Hypocaccus (Baeckmanniolus) dimidiatus ( Illiger, 1807 ), 1926

Lackner, Tomáš, 2010, Review of the Palaearctic genera of Saprininae (Coleoptera: Histeridae), Acta Entomologica Musei Nationalis Pragae (suppl.) 50, pp. 1-254 : 146-150

Hypocaccus (Baeckmanniolus) dimidiatus ( Illiger, 1807)

( Figs. 21 , 45 , 91 , 121 , 453–470 )

Hister dimidiatus Illiger, 1807: 41 . Hister dimidiatus: PAYKULL (1811) : 73, t. VI, Fig. 8 . Hister semiaeneus Brullé, 1832: 159 . Synonymized by GEMMINGER & HAROLD (1868): 785. Saprinus dimidiatus: ERICHSON (1834) : 195; MARSEUL (1855): 730, t. XX, Fig. 162 ; SCHMIDT (1885a): 317; GANGL-

BAUER (1899): 393; JAKOBSON (1911): 651. Hister tauricus: DEJEAN (1837) : 142 (nomen nudum, given as synonym). Saprinus semiaeneus: KRAATZ (1858) : 131. Saprinus lobatus Wollaston, 1864: 178 . Synonymized by MARSEUL (1870): 134. Pachylopus dimidiatus: Zimmermann in J. L. LECONTE (1869): 253. Pachylopus lobatus: LEWIS (1905) : 76. Saprinus dimidiatus var. hummleri J. Müller, 1899: 154 . Saprinus dimidiatus hummleri: JAKOBSON (1911) : 651. Hypocaccus (Baeckmanniolus) dimidiatus: REICHARDT (1926) : 14; G. MÜLLER (1931): 101; PEYERIMHOFF (1936): 229;

REICHARDT (1941):323, Figs. 168, 169 ; HORION (1949): 344; DAHLGREN (1969):66, 70, Figs. 3E, F; KRYZHANOVSKIJ

& REICHARDT (1976): 220, 231, Figs. 451 , 454 ; VIENNA (1980): 194, Fig. 68 ; MAZUR (1981a): 104, Fig.139 ; MAZUR

(1984): 99; MAZUR (1997): 262; YÉLAMOS (2002): 336, Figs. 161F , 163F, 166H , 168 ; MAZUR (2004): 94. Baeckmanniolus convexicollis G. Müller, 1937: 118 . Synonymized by MAZUR (1997): 262. Hypocaccus (Baeckmanniolus) dimidiatus var. camarguensis Thérond, 1948: 126 . Hypocaccus convexicollis: MAZUR (1984) : 98. Note. Sensory structures of the antennal club and spermatheca were studied by DE MARZO & VIENNA (1982a,b).

Type locality. Portugal.

Material examined. MOROCCO: Bouknadel , vi.1976, 1 ♁ 2 spec., Z. Táborský lgt .; ditto, but 27.ix.1975, 1 ♁ ( TLAN) .

Redescription. Body length: PEL: 2.75–3.65 mm; APW: 1.125 –1.375 mm; PPW: 1.875–2.75 mm; EL: 1.625–2.25 mm; EW: 2.00–3.00 mm.

Body ( Figs. 453–454 ) rectangular oval, convex, cuticle dark brown to black; pronotum sometimes with feeble bronze hue; legs, mouthparts and antennae castaneous to dark brown.

Antennal scape ( Fig. 456 ) somewhat thickened, with numerous well sclerotized moderately long setae; club ( Fig. 455 ) round, without visible articulation, its entire surface with thick short yellow sensilla intermingled with sparse longer sensilla; sensory structures of antennal club ( Fig. 21 ) in form of stipe-shaped vesicle situated under circular sensory area on internal distal margin of the ventral side of antennal club, supplemented by another sensory area situated opposite to it.

