Paramixogaster vespiformis ( de Meijere, 1908 )

Reemer, Menno & Sankararaman, Hariharakrishnan, 2024, Revision of the Oriental species of the hoverfly genus Paramixogaster Brunetti, 1923 (Diptera, Syrphidae, Microdontinae), ZooKeys 1208, pp. 1-48 : 1-48

Paramixogaster vespiformis ( de Meijere, 1908)

Figs 46–51 , 52–53 , 117–122 , 137

Microdon vespiformis de Meijere, 1908: 210. Lectotype ♀: Indonesia, Java ( RMNH) [examined]; Knutson et al. 1975: 372.

Paramicrodon decipiens de Meijere, 1917: 242. Holotype ♀: Indonesia, Java ( RMNH) [examined].

Paramicrodon dicipiens de Meijere, 1917 – Knutson et al. 1975: 373 (misspelling).

Paramixogaster decipiens ( de Meijere, 1917) – Reemer and Ståhls 2013 a: 145.

Paramixogaster vespiformis ( de Meijere, 1908) – Reemer and Ståhls 2013 a: 145.

Studied type specimens.

Lectotype of Microdon vespiformis de Meijere (designated here, see notes). Indonesia • 1 ♀; label 1: “ E. Jacobson Batavia Sept. 1907 ”; label 2: “ Microdon vespiformis type det. de Meijere ”; label 3 (red): “ Microdon vespiformis de Meijere, 1908 ZMAN type DIPT. 1074.1 ”; RMNH.

Indonesia • 1 ♀, paralectotype (new designation, see notes) of Microdon vespiformis de Meijere ; label 1: “ Microdon vespiformis ”; label 2: “ Microdon vespiformis de Meijere, 1908 ZMAN type? DIPT. 1074 ”; RMNH .

Holotype of Paramicrodon decipiens de Meijere. Indonesia • 1 ♀; Java; RMNH. Label 1: “ Salatiga V. 1915 Roepke ”; label 2: “ Paramicrodon decipiens det. de Meijere Type ”; label 3 (red): “ Microdon decipiens de Meijere, 1917 ZMAN type DIPT. 0975.1 ”; RMNH.

Paratypes of Paramicrodon decipiens de Meijere (only puparia, no adult specimens, although probably the holotype was reared from one of these specimens). Indonesia • 3 empty puparia on a piece of dry leaf. Label 1: “ Salatiga V. 1915 Roepke ”; label 2: “ Paramicrodon decipiens de Meijere, 1917 ZMAN type? DIPT. 0975 ”.

Additional specimens.

Indonesia • 1 ♀; Java; Apr. 1908; E. Jacobson leg.; RMNH • 1 ♀; Java, Dungus Iwul ; 2 Dec. 1952; alt. 100 m; M. A. Lieftinck leg.; RMNH • 3 ♂ 1 ♀; Sumatra, Fort De Kock ; alt. 920 m; 1925; E. Jacobson leg.; RMNH • 1 ♀; W. Bali, nr. Negara, rainforest above Batuagung ; alt. 550 m; 4–6 Dec. 1991; C. van Achterberg leg.; RMNH .

Malaysia • 1 ♂; Penang; 1927; C. F. Baker leg.; USNM • 1 ♂; Penang; 8 Dec. 1942; H. T. Pagden leg.; NHMUK [13933416] .

Philippines • 1 ♂; Palawan, Brookes, Point Uring Uring ; 16 Aug. 1961; Noona Dan. Exp. 61–62 leg.; ZMUC • 1 ♂; Palawan, Brookes, Point Uring Uring ; 10 Sep. 1961; Noona Dan. Exp. 61–62 leg.; ZMUC • 1 ♂; Palawan, Mantalingajan, Pinigisan ; 7 Sep. 1961; Noona Dan. Exp. 61–62 leg.; ZMUC • 1 ♂; Balabac, Dalawan Bay ; 8 Oct. 1961; Noona Dan. Exp. 61–62 leg.; ZMUC • 1 ♂; Balabac, Dalawan Bay ; 13 Oct. 1961; Noona Dan. Exp. 61–62 leg.; ZMUC • 1 ♀; Balabac, Dalawan Bay ; 10 Oct. 1961; Noona Dan. Exp. 61–62 leg.; ZMUC .

Thailand • 1 ♀; Chantaburi Prov., Tha Mai District, Ao Khating ; 1 Jan. 1992; G. R. Ballmer leg.; UCRC [label: “ Photo KC 64-318: 31 - 33 ”]

Diagnosis.

Body length: males 7–9 mm (n = 7), females 6–10 mm (n = 6). This belongs to the group of species without lateral bulges on the frons. From P. luxor it differs by the postpedicel being longer than the scape (shorter in P. luxor ). From P. contracta and P. conveniens it differs by the incomplete transverse suture (complete in P. contracta and P. conveniens ). From P. sacki it differs by tergites 3 and 4 being black with yellow posterior margin (yellow with pattern of black vittae in P. sacki ). It differs from P. jubata Reemer , sp. nov. by the shorter tergite 2, of which the posterior margin is wider than the median length (longer in P. jubata Reemer , sp. nov.), the dark anterior margin of the scutellum (entirely yellow in P. jubata Reemer , sp. nov.) and the shorter setulae on the vertex.

Paramixogaster vespiformis is most similar to P. indica , from which it differs by the interrupted yellow vitta between postpronotum and posterior callus (continuous in P. indica ), and the shorter postpedicel in the male, which is 3.3–3.7 × as long as the scape (4.4–5.6 × as long in P. indica ). Male: postpedicel 3.3–3.7 × as long as scape. Female: postpedicel 1.6–2.9 × as long as scape. The degree of infuscation of wing apex is very variable. Male genitalia as in Fig. 137 .

