Orthomus dimorphus Antoine, 1933

Serrano, J., 2021, The genus Orthomus Chaudoir, 1838 in the Iberian Peninsula and Morocco, Russian Entomological Journal 30 (4), pp. 430-447 : 441-442

Orthomus dimorphus Antoine, 1933

Figs 71–76 .

This species has two subspecies, O. dimorphus antoinei Mateu, 1955 and O. dimorphus dimorphus Antoine, 1933 . The following description is based on the first one, that is more common in Atlantic Morocco than the nominal subspecies, that is restricted to some localities of Great Atlas over 2000 m.a.s.l.

Dorsum dark brown, appendices brown, male shiny, female mat, microreticulation well visible in females, weak in males. Body length variable within populations and between subspecies, 7.0–12.0 mm. Eyes moderately convex and protruding, tempora long.

Pronotum somewhat trapezoid, maximum width after middle ( Fig. 71 ), side curved and narrowed forward, only narrowed backward near posterior angle; this shows a small protruding tooth; posterior basis beaded up to inner linear fovea; external fovea variably impressed; punctures variable in density and size, usually fine and in moderate density; postangular field convex.

Elytra slightly widened from basis; humerus with a small and non-protruding tooth, parascutellar stria well-developed with proximal seta; striae smooth but with traces of punctures; intervals flat.

Prosternal process somewhat rounded. Metepisterna smooth, long and narrowed backward ( Fig. 72 ). Ventral segments laterally smooth or with fine and few punctures. Male mesotibia not distally dilated; male metatibia only slightly curved and without crenulation in distal inner side.

Median lobe of aedeagus with an elongate apical shaft ( Fig. 73 ), almost evenly narrowed apicad, and almost straight in lateral view ( Fig. 74 ); membranous area notably prolonged toward the bulb.

Spermatheca notably longer than duct ( Fig. 75 ), it becomes notably thick after fertilization ( Fig. 76 ). This shape difference within the same species calls attention on the variable aspect that may take the female genitalia of Orthomus depending on matureness and fertilization.

The subspecies O. dimorphus dimorphus occupies the Great Atlas above 2000 m. Its body length is smaller (less than 10 mm), the female is mat, the pronotum basis is almost smooth, the humeral tooth is small, the striae are almost smooth, and the median lobe of aedeagus is ventrally curved upwards, with an apical shaft that forms a relatively short triangle.

The subspecies O. dimorphus antoinei is of larger body length and both sexes are dorsally shiny. The pronotum basis is punctured, the external fovea is better marked, the striae of elytron are well impressed and punctured, the humeral tooth is developed. The median lobe of aedeagus is almost straight on distal half in lateral view; in dorsal view it shows a more elongate and triangular apical shaft. This subspecies is found in the Atlantic plain of Morocco and doesn’t enter in the Rif and the Great Atlas above 2000 m. See Antoine [1957] for further details.

71

Figures

Figs 65–76. Orthomus spp, specimens from Morocco: 65–70 — O. berytensis; 71–76 — O. dimorphus antoinei; 65, 71 (in part) — habitus; 66 — posterior angle of pronotum (in part); 67 — metepisterna and ventrites (in part); 72 — metepisterna; 68–69, 73–74 — median lobe of aedeagus; 70 — spermatheca and spermathecal duct (in part); 75 — empty spermatheca of young female; 76 - full spermatheca of mature female; 65, 68, 71, 73 — dorsal view; 66 — ventral view;69, 74 — left lateral view; 72 — right lateral view; 67, 70 — Essaouira; 68–69 — Agadir; 73, 76 — Rabat (plage); 75 — Meknés. Scale bars: 1.5 mm (Fig. 71); 2.0 mm (Fig. 65). Рис. 65–76. Orthomus spp, особи иЗ Марокко: 65–70 — O. berytensis; 71–76 — O. dimorphus antoinei; 65, 71 (частично) — внеШний вид; 66 — Задний угол переднеспинки (частично); 67 — Эпистерн Заднегруди и вентриты (частично); 72 — Эпистерн Заднегруди; 68–69, 73–74 — среднЯЯ долЯ Эдеагуса; 70 — сперматека и её проток (частично); 75 — пустаЯ сперматека неполовоЗрелой самки; 76 — полнаЯ сперматека половоЗрелой самки; 65, 68, 71, 73 — сверху; 66 — сниЗу; 69, 74 — сбоку слева; 72 — сбоку справа; 67, 70 — Эс-Сувейра; 68–69 — Агадир; 73, 76 — Рабат (плЯж); 75 — Мекнес. МасШтаб: 15 мм (Рис. 71); 20 мм (Рис. 65).