Mouthparts. Mandibles ( Fig. 91 ) with rounded outer margin, strongly curved inwardly, acutely pointed; sub-apical tooth on inner margin of left mandible large, almost perpendicular; labrum ( Fig. 45 ) with scattered microscopic punctation, somewhat convex, with a slight median depression and a tiny median convexity interrupting concavity; two well impressed labral pits present, with two well-sclerotized setae arising from each pit; terminal labial palpomere elongate, its width about one-third its length; mentum square-shaped, anterior margin ( Fig. 121 ) medially with shallow emargination, surface around it with several moderately long setae; posterior angles somewhat produced; lateral margins with a single row of much shorter setae; disc of mentum with sparse short setae; cardo of maxilla with two short setae on lateral margin; stipes triangular, with three much longer setae; terminal maxillary palpomere elongated, its width about one-fourth its length, approximately twice as long as penultimate.

Clypeus ( Fig. 456 ) rectangular, slightly rounded laterally, with irregular shallow impressions; frontal stria ( Fig. 456 ) well impressed, almost straight (sometimes somewhat curved outwardly), carinate, continued as carinate supraorbital stria. Frontal disc smooth, with single deeply marked chevron, rarely with minute fragments of rugae; eyes somewhat flattened, conspicuous from above.

Pronotal sides ( Fig. 453 ) almost parallel, apical angles somewhat produced; marginal pronotal stria complete; disc (except for a double row of round punctures along base) smooth; scutellum small, visible.

Elytral epipleura with microscopic punctures, almost smooth; marginal epipleural stria complete; marginal elytral stria deeply impressed, continued as well impressed complete apical elytral stria; along elytral marginal stria regular row of round punctures present. Humeral elytral stria well impressed on basal fourth; inner subhumeral stria present medially, rather short. Elytral disc with four variably long dorsal elytral striae 1–4, usually reaching elytral half, occasionally shortened, fourth dorsal elytral stria basally connected with sutural elytral stria. Sutural elytral stria well impressed and complete, apically connected with complete apical elytral stria. Punctation of elytral disc round, coarse and dense, punctures separated by about half to their own diameter; punctation variable, usually reaches about two-thirds of elytral length anteriorly, punctures along elytral apex aciculate; lateral elytral margins, elytral humeri and usually first and second interval between dorsal striae as well as interspace between sutural and fourth dorsal elytral striae impunctate.

Punctation of propygidium and pygidium less dense and coarse than that of elytra, punctures separated by about their own diameter.

Anterior margin of median portion of prosternum ( Fig. 458 ) obtuse-angulate, pre-apical foveae small, deep. Prosternal process slightly concave; surface between carinal prosternal striae smooth, laterally substrigulate, intermingled with sparse large punctures; carinal prosternal striae slightly carinate, divergent on prosternal apophysis, almost parallel, united in front (at times not united); lateral prosternal striae well impressed, strongly carinate, convergent anteriorly, united in front of apices of carinal prosternal striae.

Anterior margin of mesoventrite slightly emarginate medially; discal marginal mesoventral stria deeply impressed, carinate; meso-metaventral sutural stria vaguely impressed in shallow punctures; disc of mesoventrite flat, smooth; intercoxal disc of metaventrite smooth, basally with irregular sparse shallow fine punctures with a longitudinal median excavation in male; lateral metaventral stria ( Fig. 459 ) well impressed, carinate, curved outwardly, stopping short of metacoxa; lateral disc of metaventrite ( Fig. 459 ) slightly concave, with shallow dense setiferous punctures of various sizes; metepisternum + fused metepimeron ( Fig. 459 ) with even coarser and denser setiferous punctures.

Intercoxal disc of the first abdominal sternite completely striate laterally, almost smooth, only with sparse punctures along basal and lateral margins; basally with a shallow concavity.

