Meladema coriacea Laporte, 1835

Bilton, David T. & Ribera, Ignacio, 2017, A revision of Meladema diving beetles (Coleoptera, Dytiscidae), with the description of a new species from the central Mediterranean based on molecules and morphology, ZooKeys 702, pp. 45-112 : 50-65

Meladema coriacea Laporte, 1835 Figures 3A, 4A, 5A, 6A, 7A, C, 8A, C, 9, 10, 11A, 12A, E 13A, 14A, 15A, 16, 17, 18D, 19, 20 A–N, 23, 25C

Scutopterus coriaceus Dejean, 1833: 54, nomen nudum.

Meladema coriacea Laporte, 1835: 98 (partim); Sharp 1882: 631 (partim); Guignot 1932: 655 (partim); Gschwendtner 1936: 41 (partim); Guignot 1961: 769 (partim); Guéorguiev 1987: 127 (partim); Machado 1987: 60 (partim); Franciscolo 1979: 617 (partim);

Colymbetes coriaceus (Laporte, 1835): Aubé 1836: 94; Aubé 1838: 220 (partim); Wollaston 1865: 67 (partim).

Scutopterus coriaceus (Laporte, 1835): Wollaston 1871: 221 (partim).

Meladema coriaceum Laporte, 1835: Branden 1885: 95 (partim).

Notes.

Of these earlier works, only Aubé (1836) provides sufficient detail to demonstrate that he is referring to M. coriacea as redefined below. His description states: “entièrement couvertes de petites impressions demi-circulaires, plus profondes à la partie convexe; en avant elles sont assez bien isolées; en arrière elles sont un peu confondues", details which allow the separation of M. coriacea from M. lepidoptera sp. n. (see below).

Laporte’s original description (1835) could refer to either M. coricaea as redefined here, or M. lepidoptera sp. n., the only reference to the unique elytral sculpture of these beetles being "corps couvert de points très serrés, presque chagriné”. As discussed by Evenhuis (2012), attempts to locate types of material described by Laporte between 1828 and 1840 have almost always proved fruitless, and it is generally assumed that this material is lost or destroyed. It seems Laporte donated his early collection (pre-1840 material) to the forerunner of the Smithsonian Institution in January 1842, and that these collections have been lost in a subsequent fire ( Evenhuis 2012). As with other Laporte taxa, our attempts to locate the original type series of M coriacea have failed, no specimens being present in MNHN, despite Guignot (1961) suggesting that they may be located in this institution, nor in the BMNH or Melbourne Museum, Australia (S. Hinckley pers. comm.), the other two locations known to house some Laporte types ( Sharp 1901, Horn et al. 1990). As a consequence, and in accordance with article 75.3 of the ICZN (1999), we here designate a neotype for M. coriacea , in order to establish its taxonomic identity and precise usage of the name. Laporte’s original description cites "Midi de la France", a term used to describe a large part of the south of the country (not the centre, as suggested by Nilsson and Hájek, 2017a). All material we have genotyped, or examined, from southern France to date belongs to this same taxon.

Type locality.

"Midi de la France".

Type material.

Neotype ♀ (herein designated): "24/viii/2006 FRANCE Var// La Londe-les-Maures,// Vallon de Valcros, Les// Gaouby (ruines), pools in// Maravenne Torrent, 45m// P. Ponel leg." " 43°09'45.74"N 9°15'38.82"E " "DNA Voucher// NHM-IRM11C" " Meladema coriacea // Laporte, 1835// NEOTYPE// D T Bilton & I Ribera des. 2017" (NMW). Dry card mounted, tissue sample in ethanol and DNA aliquote, both with same data, retained in IBE. Sequence data from the neotype has been deposited in GenBank with accession numbers AF428207 (COI-3') and AF428189 (16S ribosomal RNA).

Additional material examined (genotyped specimens).

