis Neum. ♀ Cotype / Norwegen. Selsvand , 7.1899 Thor leg. 2006”; slide mounted; SMF 44903 • 1 ♀; “ Lebertia (Piloleb.) porosa var. Sig. Thor Cotype ♀ / Norwegen Larvik, Farris-elv. 2.11.1913. S. Thor leg. et det. 1691”; slide mounted; SMF 45001 • 1 ♂; “ Lebertia (Piloleb.) porosa var. Sig. Thor Cotype ♂ / Norwegen Larvik, Farris-elv. 2.11.1913. S. Thor leg. et det. 1693”; slide mounted; SMF 45002 • 1 ♂; Agder, Flekkefjord, Flikkeid , creek at Flikkeid 18; 58.35775° N, 6.62518° E; 56 m a.s.l.; 24 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; BOLD specimen ID HYDCA556 ; NTNU-VM 227997 • 2 ♂♂, 1 dn; same collection data as for preceding; NTNU-VM 227998 , 227999 • 1 ♂; Agder, Froland, inlet stream to Horvedalstjenn , upstream bridge, intersection Lyngrothveien ; 58.52377° N, 8.67591° E; 53 m a.s.l.; 28 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; BOLD specimen ID HYDCA312 ; NTNU-VM 228004 • 1 ♂; Agder, Flekkefjord, Lundevatn at Sira , Sirneset ; 58.40630° N, 6.62017° E; 48 m a.s.l.; 24 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; slide mounted; NTNU-VM 228000 • 1 ♀; Agder, Kristiansand, creek at bridge close to Nedre Timenes vei nr. 51; 58.16324° N, 8.10116° E; 1 m a.s.l.; 27 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; drift sample; BOLD specimen ID HYDCA270 (slide mounted); NTNU-VM 228001 • 1 ♂; Agder, Kristiansand, Kvernbekken , at Kjos ; 58.11431° N, 7.95185° E; 1 m a.s.l.; 27 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; BOLD specimen ID HYDCA275 (slide mounted); NTNU-VM 228002 • 1 ♀; same collection data as for preceding; BOLD specimen ID HYDCA276 (slide mounted); NTNUVM 228003 • 1 ♀; Agder, Kristiansand, Prestebekken , close to Jegersberg gård; 58.16420° N, 8.00735° E; 4 m a.s.l.; 2 Sep. 2019; Reinhard Gerecke and Torbjørn Ekrem leg.; BOLD specimen ID HYDCA340 ; NTNU-VM 228029 • 2 ♀♀, 1 dn; same collection data as for preceding; NTNU-VM 228030 • 1 ♂; Agder, Kristiansand, Nedre Jegersbergvann , inlet flow stream; 58.16920° N, 8.00007° E; 21 m a.s.l.; 2 Sep. 2019; Reinhard Gerecke and Torbjørn Ekrem leg.; BOLD specimen ID HYDCA560 ; NTNU-VM 228028 • 1 ♀; Agder, Lillesand, Badstudalen nature reserve , creek in Eigedalen ; 58.20614° N, 8.23545° E; 43 m a.s.l.; 22 Jun. 2020; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA566 ; NTNU-VM 228031 • 1 ♂, 2 ♀♀; Agder, Songdalen, Stavbekken , at Dynamitten ; 58.15848° N, 7.81138° E; 45 m a.s.l; 30 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; BOLD specimen ID HYDCA425 (slide mounted), HYDCA426 (slide mounted), HYDCA452 ; NTNU-VM 228008 , 228009 , 228010 • 3 ♂♂, 2 ♀♀; same collection data as for preceding; NTNU-VM 228011–228013 (slide mounted), 228014 ; • 2 ♂♂, 1 ♀; Agder, Søgne, Søgneelva , upstream bridge close to old Søgne Church ; 58.08952° N, 7.83998° E; 2 m a.s.l.; 30 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; BOLD specimen ID HYDCA286 (slide mounted), HYDCA460 , HYDCA461 ; NTNU-VM 228005 , 228016 , 228017 • 1 ♂, 2 ♀♀; same collection data as for preceding; NTNU-VM 228006 , 228007 , 228018 • 1 ♂; same locality as for preceding; 21 Jun. 2020; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA435 (slide mounted); NTNUVM 228015 • 5 ♀♀; same collection data as for preceding; NTNU-VM 228019 • 3 ♂♂, 3 ♀♀; Agder, Søgne, Søgneelva , Ved Fossheia ; 58.09047° N, 7.83637° E; 3 m a.s.l.; 30 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; BOLD specimen ID HYDCA294 , HYDCA295 , HYDCA430 , HYDCA431 , HYDCA458 , HYDCA459 ; NTNU-VM 228020 to 228025 • 3 ♂♂, 1 ♀; same collection data as for preceding; NTNU-VM 228026 , 228027 • 1 ♂; Møre og Romsdal, Eide, Nåsvassdraget, Sagelva , station 1; 62.89968° N, 7.42313° E; 8 m a.s.l.; 14 Sep. 2016; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA216 (slide mounted); NTNU-VM 228050 • 1 ♀; same collection data as for preceding; NTNUVM 228051 • 1 ♂; Telemark, Drangedal, Engåa , creek; 59.03875° N, 9.28733° E; 71 m a.s.l.; 17 Jun. 2020; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA369 (slide mounted); NTNU-VM 227992 • 1 ♀; same collection data as for preceding; BOLD specimen ID HYDCA370 (slide mounted); NTNUVM 227993 • 4 ♀♀; same collection data as for preceding; NTNU-VM 227994 to 117996 • 1 ♀; Trøndelag, Meråker, Stjørdalsvassdraget , Stjørdalselva , station 6; 63.44283° N, 11.62808° E; 92 m a.s.l.; 26 Apr. 2016; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA538 ; NTNU-VM 228047 • 2 ♀♀; Trøndelag, Stjørdal, Stjørdalselva at Hegra ; 63.46305° N, 11.08623° E; 4 m a.s.l.; 3 Jul. 2020; Valentina Tyukosová and Torbjørn Ekrem leg.; BOLD specimen ID HYDCA456 , HYDCA572 ; NTNUVM 228044, 228045 • 1 ♀; Trøndelag, Stjørdal, Stjørdalsvassdraget , Stjørdalselva , station 1; 63.46251° N, 11.09256° E; 33 m a.s.l.; 26 Apr. 2016; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA537 ; NTNUVM 228046 • 1 ♂; Trøndelag, Stjørdal, Stjørdalsvassdraget , Stjørdalselva , station 8; 63.41707° N, 11.73635° E; 99 m a.s.l.; 30 Aug. 2018; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA165 (slide mounted); NTNU-VM 228048 • 1 ♀; same collection data as for preceding; NTNU-VM 228049 .

