Sandracottus festivus (Illiger, 1801)

Hendrich, Lars & Brancucci, Michel, 2025, Revision of the Oriental and Australasian diving beetle genus Sandracottus Sharp, 1882 (Coleoptera, Dytiscidae, Dytiscinae), ZooKeys 1223, pp. 87-147 : 87-147

Sandracottus festivus (Illiger, 1801)

Figs 5 , 16 , 29 , 35 , 51

Dytiscus festivus Illiger, 1802: 166 . (type locality: “ Ostindien [“ East India ” = India and the Malayan Archipelago] ”.

Sandracottus festivus (Illiger, 1801): Sharp 1882: 686 (comb. nov.); Régimbart 1899: 334 (descr.); Zimmermann 1920: 234 (cat.); Vazirani 1969: 273 (descr., cat.); Ninje Gowda and Vijayan 1992: 29–32 (ecol.); Ghosh and Nilsson 2012: 18 (cat.); Ghosh and Hegde 2015: 73 (faun.); Sonali et al. 2022: 339 (faun.); Hájek and Nilsson 2024: 91; Sheth et al. 2024: 8, 20 (check list, faun., key).

Sandracottus mixtus (non Blanchard, 1843): Shankar et al. 2023: 455 (faun., misidentified, photo shows S. festivus ); Deb and Subramanian 2023: 10–15 (faun., misidentified, photo shows S. festivus ).

Type material.

Not examined.

Additional material.