Algeria: 1 ♂ "24/viii/2006 ALGERIA// Aïn Damous 36 25.350N// 07 51.367E 523m V67// S. Bouzid leg." " Meladema // coriacea Laporte// Fery det. 2007" "DNA voucher// MNCN-HI6" (IBE); 1 ♀ "24/iii/2006 ALGERIA// Oued Bagrat V28// S. Bouzid leg." " Meladema // coriacea Laporte// Fery det. 2007" "DNA voucher// MNCN-HI4" (IBE). Chad: 1 ♀ "KOUDOU// VERS 2000 m.// 17 XI 49" "TIBESTI// MASSIF KOUSSI// PH. DE MIRÉ” “MUSÉUM PARIS" [blue label] "DNA voucher// IBE-AN739" (MNHN). France, mainland: 1 ♀ "24/viii/2006 FRANCE Var// La Londe-les-Maures,// Vallon de Valcros, Les// Gaouby (ruines), pools in// Maravenne Torrent, 45m// P. Ponel leg." " Meladema coriaceum // FRANCE, Dept. du Var.// La Londe-les-Maures,// Vallon de Valcros,// Les Gaouby (ruines),// pools in Maravenne// torrent, alto 45 m// 5 ix 99 P. Ponel" [HW] "DNA Voucher// NHM-IRM11A" (IBE); 1 ♀ "24/viii/2006 FRANCE Var// La Londe-les-Maures,// Vallon de Valcros, Les// Gaouby (ruines), pools in// Maravenne Torrent, 45m// P. Ponel leg." "DNA Voucher// NHM-IRM11B" (IBE). Italy, Sicily: 1 ♂ "SICILIA - PA// Bosco Ficuzzo// im beraio// 29.VII.88 le. M. ROMANO" [im beraio & date HW] "DNA voucher// IBE-AN691" (CTP). Malta: 1 ♀ "23/iv/2013 MALTA// between Mosta and L-Imtarfa// stony stream 35 53 60N// 14 24 14E A. Rudoy leg." "DNA voucher IBE-RA1064" (IBE). Morocco: 1 ♂ "17/vii/1997 MOROCCO// Tazzeka Nat. Park/ 4, ca.// 4 km tras desvío Cedral// I. Ribera leg." "DNA voucher// NHM-IRM1A" (IBE); 1 ♂ "17/vii/1997 MOROCCO// Tazzeka Nat. Park/ 4, ca.// 4 km tras desvío Cedral// I. Ribera leg." "DNA voucher// NHM-IRM1C" (IBE); 1 ♂ "2i/vii/1997 MOROCCO// Anti-Atlas, Oued Massa// I. Ribera leg." "DNA voucher// NHM-IRM2A" (IBE); 1 ♂ "2i/vii/1997 MOROCCO// Anti-Atlas, Oued Massa// I. Ribera leg." "DNA voucher// NHM-IRM2B" (IBE); 1 ex. "4 MOROCCO Taza 22.3.2008// mountain stream in Tazzeka N.P.// 1448m N34°03'09.2" W4°10'27.0" // Ribera, Hernando & Aguilera leg." "DNA Voucher// NHM-IR47" (IBE); 1 ex. "58 MOROCCO 19.4.2001// 30°47'507" N 7°31' 351"W // Tachokchte: Assif Siroua// c.1500 m I.Ribera & A.Cieslak leg." "DNA Voucher// NHM-IRM22a" (IBE); 1 ex. "58 MOROCCO 19.4.2001// 30°47'507" N 7°31' 351"W // Tachokchte: Assif Siroua// c.1500 m I.Ribera & A.Cieslak leg." "DNA Voucher// NHM-IRM22b" (IBE); 1 ex. "60 MOROCCO 21.4.2001// 30°39'456" N 9°21' 134"W // Immouzèr-des-Ida-Outanane // Assif Tanit, 550 m I. Ribera & A. Cieslak" "DNA Voucher// NHM-IRM21a" (IBE); 1 ex. "60 MOROCCO 21.4.2001// 30°39'456" N 9°21' 134"W // Immouzèr-des-Ida-Outanane // Assif Tanit, 550 m I. Ribera & A. Cieslak" "DNA Voucher// NHM-IRM21b" (IBE). Spain, mainland: 1 ♂, "1 ES Girona, Port Bou// Cami de la Riera, 28.6.2013// 42°25'34.5"N 3°8'9.3"E // 65m I.Ribera & A.Cieslak leg." "DNA Voucher// IBE-DV293" (IBE); 1 ex. "Tarragona// Corbera d’Ebre // r. Gaia 10.1.2004 I.Ribera" "DNA Voucher// MNCN-AI104"(IBE); 1 ♂, "3 ES Huesca 6km S Bernués // Bco. de Bernués 6.9.2013// 42°26'38"N 0°36'51"W // 690m I.Ribera & A.Cieslak leg" "DNA Voucher// IBE-DV292" (IBE); 1 ex. "1 ES Castellón, Ballestar// r. Sénia, pools upstr. reservoir// 500m N40°41'41" E0°13'25.5" // I. Ribera leg. 2.6.2006" "DNA Voucher// MNCN-AI860" (IBE); 1 ex. "1 ES Castellón, Ballestar// r. Sénia, pools upstr. reservoir// 500m N40°41'41" E0°13'25.5" // I. Ribera leg. 2.6.2006" "DNA Voucher// MNCN-AI861" (IBE); 1 ♂ "8 ES Cáceres, PN Monfragüe // Arroyo de Trasierra, G. del Fraile// N39°50'07.2" W6°06'02.6" 317 m// I.Ribera & P. Abellán leg. 13.6.2008" "DNA Voucher// IBE-DV291" (IBE); 1 ♂ "19/ix/1999 SPAIN Murcia// Fte. Caputa, Rio Mula// A. Millán leg." "DNA voucher NHM-IRM13a" (IBE); 1 ♂ "29/ix/1999 SPAIN Cordoba// Baena, Arroyo de las Beatas// 36 37 00N 04 20 00W// M. Baena leg." "DNA voucher// NHM-IRM14A" (IBE); 1 ♀ "29/ix/1999 SPAIN Cordoba// Baena, Arroyo de las Beatas// 36 37 00N 04 20 00W// M. Baena leg." "CColeopteraBA 9.99// M. BAENA" "DNA voucher// NHM-IRM14B" (IBE); 1 ♂ "29/ix/1999 SPAIN Cordoba// Baena, Arroyo de las Beatas// 36 37 00N 04 20 00W// M. Baena leg." "DNA voucher// NHM-IRM14C" (IBE); 1 ♀ "26/vii/1998 SPAIN Cadiz// Facinas// I. Ribera leg." "CADIZ 98// 10a" [HW] "DNA voucher// NHM-IRM10A" (IBE). Spain, Mallorca: 1 ex. "4 MALLORCA Mortixet// Rd. C710 tributary Te. Son March// I.Ribera & A.Cieslak 12.11.2000" DNA Voucher// NHM-IRM23a" (IBE); 1 ex. "4 MALLORCA Mortixet// Rd. C710 tributary Te. Son March// I.Ribera & A.Cieslak 12.11.2000" DNA Voucher// NHM-IRM23b" (IBE); 1 ex. "5 MALLORCA Els Casals// Rd. C710 Te. Son March// I.Ribera & A.Cieslak 12.11.2000" "DNA Voucher// NHM-IRM24a" (IBE). Spain, Canary Islands: 1 ex. "2 Gran Canaria 14.4.2001// S. Nicolas de Tolentino// Risco: bco. Guy Guy grande// I.Ribera & A.Cieslak leg." "DNA Voucher// NHM-IRM20a" (IBE); 1 ♀ "12/i/2000 Tenerife// Bco. Infierno 900m// coriacea " "DNA voucher// NHM-IRM18a" (CBP); 1 ♂ "14/i/2000 SPAIN Tenerife// Bco. de Masca// D. T. Bilton leg." "DNA voucher// NHM-IRM19A" (CBP); 1 ♂ "14/i/2000 SPAIN Tenerife// Bco. de Masca// D. T. Bilton leg." "DNA voucher// NHM-IRM19B" (CBP); 1 ex. "Tenerife, Chamorga// Bco. Roque Bermejo// 20.7.2006 A. Castro" "DNA Voucher// MNCN-AI1095" (IBE). Tunisia: 1 ♀ "13/iii/2005 TUNISIA// Cite el Morjne// 36 56 17.1N 8 47 29.8E// A. Castro leg." "Cite-el-Morjene// N36°56' 17.1// E8°47' 29.8 // 13-03-2005" reverse " Meladema " [HW] " MNCN AI-84// DNA spare ex." [HW] "DNA voucher// MNCN-AI84" (IBE). Turkey: 1 ♀ "26/vii/2014 TURKEY Izmir// 6 km E of Phoca, head of// reservoir 38 39 37.3N// 26 49 23.9E 40m// I. Ribera & A Cieslak leg." "TR 15" [HW] "DNA voucher// IBE-DV294" (IBE). All with " Meladema // coriacea Laporte, 1835// D T Bilton [or I Ribera] det. 2017".