Notes.

The description of Microdon vespiformis by de Meijere (1908) was based on an unknown number of specimens. The specimen identified as syntype by de Jong (2000) is clearly a primary type, based on the label information and the concurrence of its characters with the original description. This specimen is here designated as lectotype. The RMNH collection also holds a female specimen which is considered by de Jong (2000) as a possible syntype of Microdon vespiformis de Meijere. The label is in de Meijere’s handwriting and the specimen agrees well with the other syntype, except that it is smaller (6 mm), and it has a peculiar forked appendix on vein R 4 + 5. This latter character is considered as an abnormality. Unlike the lectotype, however, this specimen has no locality information on the label. Besides, de Meijere (1908) does not mention a smaller specimen with an aberrant wing venation. Therefore, this specimen is here regarded as not belonging to the type series.

In the same paper as the one in which he described Microdon vespiformis, de Meijere (1908) also described specimens from Bali which he identified as Microdon indicus (Doleschall) . However, as de Meijere noted himself, these specimens differ from M. indicus as described by Doleschall (1857), and also from Microdon vespiformis de Meijere, 1908 , because the frons is rather uneven (‘ ziemlich uneben’) and bears two large, round elevations (‘ etwas erhabenen grossen runden Stellen’). This character reminds of the lateral bulges on the frons found in several other Paramixogaster species (e. g., P. icariiformis , P. sulawesiana Reemer , sp. nov., Fig. 6 ), but not in P. indica or P. vespiformis . Probably, the Balinese specimens referred to by de Meijere as C. indica were misidentified. Unfortunately, no specimens identified by de Meijere as C. indica could be found in the collection of the RMNH (which nowadays includes the collection of the former ZMAN, in which most of de Meijere’s material was deposited). So, the identity of Microdon indicus (Doleschall) sensu de Meijere (1908) remains unclear.

The empty puparia (Figs 52 , 53 ) listed among the type specimens of Paramicrodon decipiens de Meijere have also been described by de Meijere (1917), so these can be regarded to belong to the type series ( de Jong 2000). As the species description is based on the single adult female, thus the holotype, the empty puparia are considered paratypes.

In the holotype of P. decipiens there is no appendix on vein R 4 + 5. Otherwise, the species is very similar to the other specimens here identified as P. vespiformis . In some of the specimens from the Philippines this appendix is also lacking, whereas in one specimen it is only present in one of the wings.

Paramixogaster vespiformis is very similar to P. indica , so such an extent that these taxa might be considered synonymous as well in the future. Unfortunately, most of the available specimens are at least several decades old, so molecular analyses are not very feasible. As the morphological differences are small, but consistent, here the view is taken that these taxa represent two different, albeit closely similar species.

The separation between the ranges of P. indica and P. vespiformis seems to follow the line of Wallace, as well as Huxley’s adaptation of it ( Lohman et al. 2011), with P. indica being the Wallacean species and P. vespiformis occurring on the Sunda Shelf. The single exception seems to be a female specimen from Bali (collected near Negara rainforest, above Batuagung, 4–6. XII. 1991, leg. C. van Achterberg, coll. RMNH). The yellow lateral vitta along the scutum is continuous in this specimen, which would indicate P. indica . However, the other characters differentiating between P. indica and P. vespiformis can only be seen in males, so identification based on this single colour character remains a bit uncertain. This female specimen is here left unidentified and it is therefore not listed among the studied specimens. It would not be the first ‘ Wallacean’ taxon to colonise Bali ( Tänzler et al. 2014), but more specimens are needed to confirm that this is indeed the case.

A larva of this species was found by Greg R. Ballmer (pers. comm. 2023) in Thailand in 1992 in a folded leaf shelter, also occupied by ants, putative Dolichoderus thoracicus (Smith, 1860) (Fig. 4 ). This specimen was reared to the adult stage, and the adult specimen is mounted together with the empty puparium. See section Additional material for further details.

Distribution.

Known from Thailand, Peninsular Malaysia, the Indonesian islands Sumatra, Java and Bali, and the Philippines. From the Philippines, all specimens are from the islands Balabac and Palawan. All known localities are situated west of the Wallace Line (and also of Huxley’s adaptation of it).

Figures

Figure 4. Larva of Paramixogaster vespiformis (de Meijere), attended by ants, putatively of Dolichoderus thoracicus (Smith). Found in Thailand and reared to the adult stage by Greg R. Ballmer. For further details, see species account of P. vespiformis. Photograph by G. R. Ballmer.

Figures 46–51. Microdon decipiens de Meijere, female, holotype: 46 habitus, dorsal 47 habitus, lateral 48 head, frontal 49 head, lateral 50 head, dorsal 51 wing.

Figures 52, 53. Microdon decipiens de Meijere, puparium, paratype: 52 habitus, dorsal 53 habitus, lateral.

Figures 117–122. Microdon vespiformis de Meijere female, lectotype: 117 habitus, dorsal 118 habitus, lateral 119 head, frontal 120 head, lateral 121 head, dorsal 122 wing.

Figures 130–137. Male genitalia of Paramixogaster species: 130 P. contracta (paratype Microdon subpetiolatus Thompson) 131 P. halmaherensis Reemer, sp. nov. holotype 132 P. luxor holotype 133 P. sacki Taiwan, RMNH 134 P. sulawesiana Reemer, sp. nov. holotype 135 P. jubata Reemer, sp. nov. paratype Vietnam 136 P. indica (paratype P. wegneri Keiser syn. nov.) 137 P. vespiformis Sumatra, RMNH.

Figures 5, 6. Head, dorsolateral: 5 frons more or less even, without lateral bulges (Paramixogaster vespiformis female, Indonesia) 6 frons uneven, with lateral bulges (P. icariiformis female, neotype).