Asycampta, Mamaev & Zaitzev, 2023

Jaschhof, Mathias & Jaschhof, Catrin, 2023, A review of Afrotropical Porricondylinae (Diptera: Cecidomyiidae), with descriptions of five new species of Asynaptini from KwaZulu-Natal Province South Africa, Zootaxa 5244 (3), pp. 261-275 : 264-265

Redefinition of Asycampta

within the Pseudocamptomyia group of genera

(A) Context. Although not explicitely stated in the publication, Mamaev & Zaitzev’s (1997) decision to associate two new Asynaptini from Somalian material with the then monotypic, Nearctic genus Pseudocamptomyia (type species: Asynapta phosphila Felt ), was presumably determined by male terminalia characters. While these authors ascribed one species ( africana ) to Pseudocamptomyia s. str., the other ( palpata ) was classified in a new subgenus, Asycampta , distinguished on three characters: the number of palpal segments, the dentition of the tarsal claws, and the outline of vein CuA. Asycampta was defined as having a foreshortened, 2-segmented palpus, toothless claws, and distinct vein CuA, whereas Pseudocamptomyia s. str. was characterized as having a long, 4-segmented palpus, unidentate claws, and indistinct vein CuA. While Mamaev & Zaitzev (1997) failed to clarify the meaning of “distinct” and “indistinct” with respect to vein CuA, the other two characters were useful for separating the two subgenera. The same system ceases to work, however, when additional species are taken into consideration. In Asycampta karkloofensis sp. nov., as described below, the 1-segmented palpus (supposedly indicative of Asycampta ) occurs in combination with unidentate claws (supposedly indicative of Pseudocamptomyia ). Also, vein CuA of A. karkloofensis sp. nov. extends to the wing margin, which matches the condition found in P. phosphila , but not the situation in P. africana , in which vein CuA is evanescent apically. Likewise, in Asycampta umngeni sp. nov. the presence of a 4-segmented palpus and unidentate claws (both supposedly indicative of Pseudocamptomyia ) are associated with a vein CuA that extends to the wing margin and forms a fork with vein M 4 (whereas M 4 is purportedly absent in both Asycampta and Pseudocamptomyia ). There are basically two different options to resolve the conflict between the subgeneric definitions proposed by Mamaev & Zaitzev (1997): on the one hand, Asycampta and Pseudocamptomyia are maintained as separate subgenera/genera and then need to be defined more precisely, on the other, both names are considered as synonyms.

The situation becomes more complex with the inclusion of Zadbimyia Jaschhof & Jaschhof , a genus described from Costa Rica several years after the publication of Mamaev & Zaitzev’s (1997) paper ( Jaschhof & Jaschhof 2014). While Zadbimyia is variable regarding the characters discussed above ( Jaschhof & Jaschhof 2014, fig. 2), the basic construction of male terminalia structures is stable ( Jaschhof & Jaschhof 2014, fig. 4) and resembles that described here for three new species of Asycampta . This finding challenges the distinctness of Zadbimyia and Pseudocamptomyia (now including Asycampta ) as postulated by Jaschhof & Jaschhof (2014). The decision here to maintain all three genera as discrete, rather than to subsume both Asycampta and Zadbimyia under a broad concept of Pseudocamptomyia , is backed by male morphological indicators (see below under B). As a further argument, at least Asycampta and Pseudocamptomyia + Zadbimyia likely have long, independent evolutionary histories that began with the separation of South America and Africa some 130 MYA. The sister group relationship postulated here for Pseudocamptomyia and Zadbimyia cannot be justified by synapomorphies, also because the states of several characters in Pseudocamptomyia are beyond judgement (see below). The morphology of Zadbimyia is, compared with Pseudocamptomyia , in many respects more advanced and largely similar to that of Asycampta .

At this point Larimyia Fedotova & Sidorenko must be mentioned, a monotypic genus of Asynaptini occurring in the eastern Palearctic Region, the wing and terminalia of which ( Fedotova & Sidorenko 2007, figs 84, 93) are reminiscent of the genera under discussion here. The original description does not, however, provide sufficient detail to permit any conclusions regarding the systematic position of Larimyia .

