A review of the Afrotropical Thinophilus Wahlberg, 1844 (Diptera: Dolichopodidae), with the descriptions of ten new species

Ten new species of Thinophilus Wahlberg, 1844 from the Afrotropical region are described and illustrated: T. saegeri sp. nov. from the Democratic Republic of the Congo, T. medvedevi sp. nov., T. longicercus sp. nov., T. cataractae sp. nov. and T. manambato sp. nov. from Madagascar, T. gallagheri sp. nov. and T. deemingi sp. nov. from Oman, T. sigwalti sp. nov. from Senegal, T. subpalpatus sp. nov. from South Africa, and T. fluvialis sp. nov. from Tanzania. Type material for 13 previously described Afrotropical species is examined. The genus Paralleloneurum Becker, 1902 is newly synonymized with Thinophilus (syn. nov.). As a result, the following new combinations are here established: Thinophilus cilifemoratus (Becker, 1902) comb. nov. and T. pygmaeus (De Meijere, 1916), comb. nov. The following new synonyms are proposed: Thinophilus annulitarsis Parent, 1936 with T. calopus Loew 1852; T. bipunctatus Curran, 1926 and T. maculatus Parent, 1929 with T. indigenus Becker, 1902. New records are given for some known species. Thinophilus argyropalpis Becker, 1910 and T. spinitarsis Becker, 1907 are reported from the Afrotropical Region for the first time. The number of species of the genus, known from continental Africa, Oman, Yemen and Madagascar, has increased to 30. An identification key to 29 Afrotropical species is compiled. Thinophilus versutus Haliday, 1851 and T. cilifemoratus (Becker, 1902), type species of the former genera Schoenophilus Mik, 1878 and Paralleloneurum Becker, 1902, are subsequently also included into the key, because the two species inhabit northern Africa.


Notes
The species is known by two female types from Kenya. Only one indeterminable female from Madagascar was found in the RMCA collection under the label "Thinophilus aquaticus, det. Vanschuytbroeck". The record from Madagascar (Vanschuytbroeck 1957) is most probably a misidentification.

Distribution
Kenya.

Notes
Types of Thinophilus calopus were collected from a sea coast; later the species was once reported from the National Park Albert (= Virunga), DR Congo, at a height about 1000 m above sea level, by Vanschuytbroeck (1951), far from the sea coast. RMCA collection contains three females identified by Vanschuytbroeck as T. calopus: two of them belong to the genus Tachytrechus and one specimen to an indeterminable species of Thinophilus. I think the species must be excluded from the fauna of the Democratic Republic of the Congo.
Thinophilus annulitarsis was described from a female collected on a beach at Dar Es Salam. It has never been recorded again. A male examined from Zanzibar's beach, close to the type locality of T. annulitarsis, is identical to the female holotype (examined) and original species description (Parent 1936) and to the detailed description of T. calopus by Loew (1862). One more male of this species was found at the site Mtwara, close to the Tanzania-Mozambique border. Therefore, I consider the two names as synonyms.

Notes
Four males from the National Park Albert (= Virunga), DR Congo, were found in the RMCA collection under the label "Thinophilus capensis, det. Vanschuytbroeck"; two of them belong to Thinophilus imperialis (Curran, 1924) and two to T. splendidus. The species once reported from this country by Vanschuytbroeck (1951) must be excluded from the fauna of the Democratic Republic of the Congo.

Notes
Grichanov & Mostovski (2009) examined male and female types of Thinophilus bipunctatus (NMSA) and noted that there are no principal differences from the description of T. maculatus, and the two names may be synonyms. Thinophilus bipunctatus was previously recorded from DR Congo, Namibia, and South Africa, usually from wet material (in ethanol). Unnoticed in the original description, its types have a distinct prescutellar spot in addition to six lateral spots on the mesonotum. Thinophilus maculatus was previously recorded from Gabon, Namibia and South Eastern Desert of Egypt, sometimes from females only. Both species were in fact found in the same countries as widely distributed and common T. indigenus Becker, 1902. The key characters formerly used included only colour characters, e.g., the number of dark spots on the mesonotum (Parent 1936;Grichanov 1997). The rather abundant material examined shows that this feature is variable and invisible on wet specimens. The male genitalia examined are identical in all listed specimens, corresponding with the pictures of T. indigenus from Iranian Baluchistan published by Negrobov (1978). Therefore, I consider all three names as synonyms.

