Lebertia (Pilolebertia) obscura 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 : 150-153

Lebertia (Pilolebertia) obscura Thor, 1900

Fig. 8

Lebertia (Pilolebertia) porosa obscura Thor, 1900: 273 .

Diagnosis

Palp relatively large (L P-2 ≥130, P-4 ≥ 150). P-3 stout (L/H <1.9), with position of mediodistal seta rather variable (often halfway between, occasionally approaching the dorso- or ventrodistal one). P-4 ventral sectors between seta insertions various, in many cases decreasing in length from base to tip (in % total L: proximal sector 35–55, central sector 22–45, distal sector 17–27). I-L rather long (L I-L- 4–6>165, 185, 160), IV-L-4–6 relatively slender (L/H ratio>4.1, 5.9, 4.7); terminal claw L<60.

Type series

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

Material examined

Lectotype (here designated) NORWAY • ♂; “20-7-98 Elv fra Prest ved Vanse (Listerland) Sig Thor / Lebertia ? n. sp. obscura ” [Agder, Farsund, Lister, Vanse, stream at Vanse vicarage]; 58.10366° N, 6.69373° E; 6 m a.s.l.; 20 Jul. 1898; Sig Thor leg.; in ethanol; one II-L, one IV-L detached; NHMO.

Paralectotypes NORWAY • 1 ♀; same collection data as for lectotype; NHMO • 2 ♀♀; “ Lebertia porosa ST + obscura Sig Thor / 20-7-1898. Elv pa Vanse, Lister, Sig Thor”; slide mounted; NHMO .

Other material (in ethanol unless otherwise stated)