Additional material examined (non-genotyped specimens). Algeria: 8 ♂♂, 15 ♀♀ "Algerie// Yakouren// J Dayren// VI.VII. 1909" “MUSÉUM PARIS// 1952// COLL R OBERTHUR" [blue label] (MNHN); 1 ♂, 1 ♀ "Algerie// Yakouren// J Dayren// VI.VII. 1909" “MUSÉUM PARIS// 1952// COLL R OBERTHUR" [blue label] " Meladema // coriaceum // Cast.// de. M. Brancucci ‘82” [Latin name, describer & '82 HW] (MNHN); 1 ♀ "Algerie// Yakouren// J Dayren// VI.VII. 1909" “MUSÉUM PARIS// 1952// COLL R OBERTHUR" [blue label] " Meladema // coriacea // Cast." [HW] (MNHN); 1 ♀ " Meladema // coriaceum // O. Kaïrous, Mouz.// 8 avríl 06" [HW] “MUSÉUM PARIS// Coll. P. de Peyerimhoff// 1950" (MNHN); 1 ♀ "O. Kaïrous // mouzaïa // 8 avríl 06" [HW] “MUSÉUM PARIS// Coll. P. de Peyerimhoff// 1950" (MNHN); 1 ♂ " Meladema // coriaceum // Djurdj. 9" [HW] “MUSÉUM PARIS// Coll. P. de Peyerimhoff// 1950" (MNHN); 1 ♂ "Djurdjura// 14.VIII.1947" [HW] “MUSÉUM PARIS// Coll. P. de Peyerimhoff// 1950" (MNHN); 1 ♀ “Aïn Takrarat// Mouzaïa // 28.VII.1934" [HW] “MUSÉUM PARIS// Coll. P. de Peyerimhoff// 1950" (MNHN); 1 ♂ "Oued In Dalay// Kouddu// Hoggar// 19.3.1925" [HW] “MUSÉUM PARIS// Coll. P. de Peyerimhoff// 1950" (MNHN); 1 ♂, 1 ♀ "Aguelmane// Sekkarasen// Hoggar 206// 29.3.1928" [HW] "MISSION DU// HOGGAR// FÉVRIER-MAI // 1928" “MUSÉUM PARIS// Coll. P. de Peyerimhoff// 1950" (MNHN); 1 ♂ "Oued Tinikert// Mt. Oudan, 1160// 16 avril 1928" [HW] "MISSION DU// HOGGAR// FÉVRIER-MAI // 1928" “MUSÉUM PARIS// Coll. P. de Peyerimhoff// 1950" (MNHN); 1 ♀ "Tassili des Ajjers// Gta. de Tikkal// 24 mars 1961" [HW] “MUSÉUM PARIS// Coll. P. de Peyerimhoff// 1950" (MNHN); 1 ♂ [green circle, illegible HW] " Meladema // coriaceum // Bône” [HW] (ISNB); 1 ♂ "C. coriaceus // Alger" [HW] "G. C. Champion Coll.// B. M. 1927-409" (BMNH); 1 ♂ "27// 95" "Setif.// Algerien" [HW] " Meladema // coriacea Lap.// det. H. Shaverdo 2015" [Latin name, describer & 15 HW] (NMW). Chad: 1 ♂ "KOUDOU// VERS 2000 m.// 17 XI 49" "TIBESTI// MASSIF KOUSSI// PH. DE MIRÉ” " Meladema // coriaceum Cast.// C. Legros det." [Latin name & describer HW] (MNHN); 2 ♀♀ "KOUDOU// VERS 2000 m.// 17 XI 49" "TIBESTI// MASSIF KOUSSI// PH. DE MIRÉ” (MNHN); 1 ♀ "Bassin de Gorrom// 2500m.// 24 déc. 1958" "TIBESTI// Emi Koussi// Bruneau de Miré” "DNA voucher// IBE-AN740" [not possible to amplify any DNA sequences] (MNHN); 1 ♀ "Tibesti// S. O du Kohoz// 2000m// 6.XI.49 Miré” [HW] “MUSÉUM PARIS// Coll. P. de Peyerimhoff// 1950" (MNHN). France, mainland: 1 ♂, 1 ♀ "S. France,// Cerbere.// C. Thomas &// R. L. Pocock.// 1900-215.// 18.IV.00" [date HW] (BMNH); 1 ♂ "S. France,// Cerbere.// C. Thomas &// R. L. Pocock.// 1900-215.// 18.IV.00" [date HW] " Scutopterus // coriaceus Aub," [HW] (BMNH); 1 ♀ "S. France,// Cerbere.// C. Thomas &// R. L. Pocock.// 1900-215.// 18.IV.00" [date HW] " Meladema // coriacea Cast.// C. R. Smith det. 1982" [Latin name, describer & 2 HW] (BMNH); 1 ♂, 3 ♀♀ " BANYULS// PYR. OR.// 12.8.1950" [12.8. HW] “BACHUFER” (NMW); 2 ♂♂, 1 ♀ "Banyuls s. Mer// 17.25 - V - 1951// F. G. Overlaet" "R, Mouchamps det.// Meladema coriacea Cast." [Latin name & describer HW] (ISNB); 1 ♂, 2 ♀♀ "Banyuls s. Mer// 17.25 - V - 1951// F. G. Overlaet" (ISNB); 1 ♂, 1 ♀ "21.8.84 France// Pyr. Or., ung. Banyuls// Bach Fery leg." [HW] "Mel.// coriacea // Cast. Fery det." [HW] (NMW); 1 ♂ "meladema// coriaceum " [HW] “Foix” [HW] "Coll. E. Dongé // Le Moult vendit" (ISNB); 1 ♂ "AVEYRON FR.// ST. ROME CERN.// VII-VIII 1940" "Coll. R. Van Dorsselaer" (ISNB); 1 ♀ “Provence” "Coll. P. Boppe// Le Moult vendit" (ISNB); 3 ♀♀ "France. 10.10.55.// Provence.// leg. Weygoldt. ’’ reverse "Coriaceum// Budberg" [HW] (NMW); 1 ♂ "Carcassonne// L. GAVOY" “♂” "MELADEMA// CORIACEUM// LAP." (ISNB); 1 ♀ "Carcassonne// Aude" [HW] "Ex. Coll. Bettinger" (ISNB); 1 ♀ “Toulon.” [HW] "Gallia// mer." "Collectio// Kaufmann" (NMW); 1 ♂, 2 ♀♀ "Toulon// S. Frankreich" reverse "A// 7598" [HW] (NMW); 1 ♂, 1 ♀ “Gard” [HW] "ex coll R P David// ex coll Peres Jesuites// (le moult vendit)" (ISNB); 1 ♂ "La Sauzette" " Meladema // coriaceum " [HW] (ISNB); 1 ♂ "St. Etienne Valléefranc. de// s// Rogerie" [HW - Villefranche de Rougerie?] "Coll. A. Fauvel" "Coriacea// Lap." [HW] (ISNB); 1 ♂ "CAUX// HERAULT// IX 1928" [IX & 8 HW] "Collection// Dr. Guignot" “♂” "Guignot det// MELADEMA// coriacea Cast." [Latin name & describer HW] (ISNB); 1 ♂ "CAUX// HERAULT// IX 1928" [8 HW] “♂” “MUSÉUM PARIS// 1960// Coll F. Guignot" " coriacea Cast." [HW] (MNHN); 2 ♀♀ "CAUX// HERAULT// IX 1928" [8 HW] “♀” “MUSÉUM PARIS// 1960// Coll F. Guignot" (MNHN); 2 ♂♂ "neffies// HERAULT// H. LAVAGNE" [neffies HW] “Coriaceum” [HW] "Ex Coll. Bettinger" (ISNB); 1 ♀ "St GUILHEM// HERAULT// H. LAVAGNE" “Coriaceum” [HW] "Ex. Coll. Bettinger" (ISNB); 1 ♀ " Meladema // coriaceum " [HW] "Montpellier// ( Hérault)” [HW] "Coll. E. Dongé // Le Moult vendit" (ISNB); 1 ♀ “Béziers // (Helt.)" [HW] "Coll. E. Dongé // Le Moult vendit" (ISNB); 2 ♂♂ “Lozère” [HW] " Meladema // coriaceum " [HW] "Coll. E. Dongé // Le Moult vendit" (ISNB); 2 ♂♂ “Lozère” [small, circular brown label, no text] "Coll. Odier.// B. M. 1921-288" (BMNH); 1 ♀ "♀// 5188" [HW] "Coll. R. I. Sc. N. B.// France Marseille// Coll. Fairmaire// Coll. L. Pandellé” [Marseille & Coll. Fairmaire HW] "Coll. A. Fauvel// (ex. coll. Pandellé)// Meladema // coriacea Lap.// R.I.Sc.N.B. 17.819" [Latin name & describer HW] (ISNB); 1 ♀ “♀” [HW] "Coll. R. I. Sc. N. B.// France Marseille// Coll. Fairmaire// Coll. L. Pandellé” [Marseille & Coll. Fairmaire HW] "Coll. A. Fauvel// (ex. coll. Pandellé)// Meladema // coriacea Lap.// R.I.Sc.N.B. 17.819 " [Latin name & describer HW] (ISNB); 1 ♂ "♂// 5188" [HW] "Coll. R. I. Sc. N. B.