SWEDEN • 1 ♀; “granskad av Thor 1925 / Pilolebertia porosa Sig Thor. ♀ var. Jytland: Linding Aa vid Varde. Vid inloppet i Nörholm Skov. Vattentemp. + 14°C, kl. 7 c.m. Leg. J.K. Findal. 15.6.1928. 428.”; NHRS GULI000086301 .

Description

Idiosoma colouration pale brown with an irregular yellowish median line surrounded by a darker area, lateral eye pigment red, appendages pale brown. Integument smooth, with a very fine porosity, in some specimens after enzymatic digestion a very fine striation becomes visible. Coxal field with mL Cx-I> Cx-II (ratio 1.1–1.3). Posterior margin of Cx-IV equally rounded or, in aged adults, only weakly convex in part facing V-3, posteromedial part turning in an abrupt curve to genital bay. Genital bay with nearly straight, anteriorly converging lateral margins and obtuse anterolateral angles at level of pregenital sclerite. Genital flaps with sexual dimorphism in setation, anterior and central Ac elongate, posterior Ac roundish.

Legs rather long, but distal segments of hind leg stout. Swimming setation: II-L-5 6–7; III-L-4 5–7; III-L-5 4–12; IV-L-4 5–10; IV-L-5 9–12.

Gnathosoma (lateral view) ventral margin in basal part equally convex, in distal part straight or very weakly concave, without a kink near mouth opening area. Chelicera slender as typical in most Lebertia , with short claw (L/H ratio 6.4–7.4, basal segment/claw ratio 4.5–5.4). Palp relatively stout; P-2 dorsal margin more strongly curved in basal part than distally, ventral margin equally concave, with a slight protrusion at base of ventral seta, 5–6 dorsal setae; P-3 stout, dorsal and ventral margins only slightly diverging from base to tip, with five setae: one proximomedial and one dorsocentral, three medially at distal margin, typically at equal distance (mediodistal seta halfway between dorsodistal and ventrodistal one), but mediodistal setae may approach one of the two others. P-4 maximum H in proximal quarter, from here towards tip of segment equally narrowed; fine ventral setae dividing ventral segment margin into three sectors of unequal size, with proximal one largest and distal one shortest, but distoventral seta always further away from distoventral edge than its insertion point from dorsal margin; mediodistal peg setae strong and blunt, dorsally 6–8 fine setae, all restricted to a small groove in distalmost part of segment.