Notes
This species was firstly reported from the Afrotropical Region by Grichanov (1997).

Distribution
Afrotropical: Djibouti, Yemen; Palaearctic: Egypt, Saudi Arabia. Curran, 1926 Fig. 3H Thinophilus prudens Curran, 1926: 30. Grichanov (1997) described and figured genitalia of a male from Angola under the name T. prudens, but noted that it differs from the original description of the latter species and from a male collected from Senegal in much shorter cercus, about as long as surstylus. The Angolan male belongs most probably to the new species described here as T. sigwalti sp. nov. So, Angola is excluded from the species area.

Notes
The species is known only from type female, which is remarkable in bearing two pairs of almost equal in length bristles on the scutellum. Two males and three females from the National Park Albert (= Virunga), DR Congo, were found in the RMCA collection under the label "Thinophilus quadrisetus, det. Vanschuytbroeck"; one male belongs to T. splendidus and other material to T. imperialis. The species once reported from this country by Vanschuytbroeck (1951) must be excluded from the fauna of the Democratic Republic of the Congo.

Notes
A female reported by Vanschuytbroeck (1952) from the Upemba National Park (DR Congo) was found in the RMCA collection under the label "Thinophilus rex"; it belongs to indeterminable species of Thinophilus. The species must be excluded from the fauna of the Democratic Republic of the Congo.

Notes
Material from the National Park Albert (= Virunga), DR Congo, found in the RMCA collection under the label "Thinophilus setulipalpis" and published by Vanschuytbroeck (1951) belongs to Thinophilus prudens. The species must be excluded from the fauna of the Democratic Republic of the Congo. It is known only from type locality.

Notes
The Palaearctic Thinophilus flavipalpis was included by Vanschuytbroeck (1951: 39) into the key to Afrotropical species of the genus. No material was found in European and African museums for T. flavipalpis collected in the Afrotropics. The species was excluded from this Region by Grichanov (2018). Becker, 1902 Thinophilus quadrimaculatus Becker, 1902: 49. Type locality: Egypt, Cairo. Palaearctic: Algeria, Egypt, Iran, Israel, Tajikistan, Tunisia.

Notes
The Palaearctic Thinophilus quadrimaculatus was once reported from DR Congo by Vanschuytbroeck (1951). One male and one female from this country were found in the RMCA collection under the label "Thinophilus quadrimaculatus, det. Vanschuytbroeck"; the male belongs to Thinophilus splendidus, and the female belongs to Pelastoneurus sp. The species must be excluded from the Afrotropical fauna. Parent, 1929Thinophilus tinctus Parent, 1929a: 51. Type locality: Bir Abraq (South Eastern Desert of Egypt).

Notes
Material found in the RBINS and RMCA collection under the label Thinophilus tinctus and published by Vanschuytbroeck (1952Vanschuytbroeck ( , 1957 belongs to Thinophilus cataractae sp. nov., Hercostomus sp. and Diaphorus sp. The species must be excluded from the Afrotropical fauna. It is known only from type locality from a female.

Etymology
The specific epithet is dedicated to the collector of the types, Dr M.D. Gallagher (Oman Natural History Museum, Sultanate of Oman).