(202 specimens): • China: 1 ex., “ Chine ”, “ Samml. A. Zimmermann ” ( ZSM). • India: 1 ex., “ Panjab and U Provinces VI-X India ”, “ RL Woglum coll. ” ( USNM); 2 exs., “ Mahableshnar W. Ghato [Ghatol, Rajastan], 5500 ft India ”, “ Coll´n J. D. Sherman Jr. 1926 ” ( USNM); 2 exs., “ INDIA – Tamil Nadu Road Salem – Yercaud Pond at 8–9 km from Yercaud – 1000 m 4. I. 1995 Mazzoldi P. leg. ” ( CPM); 9 exs., “ INDIA - Kerala m 700 – Road Thekkadi – Kottayam at 13 km from Thekkadi – Muddy pool 2. I. 1995 Mazzoldi P. leg. ” ( CPM); 6 exs., “ Aug. 43 Dehra Dun ” [Prov. Uttarakand, October 1943, Dehradun, Central Internment Camp for British India near Premnagar, 30 ° 20 N 78 ° 3 E] ( ZSM); 6 exs., “ Montagnes du Wynaad ”, “ Museum Paris ex Coll. R. Oberthur ” ( MNHN); 3 exs., “ Solan près Simla Lakhat 1896 ” ( NMB); 3 exs., “ Pulney Hills R. P. Castets 1898 ” ( MNHN); 4 exs., “ Maissour, Shinoga, Mai 1897 ” ( MNHN); 2 exs., “ Himalaya Simla ”, “ Coll. Franklin Müller ” ( DEI); 1 ex., “ Simla, IV-VII. 96 ”, “ Ex. Musaeo W. Rothschild 1899 ” ( MNHN); 3 exs., “ Bangalore, Silvepoore, G. Tabourel 1899 ” ( MNHN); 3 exs., “ Val de Kangra [Himachal Pradesh], Dharamsala, vers 1300 m, J. Berlioz, 1937 ” ( MNHN); 1 ex., “ Inde, Mont Abu, Tajputana, 1938, J. Berlioz Ex Musaeo Thorey ” ( MNHN); 1 ex., “ Calcutta, Ex. Museo E. Steinheil ” ( MNHN); 4 exs., “ Punjab, Simla, E. C. Ansorge B. M. 1922-455 ” ( NHMUK); 1 ex., “ Bangalore, Mysore 95-28 ” ( NHMUK); 5 exs., “ N. W. India 8438 ” ( NHMUK); 1 ex., “ Simla, Coll. Plason ” ( NMW); 1 ex., “ South India, Salem District, IX. 1943, P. S. Nathan leg. ” ( MNHN); 1 ex., “ South India, Coimbatore, 24. VIII. 1937, P. S. Nathan leg. ” ( MNHN); 1 ex., “ India (M. P.) Jabalpur district Lamhetghat village 28. III. 1962, R. G. Sharna leg. ”, “ Zoological Survey of India Central R. S. Lot No. 29 / 63 F. C. No. 362 ” ( NMB); 1 ex., “ Parasnath Hills & Panchi Survey ”, “ IV. 1918 Sinha & Nath ” ( NMB); 1 ex., “ India ” ( MNHN); 1 ex., “ Coimbatore Inde merid. IX. 1933 ” ( MNHN); 3 exs., “ Wagrar-Karur env. de Bellary, 1883, Chaper & de Morgan ” ( MNHN); 6 exs., “ Mahé Malabar ” ( MNHN); 3 exs., “ Côte de Malabar, T. Deschamps 1900 ” ( NMB); 1 ex., “ Orissa, Jaipur-Keonjahn Distr. Daitari, 29. XI. 1967, collected from water, Gy Topal ” ( NMB); 1 ex., “ Madhya Pradesh, Jablpur Dagmaga, 31. V. 1965, H. P. Agywal leg. ” ( CGW); 1 ex., “ India or. ” ( CGW); 1 ex., “ Karnataka, Western Ghats Mts., 30 km SEE Bhatkal, Kollur env., 26. - 28. V. 2006, V. Ryjacek ” ( NMPC); 1 ex., “ Tamil Nadu, Nilgiri Hills, Kunchappanai, 15 km SE Kotagiri, 900 m, 11 ° 2 ' N 76 ° 56 ' E, 13. - 20. V. 1994, Z. Kejval leg. ” ( NMPC); 2 exs., “ Rajasthan, Mt. Abu env., 100 km W Udaipur, 1150 m, 24 ° 35.35 ' N 72 ° 42.72 ' E, 24. - 27. VIII. 2002, P. Sipek & M. Fikacek leg. ” ( NMPC); 1 ex., “ Ostindien Coll. C. Felsche Geschenk 1907 ” ( SMTD); 1 ex., “ India or. post. ”, “ Coll. Maerkel ” ( SMTD); 1 ex., “ Madras, Coimbatore, 1400 feet, X. 1964, P. S. Nathan leg. ” ( ZSM); 2 exs., “ India or. ” ( ZSM); 1 ex., “ Indien, Tanquelar ” ( ZSM); 2 exs., “ Sammlung Cl. Müller ” ( ZSM); 2 exs., “ S-India, Kerala, Theimala nr. Shenkottah (70 km N Trivandrum) 150 m, 8 ° 57 ' N 77 ° 01 ' E, 5. IV. 1997, Schintlmeister & Siniaev leg. ” ( CLH); 1 ex., “ S India Rippon coll. ” ( CLH); 2 exs., “ Khasi Hills ” ( NHMUK); 1 ex., “ Ranikhet, Kumaon, H. G. C., H. G. Champion Coll. B. M. 1953-156 ” ( NHMUK); 10 exs., “ W. Almora Division, Kumaon, U. P. H. G. C., H. G. Champion Coll. B. M. 1953-156 ” ( NHMUK); 2 exs., “ W. Almora Division, Kumaon, U. P., I. 1920 ”, “ H. G. Champion Coll. B. M. 1953-156 ” ( NHMUK); 2 exs., “ W. Almora Division, Kumaon, U. P., IV. 1917 ”, “ H. G. Champion Coll. B. M. 1953-156 ” ( NHMUK); 8 exs., “ India, Orissa, Jajpur-Keonjahr, District