// France Marseille// Coll. Fairmaire// Coll. L. Pandellé” [Marseille & Coll. Fairmaire HW] "Coll. A. Fauvel// (ex. coll. Pandellé)// Meladema // coriacea Lap.// R.I.Sc.N.B. 17.819" [Latin name & describer HW] (ISNB); 1 ♂ "♂// 5188" [HW] "Coll. R. I. Sc. N. B.// France Marseille// Coll. Fairmaire// Coll. L. Pandellé” [Marseille & Coll. Fairmaire HW] "Coll. A. Fauvel// (ex. coll. Pandellé)// Meladema // coriacea Lap.// R.I.Sc.N.B. 17.819" [Latin name & describer HW] " Colymbetes Clairville// coriaceus , Hoffm.// Marseilles" [HW] (ISNB); 6 ♂♂, 2 ♀♀ "St Cyr// Ravindu// Degoutant" [HW] (MNHN); 1 ♀ "Le Beausset.// Octobre" " Meladema // coriaceum Lap." [HW] (NMW); 1 ♀ "Le Beausset.// Mol. de Boissy" (NMW); 1 ♀ "M. coriaceum " [HW] "M. de Boissy// Le Beausset Var" [HW] (NMW); 1 ♀ "Rhonetal// mont. ol. Maures// östl. Aixen Provence" [HW] "M. J. MAURES// Det. VI/81//511" [HW] (NMW); 1 ♂, 1 ♀ “Nice” [HW] "coll. P. J. Roeflofs" (ISNB); 1 ♀ "Gallia merid// Agay (Var)// 15 Juli 14// W. Liebmann// Arnstadt" [15 HW] (NMW); 2 ♂♂ "Gallia merid// Agay (Var)// 15 Juli 14// W. Liebmann// Arnstadt" [15 HW] "Collectio// Paganetti" (NMW); 1 ♂, 1 ♀ "St. Maxime// Var// G. Audran" [HW] "R. Mus. Hist. Nat.// Belg. I.G. 14.406" (ISNB); 1 ♀ “Hyères” [HW] "coll. A. Fauvel" (ISNB); 1 ♂ “Nyons” [HW] " Colymbetes // coriaceus // 22" [HW] "coll. Delgrange" (ISNB); 1 ♀ " Colymbetes // coriaceus // Capt. P. Bauret" [HW] “Trinité-Victor // Juillet 1942" [HW] (ISNB); 1 ♂ " Colymbetes // coriaceus // Lap." [HW] "Oct. 46// Le Laghet// Trinite Victor" [HW] (ISNB); 1 ♀ " Colymbetes // coriaceus // Lap." [HW] "October 1945// Le Laghet// Trinité Victor" [HW] (ISNB); 1 ♂ “Cavalaire” [HW] "f. 532 Coll.//Dr. Mouchamps" [32 HW] "Pavel Riha leg.// MELADEMA// coriacea Cast." [Latin name & describer HW] (ISNB); 3 ♀♀ "261// 131" [blue, circular label, HW] reverse “Savoy” [HW] (BMNH); 1 ♂ "[illegible]// Coll. Chevrolat// Det. Sharp 82." [HW] “3306” " Colymbetes // coriaceus // Ex Aubé 220,// Gall. mer." [HW] (ISNB); 1 ♂ "Gallia m." (NMW); 1 ♂ “8367” [blue-green label, HW] “Gallia” [HW] "Fry Coll.// 1905-100" (BMNH); 1 ♀ “Gallia” [HW] "Fry Coll.// 1905-100" (BMNH); 1 ♀ " Colymbetes // coriaceus . Hoffm.// Gehin France" [HW] (BMNH); 1 ♀ "Coriaceus// Gallia" [blue label, HW] "Sharp Coll.// 1905-31." (BMNH); 1 ♀ "Gallia 10" "Coll. Liepolt" (ISNB); 1 ♂ " coriaceus Lap.// Gallia// Bien Bacher" [HW] "c. Epplsh.// Steind. d." (NMW). Greece, mainland: 1 ♂ "Attica// Dr. Kinper" [HW] "Collect.// Hausser" (NMW); 1 ♀ "Attica// Dr. Kinper" [HW] “punctulatus” [HW] "Collect.// Hausser" (NMW). Greece, Aegina: 1 ♀ "Griechenland// Aegina// F. Werner, 13 V. 37" [Aegina & 13 HW] (NMW). Greece, Amorgos: 1 ♀ "Graecia, KYKL.// Amorgos// P. Velensky lgt.// 13.-16.5.1984" "Coll.// HENDRICH// Berlin" (ZSM); 1 ♀ "Graecia, KYKL.// Amorgos// 13.-16.5.1984// P. Velensky lgt." "Coll.// HENDRICH// Berlin" (ZSM). Greece, Chios: 1 ♀ "GR: Chios// Mai 1980// lg. Bilak, Kritscher" (NMW). Greece, Corfu: 1 ♂, 1 ♀ "GREECE: NE Corfu (GR3)// ca. 1.5 km W Zigos// 200 m a.s.l., 19.VII.08// leg. M. A. Jäch” "small shallow residual// pool in river bed// 39°43'44.4"N // 19°46'38.3"E " " Meladema // coriacea Laporte// Fery det. 2010" (NMW); 1 ♂, 2 ♀♀ "28/v/2017 Greece Corfu// nr. Zigos 233 m// 39 43 40.6N 19 46 41.0E// C R Turner leg." (CBP). Greece, Ios: 1 ♂ "Kykladen// Ios, Buch von // Milopotamos" "leg. Schönmann // 9. April 1981" [first 9 HW] (NMW); 1 ♀ "Kykladen// Ios, Buch von// Milopotamos" "leg. Schönmann // 8. April 1981" [first 8 HW] (NMW). Greece, Kithira: 1 ♀ "GR-Kithira (4)// Arlemonas 8.V.76// leg. Malicky" "Melaema// coriacea Cast.// det. Wewalka 76" [HW] (NMW). Greece, Milos: 3 ♂♂, 1 ♀ "GR-MILOS 19.9.90// 1km E. Sider ianos.// leg. M. Jäch (5)" (NMW). Greece, Naxos: 1 ♀ "GR-Naxos V.1988// leg. Bilak// et Kritscher" (NMW); 2 ♀♀ "GR-Naxos (13)// Potamia 26.V.76// leg. Malicky" (NMW). Greece, Poros: 1 ♂ "GR-Poros (2)// Kampos 17.V.74// leg. Malicky" (NMW). Greece, other: 1 ♀ "Griechenland// Kylhima// F. Werner, 26.V.37" [Kylhima & 26 HW] (NMW); 1 ♂ "Greece// Merlin Coll.// 96-275" (BMNH); 1 ♂ "Greece// Merlin Coll.// 96-275" "Spec. nov.// Hymettus" [pink label, HW] "Received with// this name// from Merlin// C. O. W." [Merlin HW] (BMNH); 1 ♂ “Graecia” " Meladema // coriaceus " [HW] "Coll. Plason" (NMW). Italy, mainland: 1 ♂ "Grotta di// Pastena// Italie merid." [HW] " Meladema // coriacea Cast." [HW] "Brit. Mus.// 1963-344." (BMNH); 1 ♂, 2 ♀♀ " Meladema // coriaceum " [HW] “Italie” [HW] "Coll. E. Dongé // Le Moult vendit" (ISNB); 1 ♂ "Coriaceus// Italia F" [HW] "R. Mouchamps det.// Meladema // coricaea Cast." [Latin name & describer HW] (NMW); 1 ♀ " Meladema // coriaceum " [HW] “Calabre” [HW] "Coll. E. Dongé // Le Moult vendit" (ISNB); 1 ♀ "Gerace, Calab.// Paganetti" "Collectio// Paganetti" (NMW); 1 ♀ "Gerace, Calab.// Paganetti" "Collectio// Paganetti" " Meladema // coriaceum " [HW](NMW). Italy, Pontine Islands: 2 ♂♂, 3 ♀♀ "Ins. Pont. - @ nos// auf Tamanis// 12-4-57// Dr. Eckerlein leg. [HW] (NMW). Italy, Sicily: 1 ♂ "Madricia// Ragusa" [HW] “3306” (ISNB); 1 ♀ "Monts Madonie 74" "E. Ragusa" (BMNH); 1 ♀ "Castelbueno// Ragusa" [HW] “3307” (ISNB); 2 ♂♂, 1 ♀ “Sicil.” "Collectio// Kaufmann" (NMW); 1 ♀ [circular label, black margin, no text] “Sicilia” [HW] "alte// Sammlung" (ZSM); 1 ♀ “Sic.” "Sammlung// C. Müller” (ZSM); 1 ♀ "Italia: Sicilia - PA// MTE. Maganoce// 900 M. Ü. N." [HW] (ZSM). Malta: 2 ♀♀ "Prof. Barthet// Malta" "29.8.25// Malta" [HW] "R.L.S.N.B.//I.G. 17.619" (ISNB); 1 ♀ “Malta” [HW] "Ex. Coll. Bettinger" (ISNB); 1 ♂ “Malta” "G.C. Champion Coll.// B. M. 1929-409" " Meladema // coriaceum Lap.// Malta" [HW] (BMNH); 1 ♂ "Buskett Gdns.// Malta// 12.XII.55.