Diagnosis
Thinophilus sigwalti sp. nov. is similar to T. prudens, differing in short cercus, about as long as surstylus, short dorsal setae on fore tibia, about as long as tibia width, yellow ventral bristles and setae on fore femur and tibia, wing with distal part of M 4 at least 2 × as long as dm-m. The male of T. prudens has a very long cercus, about 2 × as long as the surstylus, a very strong posterodorsal bristle on the fore tibia, more than 2 × as long as the tibia width, partly dark or black ventral bristles and setae on the fore femur and tibia, wing with distal part of M 4 about as long as dm-m.
Both T. sigwalti sp. nov. and T. prudens are also close to T. cilifemoratus, differing in the following characters: fore coxa mostly yellow, black at base; mid and hind coxae black, yellow at apex; male fore femur with long ventral bristles, 2 × as long as femur height; hind tibia with anterior, ventral and posterior rows of elongated setulae and 1 preapical dorsal seta. Males of Thinophilus cilifemoratus were described with all coxae yellow; fore femur with hairs ("Haaren", nec "Borsten"), longer than femur height; fore tibia with only 2 posterodorsal bristles; mid femur ventrally with only light hairs; hind tibia with only ventral row of elongated setulae and 1 dorsal seta at basal ⅓, without apical setae; wing with distal part of M 4 about 1.5 × as long as dm-m; male cercus short, stick-shaped (Becker 1902;Negrobov 1979).  Curran, 1926).

Holotype
Legs. Fore coxa mostly yellow, black at base; mid and hind coxae black, yellow at apex; legs mostly yellow; fore tibia on distal half and base of basitarsus brownish; tarsi brown-black from tip of basitarsus.
Thinophilus saegeri sp. nov. is also close to the Thinophilus cilifemoratus complex, differing in the following characters: femora mostly brown; coxae with black setae and bristles; fore femur with few short black setae at base, half as long as femur height; hypopygium with black cercus. Thinophilus cilifemoratus male has the following characters: femora yellow; coxae with yellow setae and bristles; fore femur with partly doubled ventral setae, longer than femur height; hypopygium with yellow cercus (Becker 1902;Negrobov 1979;Grootaert & Meuffels 1998).

Holotype
Legs. Fore coxa brownish yellow; mid and hind coxae black; legs mostly brownish yellow; femora darker and tibiae lighter; tarsi brown-black from tip of basitarsus.
abdoMen. Shining green-black dorsally, weakly dusted; shining blue-violet laterally; tergites 2-4 ventrally whitish pollinose; setae and hind-marginal bristles black, short; sternites 3 and 4 of male abdomen with tuft of mainly black long hairs. Hypopygium (Fig. 9E-F) black with black appendages; epandrial lobe reduced to small subtriangular projection, glabrous; hypandrium short, fused with epandrium, apically concave; phallosoma narrow, weakly projected; phallus long and simple, concealed; surstylus flat and broad, at middle slightly wider than at base (lateral view), with several short inner and ventral bristles at base, with few short outer bristles at apex; cerci dorsally separated, very long, extending to base of abdomen, broad on basal third, filiform distally, with marginal bristles (Fig. 9E; distal half of cercus broken).

Female
Unknown.

Diagnosis
The small-sized Thinophilus deemingi sp. nov. is remarkable, having modified fore tarsus with basitarsus thick at apex; tarsal segments 2-4 short, triangular, with black lateral setae; segment 5 rounded, widened and flattened. As a whole, fore tibia ⅓ × as long as fore tarsus. In addition, wing crossvein dm-m ½ × as long as distal part of M 4 . Other species of the Thinophilus indigenus group have practically simple fore tarsus, longer than fore tibia; wing crossvein dm-m as long as or ⅔ × as long as distal part of M 4 .

