Lebertia (Pilolebertia) gibbosa Lundblad 1926
Creators: name: Tyukosova, Valentina
name: Gerecke, Reinhard
name: Stur, Elisabeth
name: Ekrem, Torbjørn
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Trombidiformes
Lebertiidae
Lebertia
Lebertia gibbosa

description: Lebertia (Pilolebertia) gibbosa Lundblad, 1926
Fig. 9
Lebertia gibbosa Lundblad, 1926: 206.
Diagnosis
Small in dimensions of appendages (e.g., palp total L<420, L IV-L-4–6 <260, 290, 260); P-2 short (L 90–105), dorsal margin protruding to form a hump-like edge near insertion of dorsal setae, distoventral seta long (about 110). P-3 (L/H 2.2–2.4) and P-4 (L/H 3.0–3.7) very slender, L ratio P-2/P-3 0.9–1.0, P-3/P-4 0.8–0.9. Mediodistal seta P-3 away from dorsodistal seta (L ratio sectors A/B 1.7–1.8). Ventral seta of P- 4 in distal part, distoventral one close to distoventral segment edge (L ventral sectors 57–67, 24–34, 8–9%).
Material examined
Holotype SWEDEN • ♂, “923. Typ (360) Lebertia gibbosa Lundbl. ♂. Östergötland: Kisa rocken. Vålens tillopp. 28.06.1917, leg. O. Lundblad ”; slide mounted; NHRS.
Other material (in ethanol unless otherwise stated)
NORWAY • 1 ♂; 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 HYDCA467; NTNU-VM 227896 • 1 ♂; Agder, Farsund, Vanse, stream at playground; 58.09846° N, 6.69490° E; 6 m a.s.l.; 25 Jun. 2020; Torbjørn Ekrem and Thomas Stur Ekrem leg.; kick sample; BOLD specimen ID HYDCA569; NTNU-VM 227897 • 1 ♂, 2 ♀♀, 1 dn; Agder, Froland, Nidelva, near Blakstad, upstream bridge Frolandsveien, E riverbank; 58.51004° N, 8.64806° E; 40 m a.s.l.; 28 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; BOLD specimen ID HYDCA306, HYDCA 429, HYDCA454, HYDCA455; NTNU-VM 227882 to 227885 • 2 ♂♂, 2 ♀♀; Agder, Søgne, Søgneelva, upstream bridge close to old Søgne Church; 58.08952° N, 7.83998° E; 2 m a.s.l.; 21 Jun. 2020; Gaute Kjaerstad and Reinhard Gerecke leg.; BOLD specimen ID HYDCA432 (slide mounted), HYDCA433 (slide mounted), HYDCA 462, HYDCA463; NTNU-VM 227886 to 227889 • 1 ♂, 2 ♀♀; same collection data as for preceding; slide mounted; NTNU-VM 227891 to 227893 • 2 ♂♂, 2 ♀♀; same locality as for preceding; 30 Aug. 2019; NTNU-VM 227890 • 1 ♂; Agder, Søgne, Flomdam, Søgneelva upstream bridge near old Søgne church; 58.08962° N, 7.83937° E; 2 m a.s.l.; 30 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; BOLD specimen ID HYDCA558; NTNU-VM 227894 • 1 ♂; same collection data as for preceding; NTNU-VM 227895 • 1 ♀, 1 dn; Trøndelag, Orkdal, Orklavassdraget, Sagbekken, station 1; 63.24614° N, 9.67573° E; 175 m a.s.l.; 26 Jul. 2018; Gaute Kjaerstad leg.; NTNU-VM 227998.
Description
Colour in life unknown. Integument with a fine porosity. Coxal field with medial sutures Cx-I slightly longer than medial sutures Cx-II (ratio about 1.2), Cx-II posteromedially forming a narrow, acute angle. Posterior margin of Cx-IV equally rounded or forming an obtuse angle near apodeme in medial sector. Swimming setation: II-L-5 4–5; III-L-4 4–5; III-L-5 7–9; IV-L-4 4–5; IV-L-5 7–9. Chelicera L/H ratio 8.0, basal segment/claw ratio 7.0.
Males
Idiosoma L 1060, coxal shield 740, Cx-I/II mL 190/165. Genital field L/W 190/130, with 34–44 medial setae; Ac-1–3 L 65, 50, 35. Gnathosoma L 200; chelicera basal segment L 270, H 55; claw 60.
Leg measurements (L/H, ratio): I-L-4 121–132/46–48, 2.62–2.86; I-L-5 125–138/37–40, 3.35–3.65; I-L-6 99–125/35–38, 2.81–3.35; IV-L-4 227–240/48–55, 4.36–4.86; IV-L-5 242–260/37–43, 6.12–6.47;
IV-L-6 207–225/40, 5.22–5.63; proportions of segments (L ratio): IV-L-4/5 0.92–0.94, IV-L-4/6 1.07– 1.10, IV-L-5/6 1.15–1.17; IV-L claw L 50.