Protibia ( Figs. 460–461 ) flattened and somewhat dilated, outer margin with four moderately large triangular teeth topped with short rounded denticle followed by three minuscule denticles; setae of outer row moderately dense, regular and short; setae of median row similarly dense and regular, somewhat shorter than those of outer row; protarsal groove moderately deep; anterior protibial stria shortened, present only as basal fragment; two tiny tarsal denticles present apically; protibial spur tiny, straight, growing out from apical protibial margin; apical margin of protibia posteriorly with two tiny rounded, widely separated apical denticles; outer part of posterior surface of protibia ( Fig. 460 ) areolate-rugose, with four irregularly situated minuscule denticles; distinctly separated from glabrous median part of posterior surface; posterior protibial stria complete, somewhat carinate, terminating in three tiny inner-ventral denticles; inner margin with single row of short setae.

Mesotibia slender, outer margin with three dense rows of moderately thick denticles abutting each other, growing in size apically; setae of outer row rather sparse, but strongly sclerotized and as long as denticles themselves; setae of median row regular, much thinner and shorter than those of outer row; posterior mesotibial stria shortened apically; anterior surface of mesotibia glabrous; anterior mesotibial stria shortened apically; mesotibial spur stout, rather long; apical margin with several rather stout and moderately long denticles; claws of apical tarsomere shorter than half its length; metatibia basically similar to mesotibia, but slenderer and rows of denticles much sparser than those of mesotibia.

Male genitalia. Eighth sternite ( Figs. 462–463 ) longitudinally entirely fused medially, apically with large inflatable membrane (velum) covered with moderately long dense setae; eighth tergite and eighth sternite not fused laterally ( Fig. 464 ). Morphology of 9 th tergite ( Figs. 465–466 ) typical for the subfamily; spiculum gastrale ( Fig. 469 ) expanded on both ends. Basal piece of aedeagus ( Figs. 467–468 ) rather short, ratio of its length: length of parameres 1: 4; parameres fused approximately along their basal half; aedeagus curved ventrad ( Fig. 468 ).

Remarks. This species consists of two subspecies: Hypocacculus (Baeckmanniolus) dimidiatus dimidiatus and Hypocacculus (Baeckmanniolus) dimidiatus maritimus . They differ in elytral punctation, length of the dorsal elytral striae, size, color of the cuticle and variously thickened metacoxa and metafemora. Their geographical distribution is also separate: the nominotypical subspecies lives on the shores of Mediterranean and Black Seas and on the Atlantic coast of North Africa (including the Canary Islands and Azores) and the subspecies maritimus is spread along the coasts of the north-western Europe (including England and Ireland) as far north-east as Bornholm Island ( Denmark) ( MAZUR 1997).

Figures

Figs. 9–28. Saprininae, sensory structures of the antennal club (vesicles marked with grey; sensory areas shaded): 9 – Saprinus (Saprinus) semistriatus (Scriba, 1790); 10 – Saprinus (Hemisaprinus) subvirescens (Ménétries, 1832); 11 – Myrmetes paykulli Kanaar, 1979; 12 – Styphrus corpulentus Motschulsky, 1845; 13 – Saprinus (Phaonius) pharao (Marseul, 1855); 14 – Ammostyphrus cerberus Reichardt, 1924; 15 – Chalcionellus amoenus (Erichson, 1834); 16 – Chivaenius kryzhanovskii Olexa,1980; 17 – Ctenophilothis chobauti (Théry,1900); 18 – Eopachylopus ripae (Lewis, 1885); 19 – Exaesiopus grossipes grossipes (Marseul, 1855); 20 – Hypocaccus (Hypocaccus) rugiceps (Duftschmid, 1805); 21 – Hypocaccus (Baeckmanniolus) dimidiatus dimidiatus (Illiger, 1807); 22 – Hypocacculus (Hypocacculus) metallescens (Erichson, 1834); 23 – Hypocacculus (Colpellus) praecox (Erichson, 1834); 24 – Hypocacculus (Nessus) rubripes (Erichson, 1834); 25 – Paravolvulus lateristrius (Solskij, 1876); 26 – Pholioxenus phoenix (Reichardt, 1930); 27 – Reichardtiolus duriculus (Reitter, 1904); 28 – Xenonychus tridens (Jacquelin-Duval, 1852).