NORWAY • 3 ♂♂, 3 ♀♀; “ Lebertia porosa ST + var. obscura Sig Thor / 13-8-1901. Elv ved Vanse, Lister, Sig Thor”; slide mounted; NHMO • 4 ♂♂, 11 ♀♀; “ 17-8-1901. Slavdalsvand, Lister. Sig Thor / Lebertia porosa S. T. v. obscura S. T.”; of these, 2 ♂♂ and 2 ♀♀ slide mounted; NHMO • 3 ♀♀; same collection data as for preceding, “Thymol”; NHMO • 1 ♂; same collection data as for preceding; “ Lebertia obscura ”; NHMO • 1 ♀; “ K. Viets 45040”, “ Lebertia porosa obscura S. Thor Cotype / Norwegen Lister 17.8.1901 S. Thor leg. 2004”; slide mounted; SMF • 1 ♀; Agder, Farsund, Vanse , stream at Vanse school [type locality]; 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 HYDCA464 ; NTNU-VM 227971 • 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 HYDCA571 ; NTNU-VM 227973 • 1 ♂, 1 ♀; Agder, Flekkefjord, Lake Lundevatn at Sira , Sirneset ; 58.40630° N, 6.62017° E; 48 m a.s.l.; 24 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; BOLD specimen ID HYDCA442 , HYDCA443 ; NTNU-VM 227961 , 227962 • 2 ♀♀; same locality as for preceding; slide mounted; NTNU-VM 227963 , 227964 • 2 ♂♂, 1 ♀; Agder, Kristiansand, Foss , Jordfallbekken , downstream at bridge; 58.26850° N, 8.16259° E; 26 m a.s.l.; 26 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; BOLD specimen ID HYDCA236 , HYDCA237 , HYDCA278 (all slide mounted); NTNU-VM 227966 , 227967 , 227965 • 4 ♀♀; same locality as for preceding; NTNU-VM 227978 • 1 ♂, 1 ♀; Agder, Kristiansand, Songdalen , creek close to Oxbow Lake at Bruhaugen ; 58.15623° N, 7.82584° E; 12 m a.s.l.; 21 Jun. 2020; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA564 , HYDCA565 ; NTNU-VM 227968 , 227969 • 2 ♂♂; same locality as for preceding; slide mounted; NTNU-VM 227980 • 1 ♂; Agder, Kristiansand, Søgne , Flomdam , Søgneelva , upstream of the bridge at old Søgne church; 58.08962° N, 7.83937° E; 2 m a.s.l.; 30 Aug. 2019; Gaute Kjaerstad and Reinhard Gerecke leg.; NTNU-VM 227979 • 1 ♀; Agder, Lillesand, Badstudalen nature reserve , Fanturheia ; 58.20626° N, 8.23249° E; 45 m a.s.l.; 22 Jun. 2020; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA567 ; NTNU-VM 227970 • 2 ♀♀, 4 dn; Agder, Lillesand, Badstudalen nature reserve , stream in Eigedalen ; 58.20614° N, 8.23545° E; 43 m a.s.l.; 22 Jun. 2020; Gaute Kjaerstad leg.; NTNU-VM 227981 • 1 dn; Nordland, Vefsn, Drevvatnet , station 3; 66.048° N, 13.387° E; 47 m a.s.l.; 10 Jun. 2013; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA42 (slide mounted); NTNU-VM 227943 • 2 ♀♀; Nordland, Vefsn, Drevvatnet , station 1; 66.052° N, 13.364° E; 47 m a.s.l.; 11 Aug. 2014; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA17 , HYDCA78 (both slide mounted); NTNU-VM 227944 , 227945 • 1 ♂; Nordland, Vefsn, Drevjavassdraget, Drevvatnet , station 2; 66.0674° N, 13.416° E; 47 m a.s.l.; 9 Aug. 2016; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA180 (slide mounted); NTNU-VM 227975 • 4 ♀♀, 1 ♂; Nordland, Vefsn, Fustvatnet , station 1; 65.907° N, 13.361° E; 38 m a.s.l.; 13 Aug. 2014; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA6 , HYDCA9 , HYDCA90 , HYDCA91 , HYDCA93 (all slide mounted); NTNU-VM 227946 to 227950 • 1 ♀; Nordland, Vefsn, Fustvatnet , station 3; 65.906° N, 13.432° E; 38 m a.s.l.; 13 Aug. 2014; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA14 (slide mounted); NTNU-VM 227951 • 1 ♂; Nordland, Vefsn, Fusta vassdraget, Fustvatnet , station 3; 65.9061° N, 13.432° E; 38 m a.s.l.; 11 Aug. 2016; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA175 (slide mounted); NTNU-VM 227974 • 1 ♂, 2 ♀♀; Telemark, Drangedal, Engåa (pool); 59.03855° N, 9.28759° E; 71 m a.s.l.; 17 Jun. 2020; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA335 , HYDCA367 , HYDCA368 (all slide mounted); NTNU-VM 227952 to 227954 • 1 ♀; same locality as for preceding; NTNU-VM 227976 • 3 ♂♂, 1 ♀; Telemark, Drangedal, Krossbekken , at gate; 59.04808° N, 8.70406° E; 464 m a.s.l.; 20 Aug. 2019; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA326 (slide mounted), HYDCA327 , HYDCA450 , HYDCA451 ; NTNU-VM 227955 to 227958 • 17 ♂♂, 7 ♀♀; same locality as for preceding; of these, 2 ♂♂ slide mounted; NTNU-VM 227977 , 227959 , 227960 • 1 ♂; Trøndelag, Orkdal, Orklavassdraget , Sagbekken , station 1; 63.24614° N, 9.67573° E; 175 m a.s.l.; 26 Jul. 2018; Gaute Kjaerstad leg.; BOLD specimen ID HYDCA199 ; NTNU-VM 227990 • 2 ♂♂, 1 ♀; Trøndelag, Stjørdal, Stjørdalsvassdraget , Stjørdalselva , station 8; 63.41707° N, 11.73635° E; 99 m a.s.l.; 30 Aug. 2018; Gaute Kjaerstad leg.; NTNU-VM 227988 , 227989 • 6 ♂♂, 6 ♀♀, 2 dn; Trøndelag, Stjørdal, Hegra , opposite of gas station at E14; 63.4631° N, 11.0853° E; 71 m a.s.l.; 3 Jul. 2020; Torbjørn Ekrem and Valentina Tyukosová leg.; NTNU-VM 227982 to 227989 .

Description

In good agreement with the description given above for L. porosa (corresponding details not repeated here). Colouration of appendages dark blue green. Coxal field with mL Cx-I>Cx-II (ratio 1.1: 1.7). Legs rather long, distal segments of hind leg relatively slender. Swimming setation: II-L-5 2–9; III-L-4 6–10; III-L-5 8–14; IV-L-4 6–9; IV-L-5 7–12. Chelicera L/H ratio 7.3–7.8, basal segment/claw ratio 5.8–8.1.

Males

Idiosoma L 1220–1400; coxal shield L 780–950; Cx-I/II mL 210–280/150–190. Genital field L/W 200– 250/200–210; L Ac-1 64–75, L Ac-2 57–70, L Ac-3 35–45; genital flaps with ca 40 pairs of setae at medial margin, arranged in a single line on level of Ac-1–2, in double and triple lines near Ac-3.

Leg measurements (L/H, ratio): I-L-4 167–200/59–70, 2.77–2.96; I-L-5 187–223/48–58, 3.71–4.10; I-L-6 160–180/40–48, 3.68–4.00; IV-L-4 304–400/65–85, 4.18–5.11; IV-L-5 330–430/51–70, 6.00– 7.00; IV-L-6 293–344/48–60, 6.00–6.17; proportions of segments (L ratio): IV-L-4/5 0.92–0.94, IV-L- 4/6 1.03–1.13, IV-L-5/6 1.09–1.22; IV-L claw L 45–50.

