Sandracottus femoralis Heller 1934
Creators: name: Hendrich, Lars
name: Brancucci, Michel
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Dytiscidae
Sandracottus
Sandracottus femoralis

description: Sandracottus femoralis Heller, 1934
Figs 6, 17, 27, 36, 52
Dytiscus flavocinctus Guérin-Méneville, 1830: 61 (type locality Manokwari, West Papua, Indonesia); Boisduval, 1835: 49 (preoccupied by Hummel 1823 and objective synonym of Sandracottus guerini); Boisduval, 1835: 49 (descr.).
Sandracottus flavocinctus (Guérin-Méneville, 1830): Régimbart 1899: 339 (descr.); Zimmermann 1920: 234 (cat.).
Sandracottus femoralis Heller, 1934 b: 3 (type locality: Buka, Solomon Islands); Alarie et al. 2023: 305 (larval descr.), idem: 320 (habitat); Hájek and Nilsson 2024: 91 (cat.).
Sandracottus guerini J. Balfour-Browne, 1939: 114, replacement name for Sandracottus flavocinctus; Hájek and Nilsson 2024: 91 (cat.) (syn. nov.).
Comments on classification.
Sandracottus femoralis was described from the Solomon Islands. We have studied Heller’s type specimen of S. femoralis, Guérin-Meneville’s type of D. flavocinctus, as well as numerous specimens of S. guerini over its complete range. There is no doubt that both taxa belong to the same species. Sandracottus guerini Balfour-Browne, 1939 is a replacement name for S. flavocinctus Guérin-Méneville but is more recent than Sandracottus femoralis, so the valid name for this species must be S. femoralis.
Type material
of Sandracottus femoralis. Holotype: Female, “ Buka Salomonen Juli 1930 ”, “ Coll. H. Hediger ”, “ 1933 8 ” [blue label], “ S. femoralis Typus ” [red label], “ Staatl. Museum für Tierkunde, Dresden ”, “ Sandracottus femoralis Heller, 1934 Hendrich & Brancucci det. 2006 ”. Examined.
Dytiscus flavocinctus: Lectotype (herewith designated): Female, “ Mus. Paris Nouv. Guninée Dumont d´Urv. 1841 ”, “ Dory [Manokwari] N. Guinee Duvelle Durville ” [Dumont d´Urville], [round handwritten label], “ Hidaticus [sic!] flavocinctus ” [handwritten label], “ Lectotypus Dytiscus flavocinctus Guérin-Men. des. M. Brancucci & L. Hendrich 2010 ” [red printed label], “ Sandracottus guerini B. - Br. Det. M. Brancucci L. Hendrich 10 ” [white printed label] (MNHN). Examined.
Additional material.
(118 specimens): • Indonesia: 1 ex., “ Indonesia: Halmahera Isl., Khao Dist., Camp 34 34 km inland from Pan-Tunggal Lumber Co. base camp at Tg. Loleo ”, “ 1-14 Feb. 1981 AC Messer & PM Taylor ” (USNM); 1 ex., “ Indonesia: Halmahera Isl., Jailolo Dist., Kampung Psir Putih 0 ° 53 ' N 127 ° 41 ' E ”, “ 1-14 Aug. 1981 PM Taylor ” (USNM); 13 exs., “ Indonesia: Halmahera Isl., Jailolo Dist., Kampung Psir Putih 0 ° 53 ' N 127 ° 41 ' E ”, “ 15–31 Jan. 1981 AC Messer & PM Taylor ” (USNM); 18 exs., “ Indonesia: Halmahera Isl., Jailolo Dist., Kampung Psir Putih 0 ° 53 ' N 127 ° 41 ' E ”, “ 1-14 May 1981 AC Messer & PM Taylor ” (USNM); 2 exs., “ Indonesia: Halmahera Isl., Jailolo Dist., Kampung Psir Putih 0 ° 53 ' N 127 ° 41 ' E ”, “ 14. Aug. 1981 PM Taylor ” (USNM); 1 ex., “ Batanta Island [Pulau