Palp measurements (L/H, ratio, % total L): P-1 30/43, 0.7, 8; P-2 92–96/60–62, 1.5–1.6, 25; P-3 97– 103/44–45, 2.2–2.3, 27; P-4 112–123/36–38, 3.1–3.3, 32; P-5 33/5, 7,2, 8; proportions of segments (L ratio): P-2/P-3 0.94–0.96, P-2/P-4 0.79–0.82, P-3/P-4 0.83–0.86; distance ratio distal setae P-3 (A/B) 1.67; P-4 ventral sectors 63%, 28%, 9%; palp total L 384.
Females
Idiosoma L 900–1200; coxal shield 720–750; Cx-I/II mL 210–225/170. Genital field L/W 180–190/150, with 18–24 medial setae; Ac-1–3 L 55–60, 55–60, 38–40. Gnathosoma L 210; chelicera basal segment L 210, H 30; claw 30.
Leg measurements (L/H, ratio): I-L-4 145/50, 2.90; I-L-5 150/40, 3.75; I-L-6 130/38, 3.47; IV-L- 4 255/60–65, 3.92–4.25; IV-L-5 273–280/48–55, 4.95–5.89; IV-L-6 240–250/43–45, 5.33–5.88; proportions of segments (L ratio): IV-L-4/5 0.91–0.94, IV-L-4/6 1.02–1.06, IV-L-5/6 1.12–1.14; IV-L claw L 50–55.
Palp measurements (L/H, ratio, % total L): P-1 31–33/43–45, 0.7, 8; P-2 100–103/63–65, 1.6, 24–25; P-3 110–113/48, 2.3–2.4, 27; P-4 130–138/38–39, 3.4–3.7, 32–33; P-5 33/5, 7.2, 8; proportions of segments (L ratio): P-2/P-3 0.91, P-2/P-4 0.73–0.79, P-3/P-4 0.80–0.87; distance ratio distal setae P-3 (A/B) 1.80; P-4 ventral sectors 57–67 %, 24–34 %, 8–9 %; palp total L 410–411.
Remarks
The meagre original description is without measurement data and refers in most details to character states typical for all species of the subgenus Pilolebertia (Lundblad 1926). The only diagnostic feature mentioned is the name-giving shape of P-2, elevated to form an obtuse-angled hump. Lundblad’s fig. 5 shows a palp with P-3 having the mediodistal seta approaching the dorsodistal seta (calculated ratio A/B ca 2.0). P-3/-4 slender (L/H ratio 2.1, 2.9), P-3 proportionally long (L ratio P-3/4 0.85).
Lebertia gibbosa fits the characteristics of the porosa -like Lebertia species in the absence of a kink in the distoventral gnathosomal margin, but distinct differences are found in the characteristic, namegiving hump of P-2, the slender palp segments P-3 and P-4, the position of the ventral setae (both in distal half, proximal sector>50%), and the small size of the distal peg seta on P-4. The P-4 size is similar to that in L. inaequalis (Koch, 1837), and application of the key in Gerecke (2009) is misleading, keying L. gibbosa to L. inaequalis. Lebertia inaequalis agrees with L. gibbosa also in the swimming setation, but differs, in addition to the ventral kink of the gnathosoma, in having a P-2 with its dorsal margin equally curved, not protruding to form a hump, and P-3 with mediodistal seta not, or only slightly, approaching the dorsodistal seta. A comparison with measurements of Norwegian specimens morphologically attributed to L. inaequalis reveals a wide overlap in many dimensions and proportions. The latter differ from L. gibbosa in having a more slender I-L-6 (L/H>3.7), longer IV-L claws (> 55) and a higher P-2/P-3 ratio (> 1.0). DNA barcode data in BOLD indicate that L. inaequalis, similar to what is shown here for L. porosa aggr., represents a species complex with several BINs under this name. Upon taxonomic revisions, we expect that the wide variability for leg proportions of L. inaequalis described by Gerecke (2009) will cover a range of several distinct species.
Before our study, this species was only known from its type locality on the island of Gotland (Sweden). Our data show a wide distribution in southern Norway, in the north reaching up to southern Trøndelag County (63° N). As this species has been widely overlooked, the full geographical distribution of L. gibbosa cannot be defined without additional research.
description: Published as part of Tyukosova, Valentina, Gerecke, Reinhard, Stur, Elisabeth & Ekrem, Torbjørn, 2022, Disentangling the identity of Lebertia porosa Thor, 1900 using integrative taxonomy (Acari: Hydrachnidia), pp. 131-169 in European Journal of Taxonomy 836 (1) on pages 154-156, DOI: 10.5852/ejt.2022.836.1921, http://zenodo.org/record/7084410