Males

Idiosoma L 1000–1320; coxal shield L 750–830; Cx-I/II mL 210–220/170–180. Genital field L/W 150– 205/160–175; L Ac-1 70–75, L Ac-2 55–70, L Ac-3 40–50; genital flaps with ca 50 pairs of setae at medial margin, arranged in a single line on level of Ac-1, in a double line near Ac-2, and in triple line near Ac-3.

Leg measurements (L/H, ratio): I-L-4 169–195/59–73, 2.73–2.96; I-L-5 187–205/48–58, 3.48–3.91; I-L-6 161–180/42–50, 3.50–3.95; IV-L-4 290–313/75–80, 3.63–4.12; IV-L-5 310–534/57–68, 4.90– 5.42; IV-L-6 279–315/57–75, 4.20–5.11; proportions of segments (L ratio): IV-L-4/5 0.90–0.96, IV-L- 4/6 0.97–1.06, IV-L-5/6 1.08–1.12; IV-L claw L 75–85.

Palp measurements (L/H, ratio, % total L): P-1 40–43/58–60, 0.7, 8%; P-2 125–143/81–95, 1.46–1.70, 27–28%; P-3 99–123/58–68, 1.61–1.85, 23–24%; P-4 147–163/46–53, 2.92–3.20, 31%; P-5 49–50/9, 5.56–5.74, 9–10%; proportions of segments (L ratio): P-2/P-3 1.14–1.40, P-2/P-4 0.84–0.91, P-3/P-4 0.64–0.73; distance ratio distal setae P-3 (A/B) 0.69–1.38; P-4 ventral sectors 42–53%, 29–36%, 18- 22%; dorsal/ventral L ratio 1.16–1.22; palp total L 513–516.

Females

Idiosoma L 1200–1300; coxal shield L 820–830; Cx-I/II mL 205–230/175–185. Genital field L/W 220– 230/175–190; L Ac-1 70, L Ac-2 60–65, L Ac-3 50–55; genital flaps with ca 20 pairs of setae in a single line at medial margin.

Leg measurements (L/H, ratio): I-L-4 183–202/64–73, 2.74–3.03; I-L-5 198–216/53–60, 3.58–3.88; I-L-6 176–198/45–55, 3.45–4.00; IV-L-4 308–345/77–90, 3.74–4.25; IV-L-5 319–375/64–73, 4.86– 5.33; IV-L-6 319–340/68–80, 4.00–4.74; proportions of segments (L ratio): IV-L-4/5 0.91–0.97, IV-L- 4/6 0.97–1.07, IV-L-5/6 1.06–1.12; IV-L claw L 80–85.

Palp measurements (L/H, ratio, % total L): P-1 38–40/58–59, 0.65–0.68, 8%; P-2 132–150/88–97, 1.49– 1.62, 28%; P-3 95–128/57–73, 1.65–1.83, 24%; P-4 155–174/51–59, 2.91–3.21, 32%; P-5 50–53/9, 5.56–5.83, 9–11%; proportions of segments (L ratio): P-2/P-3 1.13–1.40, P-2/P-4 0.78–0.89, P-3/P-4 0.68–0.74; distance ratio distal setae P-3 (A/B) 0.50–1.00; P-4 ventral sectors 47–48%, 33–38%, 15– 19%; dorsal/ventral L ratio 1.18; palp total L 500–539.

Remarks

In the original description, Thor (1900: pl. 10 figs 3–4) included a reference to two figures, but he later ( Thor 1906) stated that these figures show L. porosa obscura . Thus, no figure in the original description is ascribed to L. porosa . Characters considered diagnostic by Thor was the body colouration (idiosoma dark brown with yellow dorsal line) and the formation of the integument (thick, densely covered by name-giving fine pores – these pores “stronger and more apparent than in L. insignis and L. vigintimaculata ”). The described fine, line-like folds in the integument were later considered artifacts ( Thor 1902). A lineation as it is typical in many species of other subgenera has not yet been found in any species of Pilolebertia . Further characters given in the original description are as follows: idiosoma L/W 1400/1200–1300; palps and legs very thick; legs with rich swimming setation; coxal field as in L. insignis / vigintimaculata , but suture Cx-III/IV directed “a bit more laterally”; Cx-IV occasionally with a small indentation “within the large pore” (probable meaning: posterior margin of Cx-IV in the part facing V-3 slightly flattened or concave, as given by Thor (1900: fig. 3) for L. obscura ). No taxonomic significance can be attributed to differences in porosity patterns of the integument of species of Pilolebertia , density and size of pores most probably being age dependent.

