Aphaniosoma zizense, Ebejer, Martin J., 2016

Ebejer, Martin J., 2016, The Moroccan species of Chyromyidae (Diptera) with descriptions of five new species of Aphaniosoma Becker, Zootaxa 4208 (3), pp. 221-236: 230-232

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Aphaniosoma zizense

sp. n.

Aphaniosoma zizense   sp. n.

Figs 11–13, 14 View FIGURES 11 – 15 a

Diagnosis. A yellow species with pale brownish yellow scutal vittae and well-developed presutural dorsocentral setae; transverse dark brown bands on basal half of abdominal tergites; short frontal setulae, but no pair of long setae in front of ocellar triangle; sternites 5 and 6 in the male strongly modified with externally visible projections.

Description. Male: Head: all yellow except for black ringed ocelli; almost twice as broad as long; frons narrowed anteriorly, at level of antennae 0.7 width that at level of anterior ocellus; gena narrow in front, deeper behind, in profile, below middle of eye, about equal to 1/3 height of eye, with numerous white setulae; occiput in profile narrowly visible behind eye, with pale postocular setulae irregularly in one row; mouth parts all yellow; 2 vibrissal setae, the lower stronger and in line with another 3 to 4 marginal buccal setae; face short, poorly sclerotized and depressed; median carina not developed; antenna yellow, pedicel paler than postpedicel with distinct short seta dorsally; postpedicel with fine pubescence along anterior margin shorter than diameter of basal segment of arista; 1st segment of arista yellow at base, apical half and second segment brown, with fine pubescence; chaetotaxy: 2 strong orbitals, with 3 short setulae in front of them, postverticals short and crossed; 1 medial vertical and 1 lateral vertical, both strong; ocellars long, proclinate and diverging; about 10 short setulae across middle of frons without a pair much longer than these situated in front of ocellar triangle.

Thorax: yellow; scutum with indistinct pale brownish yellow vittae, confluent anteriorly, only separating well behind transverse suture; that between dorsocentral and intra-alar line and that lateral to intra-alar line more distinct, darker and stop at level of hindmost dorsocentral; metanotum black; pleura yellow with brown marks on lower border of anepisternum, large triangular patch on middle of katepisternum and meron, and narrow anterior border on anepimeron; chaetotaxy: thoracic setae all well-developed, 1 long lateral and 1 short medial postpronotal, 1 incurved internal post-postpronotal, 1 very long presutural, 2 notopleural, 1+1 intra-alar, 1 postalar, 1+3 dorsocentral, 4 acrostichals with prescutellars only slightly longer, 4 scutellars, 1 anepisternal with 2 setulae below it, 1 katepisternal at upper posterior corner with 4 setulae vertically down middle of sclerite.

Wing: veins all pale yellow; distance on costa between R2+3 and R4+5 about 0.4 that between R4+5 and M; distance between cross veins about 1.8 times length of posterior cross vein, which lies slightly oblique and is about 0.3 length of apical section of vein Cu. Haltere pale yellow.

Legs: yellow, not modified except for slightly thicker femora; numerous pale setulae scattered on all pairs of legs, in addition longer setulae present on fore femur; apico-ventral seta on mid tibia brown; claws black in apical 2/3 and pulvilli normal; 5th tarsal segment of all legs pale brown; hind trochanter ( Fig. 14 View FIGURES 11 – 15 a) with barely discernible tubercle on posteromedial corner bearing about 6 minute hairs.

Abdomen: basal 4 tergites yellow with dark brown transverse bands dorsally; tergite 5 and 6 yellow; tergites with relatively few fine pale brown setulae especially along posterior margins.

Postabdomen ( Figs 11–13 View FIGURES 11 – 15 ): epandrium very small and pale, bearing long surstylus, cerci fused and pale, hypandrium distinct but pregonite indistinct, phallapodeme triangular with large anterior process, basiphallus very large, postgonites very short, narrow, brown and apposed close to distal end of basiphallus; distiphallus elongated, pale, mostly membranous.

Female: identical to male except for secondary sexual characters on postabdomen.

Variation: in both sexes, but more so in females, the scutal vittae can be dark, setulae especially on the frons longer and more numerous; acrostichals may be in 5 to 6 pairs and irregular. Some males appear to have a hind trochanter without a tubercle.

Body length: male 2 mm, female 2.1 mm, Wing length: male 1.6 mm, female 1.7 mm.

Etymology. The species epithet refers to the river Ziz where the species was collected.

Material. Holotype: male, SE High Atlas, Errachidia, Oued Ziz, 31°58.841ʹN 04°27.592ʹW, 1052 m, 3.v.2012, MJE (registration number: NHMUK010579843). Paratypes: 10♂ 14♀, same data and depository except 3♂ 3♀, in the Institute of Science, Rabat, Morocco and 3♂ 5♀, in MJE collection   ; 1♀, SE High Atlas, El-Hajeb, 9.5 km SE of Rich, Ziz River , 32°15.693ʹN 04°24.749ʹʹW, 1285 m, 29.iv.2012, MJE ( NHMUK)   ; 1♂ 6♀, Errachidia, 10 km S of Errachidia, Ziz River , 31°53.945ʹN 04°20.188ʹW, 1008 m, 1.v.2012, MJE ( NHMUK)   .

Similar species. The new species belongs to the A. collini   species group with strong presutural dorsocentral setae. Some of the species in this group also have a presutural intra-alar seta and many of them also exhibit a modified hind trochanter in the male. The new species differs from related species in the shape of the hind trochanter and details of the male postabdomen, in particular the highly modified sternites 5 and 6. The species closest to A. zizense   is A. harteni Ebejer, 1996   , described from Yemen. I consider these two to be sibling species. In A. harteni   the sternites 5 and 6 are differently shaped ( Fig. 15 View FIGURES 11 – 15 ), the anterior process of the phallapodeme is shorter and a little curved postero-dorsally and the basiphallus shorter and narrower; the fifth tarsomere is quite black in A. harteni   but only brownish in A. zizense   . The paratype of A. harteni   that was dissected for this comparison was stored in glycerin and is not in good condition. The distiphallus though discernible was not clear enough to allow good illustration. As in A. zizense   , the pregonites could not be made out. The hind trochanter of A. harteni   does have a small projection ( Fig. 14 View FIGURES 11 – 15 b), not as stated in the original description. This character may be unstable, or developed to a variable degree in this species as it is in A. zizense   . Further detailed study of this species group is required to elucidate some of the hypopygial structures, but this is beyond the scope of this paper.


Natural History Museum, London