Female
Unknown. Diagnosis Thinophilus manambato sp. nov. is close in habitus to T. capensis, T. cataractae sp. nov. and T. fluvialis sp. nov. (see key above), differing in fore coxa with mainly white setae, with at most 2-3 black apical bristles; mid coxa with white setae and one black bristle. The last three species have fore coxa with mainly black bristles and setae; mid coxa with black bristle and setae. The hypopygium of T. manambato is similar to that in T. fluvialis, but the surstylus of the latter is thin (lateral view), bearing about seven short spine-like apicoventral setae; the surstylus of T. manambato is broad (lateral view), with simple ventral and apical setae.
Legs. Fore coxa yellow; mid and hind coxae black, yellow at apex; legs mostly yellow; tarsi gradually darkened from tip of basitarsus.

Unknown.
Thinophilus fluvialis sp. nov. urn:lsid:zoobank.org:act:07D13005-A8FF-41E2-B35A-EDACC244BAE7 Fig. 12 Diagnosis Thinophilus fluvialis sp. nov. is close in habitus to T. manambato sp. nov., differing in fore coxa with mainly black bristles and setae; mid coxa with black bristle and setae. The last species have fore coxa with mainly white setae, with at most 2-3 black apical bristles; mid coxa with white setae and one black bristle. The hypopygium of T. manambato is similar to that in T. fluvialis, but the surstylus of the latter is thin (lateral view), bearing about seven short spine-like apicoventral setae; the surstylus of T. manambato is broad (lateral view), with simple ventral and apical setae. Thinophilus fluvialis keys to T. cataractae sp. nov. (see key above), differing in colour of the antenna, palp, and in morphology of hypopygium.

Etymology
The specific epithet refers to the 'riverine' inhabitation of the male type collected. Description Male (Fig. 12A) MeasureMents. Body length 3.1 mm; antenna length 0.7 mm; wing length 2.8 mm; wing width 0.8 mm.

Etymology
The specific epithet 'cataractae'(in Latin) refers to the Niagarakely waterfalls locality in the Niagarakely Forest, where the male type was collected.  Paratype MADAGASCAR • 1 ♂; same collection data as for holotype; RBINS.

Diagnosis
Thinophilus medvedevi sp. nov. is very close in size and habitus to T. quadrisetus known by female holotype from Tanzania (Dar Es Salam), differing from the latter in lateral bristles on scutellum, ⅓ to ½ as long as median bristles. The scutellum of T. quadrisetus bears two pairs of scutellars of almost equal length (Parent 1936). There are some fine differences between the species in colour characters and leg setation that may relate with individual variability. Thinophilus medvedevi keys to T. subpalpatus sp. nov., differing in mid femur with rows of ventral setae, half as long as femur height; tarsomere 5 of all tarsi deep black; tarsomeres 1-4 of fore and mid tarsi yellow. The male of T. subpalpatus has mid femur with row of ventral setae on distal half, 2 × as long as femur height; tarsi gradually darkened towards tips.

Female
Similar to male except lacking male secondary sexual characters. Posteroventral preapical setae on fore femur weakly developed; fore tarsus without white ventral pile.

Female
Similar to male except lacking male secondary sexual characters. Dyte & Smith (1980) listed 23 species of Thinophilus in their Afrotropical Catalog. Later a new species and a new subspecies were described (Grichanov 1997), many new records were published, and Grichanov (2018) listed 24 species and one subspecies in his Catalog, excluding Thinophilus flavipalpis from the Afrotropics. As a result of the present research, ten new species of the genus are described, three species names are synonymized, and four species are excluded from the Afrotropical Region. Old records of some species from DR Congo, Sudan and Madagascar are shown here to be incorrect. At the same time, I did not treat unassociated females from Botswana, Ethiopia, Malawi and Namibia, which may belong to undescribed species. Thinophilus indigenus is widely distributed in the Oriental Region and subtropics of the Palaearctic Region, being rather common in the Afrotropics, including 18 continental countries, as well as Aldabra, Madagascar, Comoros and Cape Verde Islands. Thinophilus spinitarsis Becker, 1907, if not misidentified, is also reported from the three regions, i.e., Afrotropical (Senegal), Oriental (Taiwan) and Palaearctic (Middle East, Central Asia and Black Sea coast near Kherson city). Thinophilus argyropalpis is found in Afrotropical (Senegal) and Palaearctic countries (North Africa, south-eastern Europe, Middle East and Central Asia). Thinophilus mirandus Becker, 1907 is known from Tanzania and southern Palaearctic. Thinophilus ochripalpis Becker, 1910 is found in Somalia, Tanzania, Afrotropical and Palaearctic sectors of the Arabian Peninsula. Thinophilus promotus Becker, 1910 inhabits the Red Sea coast within its Afrotropical and Palaearctic sectors. Thinophilus spinulosus Parent, 1929 is also found in arid countries of Afrotropics (Nigeria and Somalia) and Palaearctic (Egypt and Saudi Arabia). Thinophilus imperialis is reported from 10 Afrotropical countries, and T. palpatus from 9 countries.

