Philonthus arrowianus Bernhauer 1931
Creators: name: Hromádka, Lubomír
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Philonthus
Philonthus arrowianus

description: Philonthus arrowianus Bernhauer, 1931   
(Figs. 1–5)  
 Philonthus arrowianus Bernhauer, 1931: 585.   
 Type locality. Ethiopia, Mt. Zik’wala, ca. 2745 m a.s.l.   
 Type material examined. LECTOTYPE (here designated): J, ' Abyssinia, Mt. Zuquala, circa 9,000 ft. // Brit. Mus 1927-121 // 22.X.1926, Dr. H. Scott // Chicago NHMus, M. Bernhauer collection // arrowianus Bernh. Cotyp. // Philonthus arrowianus Bernh. Cotypus’ (FMNH).   
 Redescription. Body length 11.1 mm, length of fore body (to end of elytra) 5.1 mm.   
Colouration. Head black, maxillary palpi, labial palpi and antennae dark brown, base of antennomere 2 brown-yellow, pronotum and scutellum black-brown, elytra brown-red with sides vaguely darker, abdomen dark brown, with a clear rainbow iridescence, posterior margins of all tergites narrowly brown-red, femora and tarsi brown-yellow, tibiae darker.  
Head slightly wider than long (ratio 32: 30), parallel-sided, posterior angles rounded, each bearing one long and several shorter bristles. Four coarse punctures between eyes, distance between medial interocular punctures four times the distance between medial and lateral interocular puncture, lateral punctures slightly shifted anteriad. Eyes shorter than temples (ratio 12: 14). Three coarse punctures situated along medial margin of eye in its posterior half. Temporal area densely punctate. Surface without microsculpture.  
Antennae slender and long, reaching posterior margin of pronotum when reclined. All antennomeres longer than wide. Relative lengths of antennomeres: 1 = 12; 2 = 6.5; 3 = 8; 4–7 = 5.5; 8–10 = 5; 11 = 6.  
Pronotum highly convex, slightly longer than wide (ratio 44: 41), inconspicuously narrowed anteriad. Anterior angles conspicuously deflexed, vaguely obtusely rounded. Left dorsal row with six punctures, right row with seven punctures. Punctures 1–5 approximately equidistant, distance between punctures 5 and 6 shorter than distance between previous punctures. Each sublateral row with two punctures. Surface without microsculpture.  
Scutellum coarsely and very densely punctate, diameter of punctures somewhat larger than eye facets, distance between punctures very small.  
Elytra combined wider than long (ratio 54: 49), slightly widened posteriad. Punctation coarse and sparse, punctures larger than eye facets, separated by 1.0–1.5 puncture diameters in transverse direction. Surface without microsculpture; setation light brown.  
Legs. Metatarsus as long as metatibia, relative lengths of metatarsomeres: 1 = 8; 2 = 6; 3 = 5; 4 = 4; 5 = 8.  
Abdomen wide, parallel-sided, very slightly narrowed posteriad beginning with visible tergite V. First three visible tergites with two basal lines, elevated area between lines densely punctate. Punctation of visible tergites very fine and very dense; punctures smaller than eye facets, separated by distance smaller than diameter of punctures, becoming sparser towards posterior margin of each tergite. Surface without microsculpture; setation similar to that on elytra.  
Male. Protarsomeres 1–3 strongly dilated and sub-bilobed, each covered with modified pale setae ventrally, protarsomere 4 distinctly narrower than preceding ones. Sternite VIII (Fig. 4), sternite IX (Fig. 5), aedeagus (Figs 1–3).  
Female. Unknown.  
 Differential diagnosis. Philonthus arrowianus may be distinguished from the similar P. meges by a narrower head, longer eyes and different shape of the aedeagus.   
 Distribution. Ethiopia.   
 Note. The species was described from two specimens, one from Mt. Zik’wala and one from Mt. Ch’ilalo, situated ca. 80 km apart. I have examined only the former specimen, which is hereby designated as the lectotype.
description: Published as part of Hromádka, Lubomír, 2010, A revision of the Afrotropical species of the Philonthus arrowianus species group (Coleoptera: Staphylinidae: Philonthina), pp. 131-144 in Acta Entomologica Musei Nationalis Pragae 50 (1) on pages 132-133, DOI: 10.5281/zenodo.5325118