// G. V. P. Sewell" [HW] " Meladema // coriacea Cast// C. R. Smith det. 182" [Latin name, describer & 2 HW] (BMNH); 1 ♂ "MALTA// Chadwick Lakes// Mars '85// D. Johnson" [HW] (NMW). Morocco: 1 ♂, 1 ♀ "Tachdirt// Marocco// Schwingenschuss" [HW] "Coll. Liepolt" (ISNB); 7 ♂♂, 5 ♀♀ "Maroc: Azrou// 6-12-vii-1934 (1350m)// A. Ball 56 M 22" "R. Mus. Hist. Nat.// Belg. I.G. 10.417" "A. Ball det. 1935// Meladema // coriacea Cast." [1935, Latin name & describer HW] (ISNB); 1 ♀ "Middle Atlas Mts// Oviduane// 2,000ft." "MOROCCO:// K. Chapman &// J.W.S. Pringle.// B.M. 1934-554" 'MELADEMA// coriacea // Laporte" [HW] "det. J. Hajek// xi. 2008" (BMNH); 4 ♂♂, 4 ♀♀ "Middle Atlas Mts// Oviduane// 2,000ft." "MOROCCO:// K. Chapman &// J.W.S. Pringle.// B.M. 1934-554" (BMNH); 1 ♂ "Middle Atlas Mts// Oviduane// 2,000ft." "MOROCCO:// K. Chapman &// J.W.S. Pringle.// B.M. 1934-554" "Oum en Rhio Aug 20th// large beetle 400" [folded, HW, 400 in a box] (BMNH); 1 ♀ "MOROCCO// Dayet Ifrah (lake)// 16 km. E.N.E. Ifrane// 28.V.1961." [all except Morocco HW] "1334// P. N. Lawrence// B. M. 1961-328" [HW] (BMNH); 1 ♀ "MOROCCO// Great Atlas Mts.// Ijoukak. 3,900ft.// 3.vi.1936" [3 HW] "K. H. Chapman// & G. A. Bisset.// B. M. 1936-527." (BMNH); 1 ♀ "S. MORROCCO// TIZI-N-BACHKOUM env.// 25.4.1995// P. Prüdek leg." "Coll.// HENDRICH// Berlin" " Meladema // coriacea // Cast.// HENDRICH det. 1996" [name & describer HW] (ZSM); 1 ♂ "Imi n’ Ouaka// 1500m." "Maroc// 1-15 Sept." “♂” “♂” “MUSÉUM PARIS// 1960// Coll F. Guignot" (MNHN); 2 exx. "71 MOROCCO 8.4.2007// Tizi-n’Rechou, Kerrouchèn // stream on rock N pass, rd. 3437// 1570m N32°48'22.1" W5°16'13.9" // Aguilera Hernando & Ribera leg." (IBE); 1 ♀ "99 MOROCCO Chefchauen// 13.2.2015 afl. Oued Laou 150m// 35°17'57.0"N 5°12'55.5"W // Ribera, Millán & Velasco leg." (IBE); 1♂, 1♀ "Morocco// Âit-Iftene // 29, Oued Ait-Baha// 220797 Ribera, Aguilera, Hernando, Millán” (IBE); 1♂, 1♀ "Morocco// Sidi-Ibrahim// 17, 77.5 km S Guercif// 150797 Ribera, Aguilera, Hernando, Millán” (IBE); 1 ex. "MOROCCO Haut Atlas// NE Tizi-n-Test, 1710m No.18// 30°54'12 N 08°18' 39W // 30.12.2002 V.Assing & P.Wunderle" (IBE). Portugal, mainland: 1 ♂ "Portugal// Oliveira" [HW] “3306” (ISNB); 3 ♀♀ "Portugal// Oliveira" [HW] “3307” (ISNB); 1 ♀ "Portugal// Oliveira" [HW] “♀” (ISNB); 1 ♂ " Portugal// Oliveira" [HW] (ISNB); 8 ♂♂, 10 ♀♀ "PORTUGAL:// Serra do Malhao.// 8.v.1966// J. Abraham &// M. E. Bacchus.// B. M. 1966-296" "M. E. Bacchus// B. M. 1966-296" (BMNH); 1 ♀ "PORTUGAL:// Algarve. Rio Seco.// 250m ca. 10km.// W. Barranco de// Velho. 10.v.1966." (BMNH); 1 ♀ "PORTUGAL:// Algarve. Rio Seco.// 250m ca. 10km.// W. Barranco de// Velho. 10.v.1966." " Meladema // coriacea cast.// J. Balfour-Browne det.// xii. 1972" (Latin name, describer & 72 HW) (BMNH); 1 ♀ "5/v/93 Portugal// Viana do Castelo// Serra do Minho// stream @ ca. 700m// D. T. Bilton leg." [HW] (CBP); 1 ♀ "PORTUGAL: Traz os Montes// Carrazeda de Anciais// 745m., 7.viii.1966" "slow weedy// stream" "Brit. Mus.// 1973-562" " Meladema // coriacea Cast.// J. Balfour-Browne det.// IX 1969" [Latin name, describer, IX & last 9 HW] (BMNH). Spain, mainland: 1 ♂, 2 ♀♀ "Cataluna// Vall. x-42// Español” [HW] "R. Mouchamps det 1948// MELADEMA// coriacea Cast." [8, Latin name & describer HW] (ISNB); 2 ♂♂ "Vallvidrera// Barcelona// VIII.1948// Español” [HW] "R. Mouchamps det.// Meladema // coriacea Cast." [Latin name & describer HW] (ISNB); 2 exx. "Barcelona// Montseny d’Amunt // Riachuelo: remanso// 290988 I. Ribera" (IBE); 1 ♂ "Girona// Capmany// Estanys: alberca// 041189 I.Ribera" (IBE); 3 ♂♂, 1 ♀ "Girona// Capmany// Estanys: alberca// 110389 I.Ribera" (IBE); 4 ♂♂, 3 ♀♀ "Girona// Capmany// Estanys: alberca// 281090 I. Ribera" (IBE); 6 ♂♂, 3 ♀♀ "Girona// Capmany// Estanys: alberca// 251190 I. Ribera" (IBE); 4 ♂♂, 3 ♀♀ "Girona// Capmany// Estanys: alberca// 120191 I.Ribera" (IBE); 2 ♀ "Girona// Capmany// Estanys: alberca// 171294 I. Ribera & P. Aguilera" (IBE);1 ♂ "Girona// Capmany// Estanys: alberca// 100994 I.Ribera & P.Aguilera" (IBE); 2 exx. "1 GIR La Junquera 4.x.2014// estanys de Capmany: alberca// 42°24'20.5"N 2°54'8.0"E // 188m I. & B.Ribera leg." (IBE); 1 ♂ "Girona// Capmany// Querafumat: abrevadero 1// 251190 I. Ribera" (IBE); 2 ♂♂, 1 ♀ "2 ES Girona, Port Bou// Cami de la Riera, 10.5.2012// N42°25'38.2" E3°08'13.4" // 81m I.Ribera & A.Cieslak leg." (IBE); 2 ♂♂, 2 ♀♀ "Girona// Sta. Pau// Rio Ser: remanso 1b// 260890 I. Ribera" (IBE); 1 ♀ "Girona// Sta. Pau// Rio Ser: remanso 2// 260890 I. Ribera" (IBE); 2 ♂♂, 1 ♀ "1 ES Girona, Port Bou// Cami de la Riera, 28.6.2013// 42°25'34.5"N 3°8'9.3"E // 65m I.Ribera & A.Cieslak leg." (IBE); 1 ex. "Tarragona// Vila-rodona// Jardín: alberca// 110985 M. Galán” (IBE); 1 ex. "Tarragona// Vila-rodona// Jardín: alberca// 201085 I.Ribera" (IBE); 2 ♂♂, 2 ♀♀ "16/v/1994// SPAIN Tarragona// stream 2km SW of// Esblada D. T. Bilton leg." (CBP); 1 ♂, 3 ♀♀ "3 ES Huesca 6km S Bernués // Bco. de Bernués 6.9.2013// 42°26'38"N 0°36'51"W // 690m I.Ribera & A.Cieslak leg" (IBE); 3 exx. "1 ES Castellón, Ballestar// r. Sénia, pools upstr. reservoir// 500m N40°41'41" E0°13'25.5" // I. Ribera leg. 2.6.2006" (IBE); 1 ♂, "Teruel// Calaceite// Riu Matarranya// 240794 I.Ribera & P.Aguilera" (IBE); 1 ♂, 1 ♀ "19/ix/1999 SPAIN Murcia// Fte. Caputa, Rio Mula// A. Millán leg." (IBE); 1 ♂ "19/ix/1999 SPAIN Murcia// Fte. Caputa, Rio Mula// A. Millán leg." "Fte Caputa// R. Mula 19-9-99// A. Mellado" [HW] (IBE); 1 ♂ "19: SPAIN: CACERES:// 21 km S of Aldeanuo// del Camino: granite// stream 18 April 1985" (CBP); 1 ♂, 1 ♀ "12/v/1990 SPAIN Cáceres // stream with pools 7km N of// Plasencia on N630 road" (CBP); 2 ♀♀ "27/iv/1993// Spain Extremadura// Cáceres stream by N630// 15km N of Plasencia" (CBP); 1 ex. "3 ES Cáceres, PN Monfragüe // Arroyo de Malvecino// N39°51'04.0" W6°02'22.3" 284m// I.Ribera & P. Abellán leg. 12.6.2008" (IBE); 1 ♀ "SPAIN: Cordoba.