Discussion
The Afrotropical Thinophilus is more diverse in Tanzania (eleven species), being confined mainly to the Indian Ocean coast. Nevertheless, the East African mangroves (as well as the West-Central African mangroves) are still poorly studied, and more species of Thinophilus are expected to be collected there. For example, 21 species of Thinophilus are known from small territory of Singapore, being common in mangroves (Grootaert 2018). Ten species of the genus are known in South Africa. Sixteen countries contain only one species of Thinophilus; however, these records belong mainly to widespread T. indigenus, T. imperialis and T. palpatus. Grootaert (2018) defined five species groups of Thinophilus based on highly diverse MSSC, but he did not mention the number of dorsocentrals and the position of arista, apparently considering these characters variable. The following mostly somatic features were used by Grootaert to define his species groups: The spinatus group: long slender legs with the base of the femora spindle-shaped dilated; face and mouthparts are somewhat elongate; very short vertical bristles. The simplex group: small species (2-3 mm) with short legs. The murphyi group: medium-sized to large robust species with large mouthparts; arista is partly white on the apex. The comatus group: fore and mid legs bearing very long bristles (MSSC?). The nitens group: medium-sized to large robust species; white curly hairs present on fore coxa and femur (MSSC?).
It seems that at least some MSSC are unconnected with somatic characters, e.g. modified tarsomeres, modified bristles on legs, cerci free or fused partly or fused over the entire length (Grootaert 2018).
Regarding the Afrotropical species, it is worth noting that they are also highly diverse in size (1.7-7.0 mm), colouration and morphology including such MSSC as spindle-shaped femora, partly white arista on the apex, long bristles on some podomeres. The groups and subgroups of Afrotropical Thinophilus species may be summarized as follows. Characters that occur in other species are as follows: completely grey pollinose body; light yellow antenna; nearly apical arista-like stylus, yellow basally, and white distally; mesonotum with four dorsocentrals of almost equal length; scutellum with two marginals; tibiae with short bristles; fore and mid tarsomeres shortened; surstylus bilobed; cerci separated, short, stick-shaped.

