Thunberga nossibeensis Jäger 2020, comb. nov.
Creators: name: Jäger, Peter
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Sparassidae
Thunberga
Thunberga nossibeensis

description: Thunberga nossibeensis (Strand, 1907) comb. nov.
Figs 1–16, 32–37, 47
Olios nossibeensis Strand, 1907: 557 (description of female; holotype female from Nossibé [=Nosy Be in Antsiranana Province, S 13°19’51’’, E 48°16’59’’, 100 m elevation], female paratype (s) from Fort Dauphin [=Tolognaro in Toliara Province, S 25°1’5.27’’, E 46°58’27.01’’, 15 m elevation], Vorkamp leg., Museum Lübeck, presumably lost; see Nentwig et al. 2020). Strand 1916 (description of male; 1 male [PJ 730], Madagascar, A. Stumpff leg. 18 December 1885, SMF 4694, examined). Jäger & Kunz 2005: 170, figs 72–78 (illustration of male).
Rhitymna hildebrandti Järvi, 1912: 54, fig. 47, pl. 4, figs 1–3 (description of female; 2 female syntypes [PJ 865, 866], NW Madagascar, Hildebrandt leg., ZMB 3718; examined). Jäger & Kunz 2005: 167, figs 79–85 (illustration of female). Järvi 1914: 169 (redescription of female). Syn. nov.
Additional material examined. MADAGASCAR: 1 female (PJ 3694), sub: Olios nossibeensis Strand (MNHN 1650-263 [2?]05). Mahajanga Province: 1 female (PJ 3693), Majunga [= Mahajanga, S 15°40’56’’, E 46°21’20.73’’, 14 m elevation], (MNHN 1650-1416 c. St.). Antananarivo Province: 1 male (PJ 3678), Bezavona [S 19°4’2.83’’, E 47°53’33.50’’, 1420 m elevation], K.L. Koch leg. 1953 (SMF). 1 subadult male, 1 subadult 1 female, 1 immature, with data as for previous male, 10 December 1885 (SMF 4683). Toamasina Province: 1 female (PJ 3695), Ambohivongy [close to Maroansetra, S 15°25’44’’, E 49°43’48’’, 10 m elevation], J. Millot leg. 1946 (SMF). 1 female (PJ 3679), 1 subadult female, 179 juv., egg sac with plant part, St. Marie [ca. 16°53’39.91”S, 49°54’21.39”E, 60 m], Voeltzkow leg. August 1904, Formol (ZMB). 1 female (PJ 3689), St. Marie [see above] (MNHN 19484). 1 female (PJ 3696), Ombila south of Tamatave [ca. 18°18’59’’S, 49°20’50’’E, 13 m elevation], littoral forest, R. Decary leg. 3 May 1928 (MNHN). 1 male (PJ 3698), Tamatave [= Toamasina, S 18°8’17’’, E 49°21’32’’, 20 m elevation], Walter Kaudern leg. February 1912 (NHRS). 1 female (PJ 3699), Fanrarazana [16°44’59’’S, 49°42’59’’E, 6 m elevation], Walter Kaudern leg. (NHRS). 1 male (PJ 3700), Fenerive [=Fenoariva, 17°22’36’’S, 49°23’54’’E, 30 m elevation], Walter Kaudern leg. 29 December 1911 (NHRS). Toliara Province: 1 male (PJ 3692), Fort Dauphin [= Tolognaro, S 25°1’5.27’’, E 46°58’27.01’’, 15 m elevation], Grandidier 146-97 (MNHN).
Diagnosis. Medium sized to very large spiders (body length of males: 15.5–24.0, females: 21.3–31.0). Males recognisable by their long and apically filiform embolus with its tip situated close to cymbium tip embedded in dense setae (also known from four conductor-less Pseudopoda species in Myanmar, Jäger 2015) (Figs 1–3). Females recognised by the very long and narrow median septum anteriorly and by the short but distinctly recognisable posteriad glandular appendages (Figs 8–11).
Description. Male (SMF from Bezavona): PL 10.7, PW 10.0, AW 4.9, OL 13.3, OW 6.6. Eyes: AME 0.60, ALE 0.51, PME 0.41, PLE 0.55, AME–AME 0.36, AME–ALE 0.17, PME–PME 0.79, PME–PLE 0.71, AME–PME 0.47, ALE–PLE 0.40, clypeus height at AME 0.56, clypeus height at ALE 0.47. Cheliceral furrow with 3 promarginal, 7 retromarginal teeth, and 45 denticles, most in patch close to promarginal teeth, distal row of 4 teeth (Fig. 5). Retromargin of chelicerae close to fang base with 3–4 bristles. Spination: Palp: 131, 001, 2111; legs: femur I–III 323, IV 321; patella I–III 101, IV 100; tibia I–III 2226, IV 2126; metatarsus I–II 1014, III 2024, IV 3026. Metatarsi I–III with dense scopula, III with ventro-distal bristle embedded in scopula, IV with a disto-ventral semi-circular array of 8 setae and an additional double row of setae. Leg formula: 2143. Measurements of palp and legs: Palp 15.7 (4.6, 2.2, 3.5, -, 5.4), I 55.2 (15.1, 6.0, 16.3, 14.1, 3.7), II 60.7 (16.7, 6.2, 18.7, 15.3, 3.8), III 42.9 (12.5, 5.0, 12.1, 10.3, 3.0), IV 45.7 (12.8, 4.4, 12.8, 12.2, 3.5).