Palp measurements (L/H, ratio, % total L): P-1 35–43/54–70, 0.61–0.65, 7–8%; P-2 130–175/78–100, 1.50–1.68, 27–29%; P-3 95–130/62–75, 1.54–1.73, 22%; P-4 150–193/50–59, 2.96–3.28, 33–34%; P-5 45–55/8–10, 5.50–6.25, 9–10%; proportions of segments (L ratio): P-2/P-3 1.22–1.40, P-2/P-4 0.80– 1.00, P-3/P-4 0.63–0.71; distance ratio distal setae P-3 (A/B) 0.68–1.71; P-4 ventral sectors 37–55%, 22–45%, 17–22%; dorsal/ventral L ratio 1.18–1.23; palp total L 465–588.

Females

Idiosoma L 1050–1600; coxal field L 850–1050; Cx-I/II mL 215–280/160–190. Genital field L/W 210– 290/190–230; L Ac-1 75–85, L Ac-2 65–80, L Ac-3 50–65; genital flaps with ca 25 pairs of setae at medial margin, arranged in a single line.

Leg measurements (L/H, ratio): I-L-4 187–211/64–75, 2.82–2.93; I-L-5 200–231/51–59, 3.64–4.09; I-L-6 165–180/44–51, 3.61–4.00; IV-L-4 341–400/66–81, 4.67–5.17; IV-L-5 352–444/55–64, 6.00– 7.00; IV-L-6 304–363/52–65, 4.77–6.31; proportions of segments (L ratio): IV-L-4/5 0.89–0.97, IV-L- 4/6 1.06–1.13, IV-L-5/6 1.16–1.22; IV-L claw L 43–55.

Palp measurements (L/H, ratio, % total L): P-1 33–40/63, 0.52–0.64, 6–7%; P-2 145–180/88–105, 1.49–1.65, 29%; P-3 110–145/66–79, 1.54–1.80, 22%; P-4 165–195/55–70, 2.75–3.08, 32–33%; P-5 50–53/8–10, 5.25–6.25, 9–10%; proportions of segments (L ratio): P-2/P-3 1.22–1.34, P-2/P-4 0.86– 0.92, P-3/P-4 0.65–0.74; distance ratio distal setae P-3 (A/B) 0.92–1.40; P-4 ventral sectors 37–55%, 34–38%, 17–27%; dorsal/ventral L ratio 1.17–1.19; palp total L 534–540.

Remarks

The name obscura was introduced as a “nov. var.” within the description of L. porosa for porosa -like specimens with dark blue green appendages ( Thor 1900: 273). Two figures ( Thor 1900: pl. 10 figs 3–4) show the venter of a male and a palp of a specimen of uncertain sex; no further diagnostic features were given by the author.

Lebertia obscura agrees with L. porosa in most morphological details, such as the shape of the coxal field, the swimming setation of legs, or the proportions of the palp segments and arrangement of their setae. The most striking difference is found in the formation of the hind leg segments, where L. porosa has distinctly stouter segments and longer claws. In addition to the difference in colouration (as highlighted in the original description, L. porosa with pale brown, not blue green appendages), our data also show that L. porosa has a higher number of setae along the medial margins of the genital flaps.

The designation of the specimen SMF 45040 as a “Cotype” is obviously erroneous (collected after the publishing date of the original description), but it fits the description given here except for the presence of seven strong ventral setae on IV-L-6. In other specimens, the number of these setae does not exceed five, and they are smaller in size. We cannot exclude that Thor was able to distinguish L. obscura from L. porosa on the base of colouration; the alteration of colours following the fixation of all available material does not allow consideration of this character at present. Among the eight specimens collected at the type locality on 20 Jul. 1898 and 13 Aug. 1901 and labelled “ Lebertia porosa + obscura ” by Sig Thor, none agrees with the diagnosis given above for L. porosa : seven show character combinations typical for L. obscura , and one male is similar to specimens defined as Lebertia porosa aggr. sp. A in our investigation, a species which is intermediate between L. porosa and L. obscura in IV-L proportions (see below).

Our data show a wide distribution of the species in Norway from the far south to Nordland County (65° N). In light of the new species characteristics described here, further research is needed to clarify the geographical distribution of L. obscura .

Figures

Fig. 8. Lebertia (Pilolebertia) obscura Thor, 1900, ♂ from the type locality. A. Coxal field. B. Palp. C. I-L. D. II-L. E. III-L. F. IV-L. Scale bars = 100 µm.