List of Afrotropical groups, subgroups and species included
Species with usually four dorsocentral bristles of almost equal length on mesonotum form two poorly defined subgroups of the Thinophilus versutus species group. All species are small-sized (1.7-2.5 mm), having straight wing vein M 1+2 ; long and slender legs; narrow surstylus formed of fused lobes; short, narrow and mostly separated cerci.
The Thinophilus versutus subgroup of species has adults with darker body, legs and antennae; poorly setose femora and tibiae; usually dorsoapical arista. It includes Afrotropical T. saegeri sp. nov. and T. cataractae sp. nov. and Palaearctic T. versutus.
The Thinophilus cilifemoratus subgroup of species has adults with lighter body, legs and antennae; rows of long ventral bristles or setae on fore tibia, fore and hind femora; well developed dorsal bristles on tibiae; usually dorsal arista. It includes Afrotropical T. prudens and T. sigwalti sp. nov. and T. cilifemoratus described from Egypt and later reported from India, Bangladesh and Taiwan. This subgroup may be related with the Oriental T. simplex group (Grootaert 2018) and other Oriental and Australasian species with four dorsocentrals described previously in the subgenus Schoenophilus (e.g., Grootaert & Meuffels 1984).
The species with five and more dorsocentral bristles on mesonotum, gradually or abruptly decreasing in length anteriorly, have almost always a weak sinuation on the wing vein M 1+2 ("wing boss") and strong apical and preapical bristles on the tibiae. They can be divided into two groups: species with fine yellow setae on palpus (Thinophilus calopus group), and species with black setae on the palpus (Thinophilus indigenus group).
The Thinophilus calopus group includes two subgroups of species. All species of this group possess white arista on their distal part (like in species of the Oriental T. murphyi group, some other Oriental and Palaearctic species). The Thinophilus calopus subgroup includes T. calopus, T. argyropalpis and T. virgatus with a scutellum bearing two hair-like lateral setae. Their body length varies from 3 mm (T. argyropalpis) to 6 mm (T. virgatus).
The Thinophilus quadrisetus subgroup includes T. quadrisetus, T. medvedevi sp. nov. and T. subpalpatus sp. nov. with a scutellum bearing two strong lateral bristles, more than half as long as major bristles, as well as T. munroi (two subspecies with 3 to 8 pairs of strong marginal spines in addition to one pair of long scutellar bristles). Their body length is 4 to 6 mm. In Singapore, only large-sized T. meieri Grootaert & Evenhuis, 2018 (from the T. murphyi group) has a scutellum with a lateral bristle at each side half as long as median marginals.
The Thinophilus indigenus group cannot be divided into well-defined subgroups of species; however, these loose assemblages are listed.
Thinophilus imperialis subgroup. Large-sized (5.5-7 mm) T. imperialis, T. ciliventris and T. longicercus sp. nov. are distinguished by the tuft of long hairs on sternites 3 and 4 of the abdomen. Their male surstylus is broad, strongly sclerotized, with fused lobes. Thinophilus imperialis and T. longicercus sp. nov. have extremely long and thin cerci extending to the base of abdomen. The group seems to be monophyletic.
Thinophilus indigenus subgroup. Four species with distinct dark lateral spot at notopleura, with postalar dark spot, with or without dark spot in front of scutellum: T. indigenus, T. rex, T. setulipalpis and T. splendidus. Their body length is 2.5 (T. indigenus) to 5.8 mm.
Thinophilus ochripalpis subgroup. Other Afrotropical species of the Thinophilus indigenus group have mesonotum monochrome, or with longitudinal stripes dorsally, without dark lateral spots, rarely with postalar dark spot. This is a rather loose group of species of variable size (3.1-5.5 mm) and MSSC: T. capensis, T. fluvialis sp. nov., T. manambato sp. nov., T. mirandus, T. ochripalpis, T. palpatus, T. promotus and T. spinitarsis. Some species possess white arista on its distal part, like species of the Oriental T. murphyi group having also black setae on palps.
Thinophilus deemingi sp. nov. is small-sized (body length 1.8 mm) and is regarded as a different subgroup of the Thinophilus indigenus group, differing from other species in long distal part of wing vein M 4 , two × as long as crossvein dm-m; shortened male fore tarsus (with fore tibia ⅓ longer than fore tarsus) with tarsal segments 2-4 short, triangular, and segment 5 rounded, widened and flattened; cerci dorsally fused almost to apex, boat-shaped. Other species of the Thinophilus indigenus group have practically simple fore tarsus, longer than fore tibia; wing crossvein dm-m as long as or ⅔ as long as distal part of M 4 ; differently shaped cerci, fused at most in basal part, rarely adjoined.
As a result of this research, the number of species of the genus has increased to 30, known from continental Africa, Oman, Yemen and Madagascar. The real number of species of Thinophilus may be much larger than 50 in this area.