Daitari, No. 975, netted from water, 29. XI. 1967, leg. Gy Topál ” ( TDMB); 1 ex., “ Rhimtal, 25. IX. 1979, Smetacek ” ( NMB); 1 ex., “ Rhimtal, 2. VIII. 1973, Smetacek ” ( NMB); 1 ex., “ S-India, Kerala, 15 km SW Munnar, Kallar Valley, 9. V. 1997, 1250 m, 10 ° 02 ' N 76 ° 58 ' E, Dembicky & Pacholatko leg. ” ( NMB); 1 ex., “ Tamil Nadu, Nilgiris, 15 km SE of Kotagiri, Kunchappanai, 900 m, 11 ° 22 ’ N 76 ° 56 ’ E, 7. – 22. V. 2000, leg. D. Hauck ” ( CJS); 1 ex., “ Tamil Nadu, Nilgiri Hills, 11 km SE Kotagiri, 1100 m, E Kunchappanai, 11 ° 24 ' N 76 ° 56 ' E, 3. - 15. V. 2002, P. Pacholatko leg. ” ( NMB); 1 ex., “ Southern Madhya Pradesh Hoshangabad District Pagara – Panchmarhi road, ca. 5 km NNE Panchmarhi, Panar Pani [stream], 850 m a. s. l. 22 ° 30 ' 25 " N / 78 ° 26 ' 43 " E, 26. + 27. II. 2008 M. Jäch leg. (Loc. MP 6) ” ( NMW); 2 exs., “ Nilghiri ”, “ Coll. Kraatz Régimbart det. ”, “ Sandracottus festivus Illiger ”, “ Zimmermann det. ” ( DEI); 1 ex., “ Calcutta ” ( NHMUK). • Nepal: 1 ex., “ Nepal 02. 08. 1981 Khare 1600 Beron ” ( CHF); 1 ex., “ Dhading distr., Thorpu bis Kordunje, 1300–1400 m, 24. VII. 1983, Martens & Schawaller leg. ” ( NMB); 2 exs., “ W Nepal, Kali Gandaki Khola Bhakta B. Tatopani 1100–1400 m, 12. - 14. V. 1984 ” ( NMB); 1 ex., “ Himalaya ” ( RMNH); 3 exs., “ S Dhaulagiri, W Beni Darbang, 1150 m, 1. XII. 2000, G. Riepl leg. ” ( NMW). • Bhutan: 2 exs., “ Bhakta B., Beguna, 2730 m, 24. VIII. 1976 ” ( NMB). • Sri Lanka: 3 exs., “ Belihul-Oya Ceylon 2 de trim. 89 I. Z. Kannegieter ”, “ Muséum Paris, Coll. R. Oberthür ” ( MNHN, CLH); 1 ex., “ Ceylon ”, “ W Robinson bequest 1929 ” ( USNM); 2 exs., “ Ceylon N. P. Madugoda 15. IX. 1953, F. Keiser ” ( NMB); 1 ex., “ Museum Paris Inde Bellary du Ceylan de Morgan 1896 ” ( MNHN); 1 ex., “ Kandy, Ceylon H. Rolle, Berlin, SW ”, “ coll. Gärtner ” ( DEI); 1 ex., “ Süd Ceylon Mai 1889 H. Fruhstorfer ”, “ Coll. Kraatz Régimbart det. ”, “ Hydat. festivus ”, “ Zimmermann det. ” ( DEI); 15 exs., “ Nalanda Ceylon W. Horn 1899 ”, “ Zimmermann det. ” ( DEI); 3 exs., “ Paradna W. Horn 1899 ”, “ Sandracottus festivus Illig, Zimmermann det. ” ( DEI); 11 exs., “ Ceylon Kannegieter 1889 ” ( MNHN); 3 exs., “ Ceylon Nalanda 2 e trim. 89 I. Z. Kannegieter ” ( MNHN); 1 ex., “ Ceylon, Belihul-Oya, 2 e trim. 89, I. Z. Kannegieter ” ( MNHN); 1 ex., “ Ceylan, Deschamps, 1889 ” ( MNHN); 4 exs., “ Kandy, IX-XII. 1897, E. E. Green, 1917-54 ” ( NHMUK); 2 exs., “ Kelani Valley nr. Colombo W. Braine 1910-283 ” ( NHMUK); 4 exs., “ Ceylon G. Lewis 1910-320 ” ( NHMUK); 1 ex., “ Ceylon, 1891 Heuser leg. ” ( NMW); 1 ex., “ Kandy X. 1907 H. E. Andrewes Bequest B. M. 1922-221 ” ( NHMUK); 1 ex., “ Kandy, 20. II. 1902 Dr. Uzel leg. ” ( NMW); 6 exs., “ Haputale env., Beragala, 9. XII. 1980, M. Jäch leg. ” ( CGW, NMW); 2 exs., “ Dambulla env. 300 m 19. IV. - 9. V. 1991 J. Kolibac leg. ” ( NMB); 1 ex., “ Habarana 10. XI. 1982 G. Duranton leg. ” ( NMB); 1 ex., “ Sigiriya 10. XI. 1982 G. Duranton leg. ” ( NMB); 1 ex., “ Anuradkapura 3. XI. 1982 G. Duranton ” ( NMB); 1 ex., “ Paradina 1899 W. Horn ” ( ZSM); 1 ex. “ Matale Ceylon 1899 leg. W. Horn ” ( ZSM); 1 ex., “ Ceylon Madarász Madatugama 21. II. 1896 ”, “ Sandracottus festivus Illiger Guignot det. 1956 ” ( TDMB); 9 exs., “ Sri Lanka Moneragala Kumaradola group X. 1997 M. M. Bahir & S. V. Nanayakkara leg. ” ( CLH); 1 ex., “ Sri Lanka, Ratnapura Sincharaja rain forest, 17. - 19. II. 1997, Udovichenko leg. ” ( CLH). • Pakistan: 1 ex., “ Hazara, Balakot 900–1100 m, 3. - 7. VI. 1983, leg. Eckweiler ” ( NMB); 1 ex., “ Islamabad, 1 km S Hotel Adventure Inn, 500 m, 3. VII. 1998, leg. Gy. Fábian & B. Herczig ” ( TDMB); 1 ex., “ Pakistan, Kashmir, Himalaya Mts., 20 km S Muzaffarabad, Nara village, 73 ° 29 ' E, 34 ° 01 ' N, 750 m, 12. IX. 1997, leg. Gy. Fábian & G. Ronkay ” ( TDMB).