Figs. 45–46. Dorsal structure of labrum showing presence/absence of labral pit and seta (left half showing external and right half showing internal structures): 45 – Hypocaccus (Baeckmanniolus) dimidiatus (Illiger, 1807); 46 – Ctenophilothis chobauti (Théry, 1900).

Figs. 90–98. Saprininae, mandibles, ventral view: 90 – Gnathoncus rotundatus (Kugelann, 1792); 91 – Hypocaccus (Baeckmanniolus) dimidiatus dimidiatus (Illiger, 1807); 92 – Hypocacculus (Hypocacculus) metalescens (Erichson, 1834); 93 – Hypocacculus (Colpellus) praecox (Erichson, 1834); 94 – Hypocacculus (Nessus) rubripes (Erichson, 1834); 95 – Myrmetes paykulli Kanaar, 1979; 96 – Paravolvulus lateristrius (Solskij, 1876); 97 – Philothis (Philothis) arcanus Reichardt, 1930; 98 – Philothis (Atavinus) atavus (Reichardt, 1931).

Figs. 109–141. Saprininae, anterior margin of mentum, ventral view: 109 – Alienocacculus neftensis (Olexa, 1984); 110 – Ammostyphrus cerberus Reichardt, 1924; 111 – Axelinus ghilarovi Kryzhanovskij, 1976; 112 – Chalcionellus amoenus (Erichson, 1834); 113 – Chivaenius kryzhanovskii Olexa, 1980; 114 – Ctenophilotis chobauti (Théry, 1900); 115 – Eopachylopus ripae (Lewis, 1885); 116 – Eremosaprinus vlasovi (Reichardt, 1941); 117 – Euspilotus (Neosaprinus) perrisi (Marseul, 1872); 118 – Exaesiopus grossipes grossipes (Marseul, 1855); 119 – Gnathoncus rotundatus (Kugelann, 1792); 120 – Hypocaccus (Hypocaccus) rugiceps (Duftschmid, 1805); 121 – Hypocaccus (Baeckmanniolus) dimidiatus dimidiatus (Illiger, 1807); 122 – Hypocacculus (Hypocacculus) metallescens (Erichson, 1834); 123 – Hypocacculus (Colpellus) praecox (Erichson, 1834); 124 – Hypocacculus (Nessus) rubripes (Erichson, 1834); 125 – Microsaprinus therondianus (Dahlgren, 1973); 126 – Myrmetes paykulli Kanaar, 1979; 127 – Paravolvulus ovillum (Solskij, 1876); 128 – Philothis (Philothis) arcanus Reichardt, 1930; 129 – Philothis (Atavinus) atavus (Reichardt, 1931); 130 – Philothis (Farabius) hexeris Reichardt, 1930; 131 – Pholioxenus phoenix (Reichardt, 1930); 132 – Reichardtiolus duriculus (Reitter, 1904); 133 – Saprinillus paromaloides Kryzhanovskij, 1974; 134 – Saprinus (Saprinus) semistriatus (Scriba, 1790); 135 – Saprinus (Hemisaprinus) subvirescens (Ménétries, 1832); 136 – Saprinus (Phaonius) pharao (Marseul, 1855); 137 – Styphrus corpulentus Motschulsky, 1845; 138 – Turanostyphrus ignoratus Tishechkin, 2005; 139 – Xenonychus tridens (Jacquelin-Duval, 1852); 140 – Xenophilotis choumovitchi (Thérond, 1965); 141 – Zorius funereus (Schmidt, 1890).

Figs.453–461.Hypocaccus (Baeckmanniolus) dimidiatus dimidiatus (Illiger, 1807), SEM micrographs:453 – habitus, dorsal view; 454 – ditto, ventral view; 455 – antennal club, dorsal view; 456 – head, dorsal view; 457 – ditto, ventral view; 458 – prosternum; 459 – lateral disc of metaventrite, metepisternum and fused metepimeron; 460 – protibia, ventral view; 461 – ditto, dorsal view.