Batanta], Arefi, 2004, A. Skale leg. ” (CAS); 1 ex., “ Bernstein Morotai ”, “ flavocinctus Aubé ” (MNHN); 1 ex., “ Aru Insel ”, “ Samml. A. Zimmermann ” (ZSM); 1 ex., “ Rosenberg, Ins. Aru ” (RMNH); 1 ex., “ Key Insel ”, “ Samml. A. Zimmermann ” (ZSM); 2 exs., “ Bernstein, Morotai ” (RMNH); 1 ex., “ N. Moluccas, Bacan Island, Mt. Sibela, 400 m, 14 km SE Labuha, primary forest, 2–13. II. 1996, 0 ° 38´S Lat. 127 ° 32´E, leg. V. Siniaev & E. Afonin leg. ” (CLH); 2 exs., “ SE Moluccas Aru ISLS, WOKAM I. 17 km NE Wakua vill., 1–7 - II. 2022, St. Jakl leg. ” (CLH, NMPC); 8 exs., “ N Moluccas: Bacan, Wayaua, alt. m. 0050, 05. - 16. vii. 1985, J. Huijbregts ” (RMNH); 1 ex., “ Indonesia, Maluku, Obi Isl., South coast, 22 km N of Tapaya vill., Seribu Mts., 1200–1500 m, S. Jákl leg., 20. xi- 10. xii. 2008 ” (NMPC); 3 exs., “ Indonesia, Papua Dekai, upper Brazza, 273 m, 2. / 3. vi. 2015, - 4.74108472466468 139.654211075976, Sumoked (Pap 044) ” (MZB, ZSM); 2 exs., “ Indonesia Papua Barat, Kebar, shaded deep sandy irrigation roadside ditches, 584 m, 6. xi. 2013, - 0.80775253 133.05923529, UNIPA (BH 031) ” (ZSM); 4 exs., “ Irian Jaya, Nabire, Nabire-Ilaga track, km 62, 250 m, 24. VII. 1991, M. Balke & L. Hendrich leg. (IR 22) ” (CLH, NMW); 1 ex., “ Tami River Hollandia 1930 R. Voorhoeve leg. ” (CLH); 1 ex., “ Seram, E Wahai, 12. II. 1989, M. Jäch ” (NMW); 1 ex., “ New Guinea, Wareo, 1933 ” (ZSM); 6 exs., “ Dutch New Guinea: Humboldt Bay Dist. Pukusam Dist. West of Tami River vi. 1937 ”, “ B. M. Nat. Hist. London ” (CLH, NHMUK). • Papua New Guinea: 1 ex., “ Nouvelle Guinée ” (MNHN); 1 ex., “ New Guinea, NE Zenag-Lae, 200 m, 16. I. 1979 ” (NMB); 10 exs., “ N. Guinea mer. Rigo Lugio 1889 L. Loria ” (MNHN, RMNH); 5 exs., “ N. Guinea mer. Rigo VII. 1889 L. Loria ” (MNHN, NMW); 1 ex., “ Morobe Prov. Wau, 1200 m 1. - 15. V. 1962 light trap J. Sedlacek leg. ” (NMW); 1 ex., “ Morobe Prov. Bulolo 700 m 9. XI. 1962 J. & M. Sedlacek leg. ” (NMW); 1 ex., “ Morobe Kilolo Creek 7 km W Wau 1070 m 15. - 21. I. 1969 J. Sedlacek leg. ” (NMW); 1 ex., “ Morobe Prov. Garaina 700 m 21. III. 1998 A. Riedel leg. ” (NMW); 1 ex., “ Morobe Prov. Wau 15. XII. 1968 H. Ohlmus leg. ” (ANIC); 6 exs., “ Madang Prov. Batabag village 50 m XI. - XII. 2000 5 ° 08 ' S 145 ° 46 ' E L. Cizek leg. ” (NMB); 1 ex., “ Madang Alexishafen, sago swamp, 22. V. 1991, D. J. Larson leg. ” (ANIC); 6 exs., “ Madang, Nagada River near Nobanob, 12. VI. 1991, D. J. Larson leg. ” (ANIC, QM); 1 ex., “ New Guinea Biro 96 Friedrich-Wilhelmshafen ” (TDMB). • Solomon Islands: 1 ex., “ Solomon Islands: New Georgia, 2 mls. W. Of Lamberte 1. IX. 65. Roy. Soc. Exped. B. M. 1966-1 ”, “ bomb crater pool, coast road ” (NHMUK); 3 exs. (+ numerous larvae), “ SOLOMON ISLANDS, GUADALCANAL, ca. 3.5 km SE of BARANA vill., (drying up stream in shaded gorge), 09 ° 29.8 ' S, 159 ° 59.5 ' E; 190 m, 24. xi. - 14. xii. 2013, Jiří Hájek leg. ” (NMPC); 3 exs., “ South Pacific, Solomon Is. GUADALCANAL I., 500–650 m Koso vill. Env., ca. 15–18 km SSE of Honiara, 1–18. XII. 2016 St. Jakl leg. ” (CLH).