At the time of its description, the species had to be distinguished from two other species of the subgenus Pilolebertia : Lebertia inaequalis Koch, 1837 , which could be separated by having both ventral setal pores of P- 4 in the distal part of the segment, the distal one very close to the distal segment edge, peg seta of P-4 very small, not longer than high, and by having a gnathosomal ventral margin with a kink near the mouth opening; and L. insignis Neuman, 1880 , which could be separated by having the distomedial seta on P-3 very close to the distoventral one, ratio 0.29–0.33. The latter species is similar to L. porosa and differs from L. inaequalis in having the gnathosoma without a distal kink and in the rather large distomedial peg seta on P-4. Our data reveal that L. insignis can be distinguished from both compared species also by the insertion of the ventral setae on P-4, with the central sector longer than both the proximal and distal sectors. This species is also unique in having the proximal and distal sectors nearly equal in size (L ratio 0.84–1.07; in most other genetic lineages the proximal sector is relatively enlarged, L ratio>1.1).

Redefining Lebertia porosa after material collected at its type locality was more complicated than expected, as representatives of three distinct genetic clades were detected at the same site, all with porosa -like character combinations following Gerecke (2009). Two findings helped us to attribute one of these clades to L. porosa : (1) one of the three clades could be clearly distinguished from L. porosa on the basis of morphological features (most probably, this taxon had already been found by Thor in Norway as well, but not at this site; it represents L. gibbosa Lundblad, 1926 , see below); (2) syntypes of L. obscura found at NHMO could be attributed to the second of these clades. Through an elimination process it was thus possible to attribute the third clade from the Vanse locality to L. porosa .

The indication “Cotype” on the labels of specimens of Lebertia insignis and L. porosa in SMF (see above) are obviously incorrect, but all the specimens in question (SMF 44901–44903 and 45001–45002) are in good agreement with the definition given for L. porosa .

During the first quarter of the past century, nine porosa -like species of Lebertia were described, all listed as junior synonyms ( Gerecke 2009): Lebertia pachydermis Koenike, 1908 ; L. lacertosa Koenike, 1911 ; L. saxonica Thor, 1911 ; L. seclusa Koenike, 1914 ; L. rivalis Koenike, 1918 ; L. violacea K. Viets, 1921 ; L. violacea lurida K. Viets, 1921 ; L. leioderma K. Viets, 1925 ; L. porosa curvata K. Viets, 1925 . The type material of L. saxonica has not been found. For all other species, types could be investigated for comparison with the material included in our study here. For several of these species, a synonymy with L. porosa or L. obscura is probable. For others, a revival or their designation as nomina dubia is possible. Comparative studies to clarify this are ongoing and it is too early to present results, but the character states of all these species are distinctly different from the character combination diagnostic for L. gibbosa . Hence, there is no doubt about the taxonomic stability of the latter.

Lebertia riabuschinskii Thor, 1926 was listed by Gerecke (2009) as a synonym of L. porosa , erroneously referring to Besseling (1958). Lundblad (1956) and later authors proposed to synonymize L. riabuschinskii with L. inaequalis . In fact, data kindly made available by A. Shatrov on material conservated at ZISP confirm that material attributed to L. riabuschinskii (no type material exists) is morphologically close to L. inaequalis . The same is true for two specimens from Finland in SMF, labelled as L. riabuschinskii . This species will be treated in a projected revision of the L. inaequalis group.

Before this revision, L. porosa was considered a eurytopic and euryoecious species with a Holarctic distribution ( Gerecke 2009). Our results show that both distribution and ecology need to be revised on a broader scale for accuracy, taking into account that populations in other regions likely represent species other than L. porosa . At present the ‘true’ Lebertia porosa is recorded from middle order streams at low altitudes (up to 220 m a.s.l.) in Norway and Sweden only, but in a wide range of geographical latitudes from Agder in the south (58° N) to Finnmark in the north (69° N).

Figures

Fig. 7. Lebertia (Pilolebertia) porosa Thor, 1900, ♂ from the type locality. A. Venter. B. Palp. C. I-L. D. II-L. E. III-L. F. IV-L. Scale bars = 100 µm.