Figs. 462–470. Hypocaccus (Baeckmanniolus) dimidiatus dimidiatus (Illiger, 1807), male terminalia: 462 – 8th sternite and tergite, ventral view; 463 – ditto, dorsal view; 464 – ditto, lateral view; 465 – 9th tergite, 10th tergite, dorsal view; 466 – ditto, lateral view; 467 – aedeagus, dorsal view; 468 – ditto, lateral view; 469 – spiculum gastrale, ventral view; 470 – ditto, lateral view.

Fig. 8. Antennal club of Saprininae showing three types of sensillum.

Figs. 162–167.Euspilotus (Neosaprinus) perrisi (Marseul, 1872), variability of female pygidial sulci. Figs. 162–165 after OLEXA (1975).

Figs. 168–173. Saprininae, male terminalia, schematic: 168 – 8th sternite, ventral view; 169 – 8th sternite and tergite, dorsal view; 170 – ditto, lateral view; 171 – ninth tergites and tenth tergite, dorsal view; 172 – spiculum gastrale (10th sternite), ventral view; 173 – aedeagus, dorsal view.

Fig. 3. Saprininae, head, dorsal view, schematic.

Figs. 444–452. Hypocaccus (Hypocaccus) rugiceps (Duftschmid, 1805), male terminalia: 444 – 8th sternite and tergite, dorsal view; 445 – ditto, ventral view; 446 – ditto, lateral view; 447 – 9th tergite, 10th tergite, dorsal view; 448 – ditto, lateral view; 449 – aedeagus, dorsal view; 450 – ditto, lateral view; 451– spiculum gastrale, ventral view; 452 – ditto, lateral view.

Figs. 47–73. Saprininae, labral structures, dorsal view (left half showing external and right half showing internal structures): 47 – Alienocacculus neftensis (Olexa, 1984); 48 – Ammostyphrus cerberus Reichardt, 1924; 49 – Chalcionellus amoenus (Erichson, 1834); 50 – Chivaenius kryzhanovskii Olexa, 1980; 51 – Eopachylopus ripae (Lewis, 1885); 52 – Eremosaprinus vlasovi (Reichardt, 1941); 53 – Euspilotus (Neosaprinus) perrisi (Marseul, 1872); 54 – Exaesiopus grossipes grossipes (Marseul, 55); 55 – Gnathoncus rotundatus (Kugelann, 1792); 56 – Hypocaccus (Hypocaccus) rugiceps (Duftschmid, 1805); 57 – Hypocacculus (Hypocacculus) metallescens (Erichson, 1834); 58 – Hypocacculus (Colpellus) praecox (Erichson, 1834); 59 – Hypocacculus (Nessus) rubripes (Erichson, 1834); 60 – Microsaprinus therondianus (Dahlgren, 1973); 61 – Myrmetes paykulli Kanaar, 1979; 62 – Paravolvulus lateristriatus (Solskij, 1876); 63 – Philothis (Philothis) arcanus Reichardt, 1930; 64 – Philothis (Atavinus) atavus (Reichardt, 1931); 65 – Philothis (Farabius) hexeris Reichardt, 1930; 66 – Pholioxenus phoenix (Reichardt, 1930); 67 – Reichardtiolus duriculus (Reitter, 1904); 68 – Saprinus (Saprinus) semistriatus (Scriba, 1790); 69 – Saprinus (Hemisaprinus) subvirescens (Ménétries, 1832); 70 – Saprinus (Phaonius) pharao (Marseul, 1855); 71 – Styphrus corpulentus Motschulsky, 1845; 72 – Xenonychus tridens (Jacquelin-Duval, 1852); 73 – Xenophilothis choumovitchi (Thérond, 1965).

Figs. 160–161. Myrmetes paykulli Kanaar, 1979, mesotibia: 160 – dorsal view; 161 – ventral view.