// Posadas - Villaviciosa Rd.// 20 Km N. of Posadas// Arroyo Calderas. 500m.// 14.V.1967" " Meladema coriacea // CAST. I. RIBERA det 1990" [HW] (BMNH); 1 ♂ "MALAGA// H. Clark.// May 1856" "Fry Coll.// 1905-100" (BMNH); 2 ♀♀ "MALAGA// H. Clark.// May 1856" (BMNH); 1 ex. "1 ESP. Malaga 3.1.03// Villanueva del Trabuco// r. Guadalhorce, cta. MA156// I.Ribera & A.Cieslak leg." (IBE); 1 ♂, 1 ♀ “Almería // Tabernas// Rbla. de Tabernas: charca 1// 110597 I.Ribera & A. Millán” (IBE); 1 ♂ “Nerja” [HW] (MNHN); 1 ♂ "24/iv/1993// Spain Andalucia Cadiz// Drying stream by N340// 28km N of Tarifa" (CBP); 1 ♀ "17: SPAIN: HUELVA: 1 km// S. of Santa Ollala del// Cala: weedy stream:// 18 April 1985// R.B. Angus & G.N. Foster" " Meladema corac" [HW] (BMNH); 2 ♂♂, 1 ♀ "17: SPAIN: HUELVA: 1 km// S. of Santa Ollala del// Cala: weedy stream:// 18 April 1985// R.B. Angus & G.N. Foster" "R. B. Angus// BMNH(E) 2010-22" (BMNH); 1 ♂, 1 ♀ “Hispania” [HW] " Meladema // Lap.// coriacea // Cast." [HW, genus name on green label, glued on top of original] "Coll. Martin// Le Moult vendit" (ISNB); 1 ♂, 1 ♀ “Hispan” [HW] "Fry Coll.// 1905-100" (BMNH); 1 ♂ "Hispa// nia" [HW] "57.// 107." [blue, circular label, HW] (BMNH). Spain, Mallorca: 2 exx. "1 Mallorca, Lloseta 13.5.2007// te. des Estorall, potabilizadora// 170m N39°43'49.7" E2°50'04.6" // I.Ribera & A.Cieslak leg." (IBE); 1 ♂, 1 ♀ "2 Mallorca, Bunyola 13.5.2007// te. de Bunyola, Ma 2100 pk 5.5// 455m N39°43'24.7" E2°43'15.7" // I.Ribera & A.Cieslak leg." (IBE); 1 ♂ "Inca, Majorca.// March.// O. Thomas &// R. I. Pocock.// 1900-215" (BMNH). Spain, Canary Islands: 2 ♀♀ "Canary Is.// Gran Canaria,// Sta Brigida.// 5.ix.1927.// E. Appenhagen.// B. M. 1928-20" [5 & ix HW] (BMNH); 1 ♂ "Canary Is.// Gran Canaria,// Sta Brigida.// 5.ix.1927.// E. Appenhagen.// B. M. 1928-20" [5 & ix HW] " Colymbetes // coriaceus , Cast.// 5-9-27.// 206" [HW] (BMNH); 1 ♀ "CANARY IS.// Gran Canaria// 29.xii.92-11.i.93" "Bco de// Ayagaures// ca 100 m." [HW] "P. M. Hammond// B. M. 1993-11" " coriaceus " [HW] (BMNH); 1 ♂ "Barranco de// Temise près Haria// (Lanzarote) 2" [HW] "coll. A. Fauvel" (ISNB); 1 ♀ " Colymbetes // coriaceus Hoffm.// Bajamar XI. 1909" [HW] "Le Moult vend." (ISNB); 1 ♂ "Teneriffa// geibelez" [HW] "DON// P DUPUIS" (ISNB); 1 ♀ " Colymbetes Clairv.// 203 coriaceus Lap.// 6 ex Teneriffe 1904 (Prevost):Elliott Coll." [HW, folded] "Claude Morley// Collection// B.M. 1952-159" " Meladema // coriacea Cast.// C. R. Smith det. 1982" [Latin name, describer & 2 HW] (BMNH); 2 ♂♂, 1 ♀ "Claude Morley// Collection// B.M. 1952-159" [part of same series as previous] (BMNH); 1 ♂ "Claude Morley// Collection// B.M. 1952-159" " Meladema // coriacea Cast.// C. R. Smith det. 1982" [Latin name, describer & 2 HW] [part of same series as previous] (BMNH); 2 ♂♂, 2 ♀♀ "Canary Is.// Teneriffe,// Guajonje,// 17.iii.1927// E. Appenhagen" [Guajonje & date HW] (BMNH); 1 ♀ "Canary Is.// Teneriffe,// Guajonje,// 17.iii.1927// E. Appenhagen" [Guajonje & date HW] " Colymbetes // coriaceus , Lap.// G. J. Arrow det." [Latin name & describer HW] (BMNH); 1 ♂ "Tenerife// Barr. Bufadno" [HW] "6.2.1949// Fernandez" [6, 2 & last 9 HW] "Brit. Mus.// 1951-318" " Meladema // coriaceum Lap.// Harald Lindb. det" [Latin name & describer HW] (BMNH); 1 ♂ "ES: Tenerife// Masca 12 April// 1991 AN Nilsson" " Meladema coriacea // Laporte, 1835// Det AN Nilsson 1991" (CBP); 1 ♂ "April 1998 SPAIN// Islas Canarias Tenerife// Bco. del Infierno Pools// D.T. Bilton leg." (CBP); 1 ♂, 1 ♀ "April 1998 SPAIN// Islas Canarias Tenerife// Bco. de Masca Pools// D.T. Bilton leg." (CBP); 1 ♀ "29/xi/97 Tenerife// Anaga Massif - stream// @ Iguana D.T. Bilton" [HW] (CBP); 1 ♀ “CANARIES” "Coll. R. Van Dorsselaer" (ISNB); 1 ♀ "Canary Is.// 1903 (Prevost)// coll. Elliott. 36" [HW] "Claude Morley// Collection// B.M. 1952-159" (BMNH). Tunisia: 3 ♀♀ "TUN.: 3.8.91(7)// Beni Melir SE// A. Draham, Schödl” (NMW). Turkey: 1 ♀ "Asia min. occ.// Izmir (H. Mudja)// 20 m. St. 71// 8-V-'31 (Orch.)" "Reg. Mus. Hist. Nat.// Belg. I.G. 9642" "A. Ball det. 1935// Meladema // coriacea Cast." [1935, Latin name & describer HW] (ISNB). Without locality data: 1 ♂ "Coll Abcedal" [HW] " Colymbetes // coriaceus " [HW] "R.I.Sc.N.B. 21.418// Coll. P. de Moffarts" " Meladema // coriaceum // Lap." [green label, HW] (ISNB); 1 ♂ "Coll Abcedal" [HW] "Coll. P. de Moffarts" (ISNB); 1 ♀ " Meladema // coriaceum // Coll. Hevon" [HW] "Ex coll. Bettinger" (ISNB); 1 ♂ “121” " Meladema // coriaceum " [HW] "Ex. Coll. Bettinger" (ISNB); 1 ♂ "ex coll R P David// ex coll Peres Jesuites// (Le Moult vendit)" " coriaceus Cast.// Region mediterranee" [HW] (ISNB); 1 ♂ "Coll. P. Boppe// Le Moult vendit" " Meladema // coriaceum // Cast." [HW] (ISNB); 1 ♂ " Meladema // coriaceum " [HW] "Coll. E. Dongé // Le Moult vendit" (ISNB); 1 ♂ "H Guyon" [HW] "Coll. E. Traizet// Le Moult vendit" (ISNB); 7 ♂♂, 4 ♀♀ "coll. A. Fauvel" (ISNB); 1 ♂ "coll. Delgrange" (ISNB); 1 ♂ "G. C. Champion Coll.// B. M. 1927-409" (BMNH); 1 ♀ "Coll. Odier.// B. M. 1921-288" (BMNH); 2 ♀♀ [small, circular brown label, no text] "Coll. Odier.// B. M. 1921-288" (BMNH); 1 ♂ "Alono-// dorsar" [? HW] " Meladema // coriacea " [HW] (BMNH); 1 ♂ "Europa// B. Heyne" [HW] (BMNH); 1 ♂ " coriaceus Lap." [folded, HW] (BMNH); 1 ♂ " Dytiscus coriaceus // no. in list. 19." [HW] reverse "Presented by// Signor Passerini" [name HW] (BMNH); 1 ♂ “1911” [round label, HW] (BMNH). All with " Meladema // coriacea Laporte, 1835// D T Bilton [or I Ribera] det. 2017".