Redescription.
Body broadly oval, submatt / slightly shiny, black with ferrugineus brown markings. Ventral side completely dark brown to black, legs testaceous, hind legs somewhat darker.
Head testaceous with posterior part broadly black leaving free two small testaceous spots on vertex (Figs 6, 52). Surface submatt, shagreened, consisting of dense and minute punctures not very uniform in size and of larger and much sparser ones, more numerous on frons. Clypeal grooves and punctures alongside eyes marked, punctures medium-sized but coalescent. Antennae testaceous; antennomeres slender, antennomere V 4 × as long as broad.
Pronotum black with lateral margins ferrugineus brown, and narrow, testaceous, horizontal band, interrupted medially (Figs 6, 52). Surface submatt, distinctly shagreened, with very dense punctation; punctures medium-sized and distant of only 1–2 × their own diameter. Anterior puncture line interrupted in middle; punctures relatively small but coalescent, forming wrinkles and becoming sparse medially and lacking in mid-length of anterior margin. Posterior puncture line with coarse and coalescent punctures in middle of each side, forming distinct wrinkles, distinctly smaller and spaced on disc.
Elytra black with small testaceous markings consisting of basal band sometimes reduced to different small spots at base, one postmedian spot, one preapical short and reduced band, and an apical spot (Figs 6, 52), submatt. Epipleura ferrugineus brown. Surface distinctly shagreened and covered with small and dense punctures as well as with larger and much sparser ones. Puncture lines with groups of medium-sized punctures mostly grouped in five or six punctures, groups closer together on discal line. Sutural puncture line marked only by few punctures on apical part.
Ventral side dark brown. Legs, particularly fore and mid legs testaceous, hind legs ferrugineus brown to dark brown. Prosternal process short and broad, 1.3 × longer than broad, flattened, finely but distinctly sculptured; posterior margin broadly rounded. Metatibia with sparse medium-sized punctures on whole surface. Ventrites II – VI very superficially shagreened, slightly and longitudinally wrinkled on lateral parts, densely covered with very small punctures and larger sparser ones. Posterior margins rounded, deeply bordered with some large and coalescent punctures in middle of each side along margin.
Measurements: TL = 11.9–12.6 mm, TL-h = 11.0– 12.8 mm, TW = 7.0– 7.5 mm.
♂. Protarsomeres I – III strongly enlarged with three larger suckers and numerous smaller ones. Mesotarsomeres I – III with two rows of small suckers. Median lobe of aedeagus, in ventral view, broad, parallel-sided up to apex, here slightly broadened and broadly rounded (Fig. 17 a). Parameres broad and pointed at apex (Fig. 17 b).
♀. Similar to male, tarsi not enlarged. Microsculpture on ventrite VI as in male.
Differential diagnosis.
The combination of size and dorsal colour pattern (Figs 6, 52) separates S. femoralis from all other species of the genus. The very similarly coloured S. maculatus is always larger (TL = 14.0– 16.1 mm) and more broadly oval than S. femoralis (TL = 11.9–12.6 mm). Furthermore, S. femoralis can be separated from all other species of the genus by the shape of the median lobe and parameres (Fig. 17 a, b). All instar larvae were described by Alarie et al. (2023).
Distribution.
Indonesia: Moluccas (Bacan, Batanta, Halmahera, Obi, Seram, Morotai), Key and Aru Islands, and West Papua; Papua New Guinea up to the Solomon Islands (Fig. 27).
Habitat.
In West Papua specimens were collected in small but mainly exposed primary rainforest pools and puddles, always enriched with decaying leaves (Fig. 36). On Bacan Island also collected at light. On the Solomon Islands found in an old water-filled bomb crater near a coastal road (New Georgia), and a pool formed by the drying up of a stream on a clay bed, covered with decaying leaves and twigs (Guadalcanal; Alarie et al. 2023: 320). Sandracottus femoralis is distributed from lowland forest up to hilly mountain rain forests at ~ 1200 m altitude.
description: Published as part of Hendrich, Lars & Brancucci, Michel, 2025, Revision of the Oriental and Australasian diving beetle genus Sandracottus Sharp, 1882 (Coleoptera, Dytiscidae, Dytiscinae), pp. 87-147 in ZooKeys 1223 on pages 87-147, DOI: 10.3897/zookeys.1223.138220