Country unknown.

1 ex., “ Novara Reise, 1857-1859 ” ( NMW).

Redescription.

Body broad oval, shiny, testaceous with black markings. Ventral side completely dark brown to black, legs testaceous, hind legs somewhat darker.

Head testaceous with posterior part and broadly so on posterior half alongside as well as two elongate spots on clypeus black, shiny (Figs 5 , 51 ). Surface almost smooth consisting of dense and very numerous punctures of different size and of larger, much sparser ones, particularly numerous on frons. Clypeal grooves, punctures alongside eyes and transverse depression beside eyes distinctly impressed, punctures large and coalescent. Antennae testaceous; antennomeres slender, antennomere V 4.5 × as long as broad.

Pronotum testaceous with median black marking reaching from posterior to anterior margins; long and broad on posterior, distinctly shorter and narrower on anterior margin and strongly constricted on middle (Figs 5 , 51 ). Surface very superficially shagreened, almost not discernible, with dense punctation; punctures medium-sized mixed with smaller ones. Anterior and lateral puncture lines dense and coalescent, punctures becoming sparse towards middle and lacking in very middle of anterior margin. Posterior puncture line with coarse and coalescent punctures on middle of each side, distinctly smaller and spaced on disc.

Elytra testaceous to ferrugineus brown with black markings consisting of three transverse bands (Figs 5 , 51 ); particularly characterised by presence of a longitudinal testaceous subsutural spot on anterior third. Epipleura testaceous to ferrugineus brown. Surface very slightly and superficially shagreened and covered with double punctation, a smaller and denser one as well as a larger one that is more sparsely distributed. Puncture lines with groups of medium-sized punctures mostly grouped by 5–6 punctures; groups closer together on discal row.

Ventral side dark brown. Legs, particularly fore and mid legs testaceous, hind legs ferrugineus brown to dark brown. Prosternal process short and broad, 1.5 × longer than broad, flattened finely but distinctly sculptured; posterior margin broadly rounded. Whole surface very superficially shagreened and finely punctured. Metatibia with sparse medium-sized punctures on outer half. Ventrites II – VI very superficially shagreened, slightly and longitudinally wrinkled on lateral parts, whole surface densely covered with very small punctures and larger sparser ones. Posterior margins rounded, bordered with some large and coalescent punctures on middle of each side.

Measurements: TL = 14.7–15.5 mm, TL-h = 13.5–14.4 mm, TW = 8.0– 8.8 mm.

♂. Protarsomeres I – III strongly enlarged with three larger suckers and numerous smaller one. 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. 16 a ). Parameres broad and pointed at apex (Fig. 16 b ).