Palp as in diagnosis (Figs 1–3). RTA broad proximally and slightly pointed distally, its ventral margin convex, dorsal margin almost straight. Cymbium longer than tibia, moderately bulging prolaterally, retrolateral margin undulating. Tegulum narrow, especially distally. Embolus arising at 9-o’clock-position from tegulum, running first distal and dorso-retrolateral into alveolus, then again distal. Conductor arising at 12-o’clock-position from tegulum, membranous, relatively compact. Spermophor moderately wide at retrolateral side of tegulum, bent at 90° in central tegulum.
Colouration (Figs 6–7, 32–34). Brown to light brown. Prosoma with distinct, longitudinal fovea. Chelicerae reddish-brown, frontally with longitudinal darker stripes (Figs 6, 34). Sternum, coxae light brown, gnathocoxae, labium reddish-brown, distally lighter. Legs brown, distally darker. Opisthosoma dorsally light brown with 2 pairs of muscle sigilla, otherwise without pattern; ventrally light brown with distinct irregular pattern of small patches.
Female (MNHN 19484 from St. Marie): PL 10.1, PW 9.3, AW 5.5, OL 11.8, OW 6.3. Eyes: AME 0.58, ALE 0.50, PME 0.46, PLE 0.54, AME–AME 0.39, AME–ALE 0.20, PME–PME 0.80, PME–PLE 0.65, AME–PME 0.56, ALE–PLE 0.46, clypeus height at AME 0.44, clypeus height at ALE 0.42. Cheliceral furrow with 3 promarginal, 5 retromarginal teeth, with 42 denticles in cheliceral furrow (Fig. 13). Retromargin of chelicerae close to fang base with 4–5 bristles. Spination: Palp: 131, 001, 2121, 1014; legs: femur I 323, II 323(2), III 323, IV 321; patella I–IV 101; tibia I 2126, II–IV 2026; metatarsus I–II 1014, III 2024, IV 3035. Leg formula: 2143. Measurements of palp and legs: Palp 14.3 (4.0, 2.0, 3.6, -, 4.7), I 40.6 (11.3, 5.1, 11.5, 10.0, 2.7), II 44.9 (12.8, 5.4, 13.0, 10.7, 3.0), III 33.8 (10.1, 4.1, 9.5, 7.6, 2.5), IV 35.7 (10.3, 4.0, 9.7, 9.0, 2.7). Metatarsus III with single ventro-distal bristle, embedded in scopula; IV with ventro-distal field of several bristles and a double row of bristles along metatarsus.
Copulatory organ as in diagnosis (Figs 8–11). Epigynal field roughly circular in posterior half with many muscle attachment points marginally, distinctly narrower anteriorly, anterior band-homologues in anterior third, posterior of them one pair of slit sensilla. Anterior pocket as wide as median septum posteriorly. Median septum over most of its length very narrow, broadened posteriorly with some transversal wrinkles. Internal duct system with first winding membranous and running a bit more than 360°, then running through another loop, before changing its direction and running posteriorly in direction to fertilisation ducts through the centre of the first winding. Glandular appendages together with central to anterior part sclerotised.
Colouration (Figs 35–37). Yellowish-brown. Prosoma dorsally with fovea and striae marked, with marbled line from ALE to margins at Coxae I. Chelicerae reddish-brown with distinct longitudinal stripes. Sternum, gnathocoxae, labium and ventral coxae yellowish brown without pattern. Legs yellowish-brown with indistinct spine patches on femora. Opisthosoma dorsally with 4 dark muscle sigilla, posterior pair darker, otherwise without distinct pattern, ventrally vividly and densely mottled; spinnerets light yellowish-brown.
Variation. Males (n=3) with PL 6.9–10.1, OL 8.6–11.7. Cheliceral furrow with 3 promarginal, 5–6 retromarginal teeth, and 28 denticles (n=1). Retromargin of chelicerae close to fang base with 3–5 bristles. Prosoma dorsally with shorter additional lines behind PLE and PME and medially, and with two patches in front of fovea. Ventral pattern on opisthosoma less distinct. Females (n=8) with PL 9.3–12.3, OL 11.5–19.2. Prosoma dorsally with two shorter additional marbled lines behind PLE and PME, respectively, some with a pair of dots in front of fovea. Chelicerae with 3 anterior, 5–6 retromarginal teeth, 34 denticles (n=1) and 3–5 bristles at fang base. Gnathocoxae in few specimens with diagonal dark line, labium and gnathocoxae darker, i.e. reddish-brown with distal end lighter. Sclerotised anterior parts of internal duct system more anteriad (not laterad as in types).
Distribution. Madagascar (Fig. 47: red circles).
Notes. Colouration of adults is in this species different from other congeners: the characteristic dotted lines on the dorsal shield of the prosoma are lacking, instead marbled lines running from ALE to the margin above coxa I or II are present. However, in the juvenile specimens the prosoma exhibits the typical dotted pattern and the chelicerae exhibit the longitudinal lines consisting of numerous small dots, whereas in subadult specimens these latter dots are fused to solid stripes and dots on the dorsal shield are reduced in number. Such colour pattern change is known from the genus Heteropoda Latreille 1804, when juveniles live in the leaf litter and adults for instance on tree bark. A similar shift during the ontogeny of the environment occupied might be also the reason in Thunberga nossibeensis comb. nov. It might be also one reason of the wider distribution range of this large species.
description: Published as part of Jäger, Peter, 2020, Thunberga gen. nov., a new genus of huntsman spiders from Madagascar (Araneae: Sparassidae: Heteropodinae), pp. 245-260 in Zootaxa 4790 (2) on pages 247-250, DOI: 10.11646/zootaxa.4790.2.3, http://zenodo.org/record/3889486