Description.

Size: Neotype TL = 22.66 mm; EL = 16.90 mm; MW = 11.52 mm. Other material examined TL = 18.56-23.17 mm; EL = 14.34-16.90 mm; MW = 8.45-11.14 mm.

Colour. Dorsum dark reddish brown to black (Figure 3A); lateral margins of pronotum, labrum and anterior half of clypeus somewhat paler, sometimes with diffuse lateral maculae. Elytra unicolorous, without distinct mottling even when lifted (Figure 4A). Head with a pair of oval, reddish yellow medial interocular patches, slightly elongated apicolaterally. Antennae and maxillary and labial palpi reddish yellow. Legs dark reddish brown to black with golden yellow setae; large spines somewhat paler. Venter reddish brown to black; gula, meso and metacoxae and trochanters paler.

Head. Labrum shining, with moderate to coarse, sparse punctures. Reticulation absent in apical half, becoming increasingly more evident basally, here forming weakly impressed, transverse meshes. Clypeus and anterior half of frons shining, doubly punctate, without reticulation and with very close, fine and very sparse, coarse punctures. Coarse punctures approximately 5-8x diameter of fine; without visible reticulation. Paired epicranial foveae, one immediately behind the other, on each side of frons, close to lateral margins and immediately behind lateral remnants of frontoclypeal suture. Anterior epicranial foveae transverse, posterior slightly elongate oval; both with cluster of stout, yellow recumbent to decumbent setae. Areas between anterior and posterior foveae with coarse wrinkles. Posterior frons with open, elongate, wrinkled reticulation, especially alongside lateral margins of compound eyes and onto vertex; meshes tumid, with rugose appearance. Internal and posterior borders of compound eyes distinct, raised relative to level of adjacent cuticle. Lateral margins bordered by distinct narrow channel; deeper anteriorly than posteriorly and continuing behind posterior margin of eye onto vertex. Channel with dense punctures, bearing long, stiff, yellow recumbent to decumbent setae.

Pronotum. Posterior margin strongly sinuate laterally (Figure 3A). Surface somewhat shining, strongly rugose. Reticulation meshes large, open, almost isodiametric and relatively flat either side of mid-line on disc; smaller, tumid and more uneven in size and shape towards all margins. Transverse irregular row of medium punctures bearing long, yellow recumbent to decumbent setae 1/5 behind anterior pronotal margin; interrupted briefly in centre, continuing inside lateral margins and inside lateral third of posterior margin. Centre of disc with elongate, narrow, slit-like fovea, sometimes partially interrupted in mid-length. Lateral margins slightly raised, shining, without rugose sculpture and with fine, scattered punctures.

Elytra. Somewhat shining, with dense, transverse, crescentic striolae (Figures 5A, 6A) giving a scaly appearance (Figure 3A). Striolae less dense anteriorly and medially, here mostly distinctly separated from each other laterally (e.g. Figures 5A, 7A, C, 8A, C, 9, 10). Size of crescentic striolae variable, especially on disc close to suture (e.g. Figures 9, 10). Crescentic striolae becoming denser and somewhat continuous laterally and posteriorly (Figure 3A). Surface between crescentic striolae (Figures 5A, 6A) doubly punctate, with very fine, close punctures and medium, very sparse punctures (the latter bearing short, peg-like setae); also with fine, obsolete, open reticulation, usually more evident in apical two thirds, and more evident in some specimens than others; sometimes apparently absent. Puncture rows well-marked, continuous almost to elytral apices; punctures shallower posteriorly than anteriorly.

Venter. Prementum shining, tumid in centre, with fine and medium, sparse punctures. Mentum shining; central projection with shallow median emargination. Lateral lobes with medium, sparse punctures, and scattered, whitish recumbent to decumbent setae. Submentum shining, with transverse wrinkles centrally, and elongate wrinkles laterally. Central 1/4 with medium, sparse punctures bearing long, white-yellowish, erect setae. Gula shining, with sparse, shallow, transverse wrinkles; patch of medium-coarse punctures posterolaterally. Genae shining, with obsolete, open, elongate reticulation. Prosternum shining, with irregular transverse ridges laterally. Strongly arched in centre and with fine, moderate to close punctures laterally, bearing long, white-yellowish, recumbent to erect setae; punctures and setae extending in a sparse, irregular row onto process, just below arch. Process lanceolate, tectiform; apex acuminately rounded. Centre of prosternum and process with double punctation of very fine, moderate and medium, very sparse punctures. Pronotal hypomeron shining, impunctate. Elytral epipleurs shining, with fine wrinkles; irregular puncture row close to internal margin, from centre to close to apex; punctures bearing fine, whitish, erect setae. Metaventrite shining, central portion with sparse, transverse scratches and fine to very fine, sparse to very sparse punctures; not clearly forming two size classes. Metaventral process strongly reticulate, with transverse, rugose meshes and traces of fine, sparse punctures; small, central patch at base with very small reticulation meshes. Metaventral process relatively broad; apex acuminate and upturned slightly anterolaterally. Metacoxal lines almost reaching anterior border of metacoxae; shallow and interrupted in anterior 1/5. Internal laminae of metacoxae shining, sculpture as on centre of metaventrite. Metacoxal lobes sculptured as internal laminae, strongly rounded, with irregular, elongate field of medium to coarse punctures close to lateral margins, bearing fine, white, recumbent to erect setae. External laminae of metacoxae shining, smooth close to process, but with strong reticulation elsewhere; reticulation meshes very elongate posteromedially, to transverse anteriorly. Abdominal ventrites shining. Ventrites 3-5 with cluster of golden, erect setae anteromedially. Ventrite 1 with elongate reticulation throughout. Ventrite 2 with similar reticulation; absent close to centre. Ventrite 3 with elongate reticulation laterally, becoming transverse close to smooth central 1/5. Reticulation of ventrites 4 and 5 restricted to lateral third and with superimposed elongate furrows. Ventrites 2-5 doubly punctate; very fine, moderate and fine, sparse to very sparse punctures; punctures most evident in areas without reticulation. Ventrites 3-5 with transverse irregular row of long, yellowish, recumbent to decumbent setae laterally. Ventrite 6 (Figure 11A) with very fine, moderate punctures and medium to coarse, sparse to moderate punctures; punctures coarser close to apex. Elongate, semicircular wrinkles and channels apicolaterally. Some punctures in channels bearing elongate, whitish, erect setae.