♀. Similar to male, tarsi not enlarged. Microsculpture on ventrite VI as in male.

Distribution.

India: Andhra Pradesh, Arunachal Pradesh, Assam, Himachal Pradesh, Jharkhand, Madhya Pradesh, Maharashtra, Orissa, Punjab, and Tamil Nadu ( Ghosh and Nilsson 2012; Deb and Subramanian 2023; Sheth et al. 2024); Pakistan, Nepal, Bhutan, Sri Lanka (Fig. 29 ). Specimens were collected between 150 and 2700 m above sea level. Zeng (1989) in his doctoral thesis recorded S. festivus from numerous provinces in southern China (see also Nilsson 1995). However, revision of Zeng’s specimens revealed that he misidentified S. festivus and S. mixtus [ = hunteri ] (S. Zhao, in litt. 2020). The single historical specimen from China deposited in ZSM is probably mislabelled. For now, we consider S. festivus as not occurring in China.

Differential diagnosis.

The dorsal colour pattern of the Indian S. festivus is near to the Indonesian S. chevrolati but can be easily separated by its consistently larger size (TL = 14.7–15.5 mm, S. chevrolati : TL = 10.0– 13.5 mm) (Figs 5 , 51 ), its distributional range (Figs 25 , 29 ), and shape of median lobe and parameres (Figs 14 a, b , 16 a, b ).

Habitat.

In India, Pakistan, and Sri Lanka the species is collected from protected embayments of slow flowing forest streams, ponds, swamps, and artificial water tanks, often rich in aquatic vegetation. At Panar Pani [stream] in broad but slow flowing forest stream (ca 3–5 m wide), with its bottom consisting of gravel and rocks (Fig. 35 ). Together with the Indian S. dejeanii and the two subspecies of the Australian S. bakewellii , this species is not restricted to densely forested areas as many other species of the genus, especially in SE Asia. Ninje Gowda and Vijayan (1992) have published their research results on the predatory behaviour of the species on mosquito larvae in sewage tanks. The species is capable to flight and was attracted to light.

Figures

Figure 25. Distribution of Sandracottus chevrolati in Indonesia.

Figure 29. Distribution of Sandracottus festivus [black dots] and S. jaechi [red square] in the Indian subcontinent.

Figures 4–7. Habitus of 4 Sandracottus dejeanii (South India) 5 S. festivus (Sri Lanka) 6 S. femoralis (Papua New Guinea, Rigo) 7 S. hunteri (Thailand).

Figures 16–19. Median lobe of aedeagus in ventral view (a), and right paramere in lateral view (b): 16 Sandracottus festivus 17 S. femoralis 18 S. hunteri and 19 S. insignis.

Figures 31–36. Habitats of Sandracottus 31 Australia, Northern Territory, 50 km S Adelaide River, creek at Scenic Route (NT 9) and 32 South Queensland, Winfield, Winfield Road, rest pool (QLD 54), habitats of S. bakewellii bakewellii (photos: L. Hendrich) 33 Northern Territory, Ormiston Gorge, habitat of S. bakewellii guttatus (photo: M. Baehr) 34 Pakistan, Sistan va Baluchestan Prov., Pir Sohrab env., rest pool in wadi, habitat of S. dejeanii (photo: J. Hájek) 35 India, southern Madhya Pradesh, Hoshangabad District, Pagara – Pachmarhi road, ca 5 km NNE Panchmarhi, Panar Pani, habitat of S. dejeanii and S. festivus (photo: M. Jäch) 36 Indonesia, Irian Jaya, Nabire, Nabire-Ilaga track, km 62, habitat of S. femoralis (photo: L. Hendrich).

Figures 50–53. Habitus of 50 Sandracottus dejeanii (India, Himachal Pradesh, Kangra Valley, Dharamsala) 51 S. festivus (Sri Lanka, Ratnapura, Sincharaja 52 S. femoralis (Indonesia, West Papua, Kapupaten Paniai, Nabire) 53 S. hunteri (China, Central Sichuan).

Figures 12–15. Median lobe of aedeagus in ventral view (a), and right paramere in lateral view (b) 12 Sandracottus bakewellii bakewellii 13 S. bizonatus 14 S. chevrolati and 15 S. dejeanii.