Male. Foretarsi (Figure 12A) with articulo-setal counts as follows (base to apex): row 1, 7; row 2, 8-10; row 3, 8-10; row 4, 6-8. Number of setae in rows may differ from right to left tarsus in same beetle. Curved, golden setae bordering articulo-setal field dense, particularly basally. Foretarsal claws (Figures 12A, 13A) elongate, curved; interior margin straight or somewhat raised in basal two thirds, strongly curved in apical third. Mesotarsi (Figure 12E) with articulo-setal counts as follows (base to apex): row 1, 7-8; row 2, 8; row 3, 7; row 4, 4 (2 clusters of 2, situated laterally). Curved, golden setae bordering articulo-setal field dense, particularly basally. Mesotarsal claws (Figure 12E) elongate, strongly curved. Abdominal ventrite 6 (Figure 11A) with apex rounded, with very shallow median emargination. Median lobe asymmetrical (Figure 14A), sinuation weak, approximately 1/5-1/4 from apex; ventral margin of apical portion relatively straight in lateral view. Parameres (Figure 14A) with basal portion of inner margin relatively evenly curved; outer and inner margins almost straight over apical two thirds.

Female. As male, except for simple fore and mesotarsi, differently shaped abdominal ventrite 6 (with bluntly pointed apex, Figure 15A). The density of crescentic strio lae on the elytra does not differ consistently between sexes, contrary to the statement of Balfour-Browne (1948).

Variation. Variation is evident in a number of characters. The size and density of the crescentic striolae on the elytra differs between individuals (e.g. Figures 5A, 7A, C, 8A, C, 9, 10, 17, 18D, 19), and shows some geographical structure. Specimens of both sexes from the Iberian Peninsula (e.g. Figures 7A, C, 8A, C, 9B, 10B) have relatively sparse crescentic striolae, with individual striolae relatively small in size, features also seen in most specimens from the Balkans and Anatolia (e.g. Figure 10A). Some specimens from France, North Africa and southern Italy (e.g. Figures 9D, 10C, D, 19) have slightly denser striolae, with some of these slightly larger. Specimens from massifs in the central Sahara (Hoggar and Tassili n’Ajjer (Algeria), Tibesti (Chad)) have very dense crescentic striolae (Figure 17). In these beetles the striolae are relatively small and strongly curved, giving a distinctly tuberculate appearance to the elytra, even close to the shoulders. In no cases do the elytral striolae approach the condition seen in M. lepidoptera sp. n., however (see below). The degree of curvature of male foretarsal claws differs between individuals, even within the same population. Some specimens have claws which are shorter, and broader at their apices that in Figure 13A, these almost certainly being older insects, whose claws have become worn down during life. The size and shape of the median lobe also varies slightly between individuals and populations (e.g. Figure 20). Specimens from North Africa, for example, (Figure 20 H–K) have narrower apical portions, whilst the largest median lobes are seen in Greek animals (Figure 20 M–N).

Differential diagnosis.

Morphologically, this species is almost identical to M. lepidoptera sp. n., something which has prevented the latter’s formal description until now. The two species can be reliably separated only on details of their elytral sculpture, M. coriacea having smaller, less dense crescentic striolae than M. lepidoptera sp. n., this being particularly evident at the elytral base, close to the scutellum, and in the middle, close to the suture (see Figure 1 and e.g. Figures 7A, C, 8A, C, 9, 10 vs. 7B, D, 8B, D, 21, 22). In M. coriacea , the striolae are largely well separated from each other in both regions (see comment by Aubé 1836, quoted above) whereas in M. lepidoptera sp. n. they are typically much more contiguous (see below). In the mid-elytra of M. coriacea there is also typically a distinct gap between the elytral suture and the first crescentic striolae (see e.g. Figure 8A, C), whereas in M. lepidoptera sp. n. the striolae begin much closer to the suture (e.g. Figure 8B, D). Whilst there is some variation, as illustrated in the figures, these features appear consistent throughout the wide geographical range of M. coriacea . Other characters, including male genitalia, claws, and the shape and sculpture of abdominal ventrite 6 in both sexes, do not differ consistently between the two species, there being as much intraspecific as interspecific variation.

The genetic differences between M. coriacea and M. lepidoptera sp. n. are well defined and comparable to those seen between M. imbricata and M. lanio , although mostly seen in mitochondrial markers ( Sýkora et al. 2017). Of the two nuclear markers sequenced, H3 was identical in M. coriacea and M. lepidoptera sp. n. (but differ ent from M. lanio and M. imbricata ), only wingless having some diagnostic positions separating the two species (see Sýkora et al. 2017).

Distribution.

Even as redefined here, this is by far the most widespread species of the genus, distributed from the Canary Islands to Turkey, and south to massifs of the central Sahara (Figure 23). We have examined material from all countries from which this species has been reported, with the exception of Bulgaria ( Guéorguiev 1987). Despite being listed from Lybia in the Palaearctic and World Catalogues of Dytiscidae ( Nilsson and Hájek 2017a, 2017b), all Saharan records which we have traced emanate from Algeria and Chad. As discussed by Sýkora et al. (2017), basal splits within the M. coriacea lineage apparently took place in north-west Africa, with subsequent range expansion across the western Mediterranean, and several apparently independent, recent, colonisations of the Canary Islands from Morocco. The most easterly specimens included in genetic analyses (from Malta and Izmir, Turkey) were more closely related to beetles from north Africa than those from Iberia or southern France, suggesting that colonisation of the eastern part of the species range occurred via dispersal from Algeria/Tunsia, likely through Malta, Sicily and southern Italy. Genotyped individuals have been studied from throughout the wide range of M. coriacea , as well as a large number of additional non-genotyped specimens (Figure 23). The exact limits of M. coriacea in the Italian Peninsula remain unclear, and can only be resolved through combined genetic and morphological study of additional, fresh material. It is apparent, however, that M. coriacea is present in at least Sicily and that M. lepidoptera sp. n. occurs in the north and centre of the peninsula (Toscana and Lazio - as confirmed from genotyped specimens). Beetles morphologically intermediate between M. coriacea and M. lepidoptera sp. n. have been seen from Apulia and Campania (Figure 18B, C), suggesting possible hybridization between the two species where their ranges come into contact. Such a process is already established to have occurred between M. coriacea and M. imbricata on Tenerife (see below and Ribera et al. 2003). Meladema coriacea is a species typical of seasonally fluctuating or intermittent Mediterranean stream systems, being particularly characteristic of localities with winter-spring flow, which dry down to pools in summer. It is associated with drier and more seasonally variable conditions than other species of the genus, something which may have facilitated its range expansion ( Sýkora et al. 2017).