(B) Definitions.The Pseudocamptomyia groupofgenera(synapomorphiesunderlined): Asycampta , Pseudocamptomyia and Zadbimyia form a generic group that differs from other Asynaptini in the following combination of male character states (females and larvae are unknown): the scape has a medial cluster of dense setae; the scutum lacks transparent windows; vein M 1+2 is always and vein M 4 usually absent; the gonostylus lacks a pectinate tooth; the parameres are merged medially to form the tegmen that is closely tied to the apex of the phallapodeme (only two species of Zadbimyia , the affiliation of which is disputable, have separate parameres); the structural complex made of tegmen and phallapodeme is equipped with processes and lobes of varying size, shape and orientation. Asycampta . Flagellomeral necks lack microtrichia; circumfila are irregularly, strongly looped. Both labellum and palpus are atrophied; the palpus, which is markedly shorter than the head height, has one to four setaebearing segments. Basitarsal spines are present. The gonostylar apex is either unmodified, equipped with a bunch of large microtrichia (spines), or reinforced by strong sclerotization and then without microtrichia. The geographical distribution is exclusively Afrotropical. The definition given here differs from that by Mamaev & Zaitzev (1997) for it emphasizes the distinctions separating Asycampta from both Zadbimyia and Pseudocamptomyia .

Zadbimyia . Flagellomeral necks are, in most of the species, partly or entirely microtrichose; circumfila are irregularly, strongly looped. Both labellum and palpus are atrophied; the palpus, which is markedly shorter than the head height, has one to four setae-bearing segments. Basitarsal spines are present. The gonostylar apex is variously, densely microtrichose, with conspicuously large microtrichae (spines) being absent. The geographical distribution is exclusively Neotropical.

Pseudocamptomyia . Flagellomeral necks lack microtrichia; circumfila are slightly sinuous. The palpus has four setae-bearing segments; its length, as well as the structure of the labella, are unknown, due to the poor condition of available specimens. Basitarsi have a microtrichose apical projection rather than a spine. The gonostylar apex is possibly equipped with one or several small spines, which cannot be decided from existing specimens. The geographical distribution is exclusively Nearctic.

(C) Discussion. Besides Asynapta and Camptomyia , the Pseudocamptomyia group of genera represents a further extraordinarily speciose and complex subset of Asynaptini . One of the included genera, Zadbimyia , is remarkable for its regional and local diversity, with 47 species, both named and unnamed, known to be present in Costa Rica, including 35 species known to occur at a single site of cloud forest ( Jaschhof & Jaschhof 2014; unpublished data). The fact that the genus has not yet been found outside Costa Rica is certainly due to the shortage of surveys targeting Porricondylinae in the Neotropics. There is every indication that Asycampta plays a similar role in the Afrotropics. The three species described here as new were found co-occurring at a single site, and en passant rather than through targeted search. The same is true for the two species (including A. africana (Mamaev & Zaitzev) comb. nov.) described from Somalia. As a further indication of Asycampta ’s diversity, the five species now known of the genus exhibit great morphological complexity, which is comparable to that found in Zadbimyia . A number of issues regarding the Pseudocamptomyia group remain unresolved for the time being. It remains to be shown, for example, whether Pseudocamptomyia is exclusively Nearctic in distribution and as poor in species as present data suggest; whether Larimyia is a representative and if so the only representative of this genus-group in the Palearctic Region; whether Asycampta expands into the Oriental Region or whether the Pseudocamptomyia group has a different, yet unknown branch in that part of the world. It is obvious that the phylogenetic and biogeographic relations within the Pseudocamptomyia group remain as vague as those within the Asynaptini as a whole ( Jaschhof & Jaschhof 2013). The single most important impediment to a better understanding of asynaptine inter-relationships is the shortage of basic taxonomic information regarding nonEuropean faunas.

(D) Identification of Asycampta using male morphology. With only five species known at the present, certain nonterminalia characters suffice for their differentiation ( Mamaev & Zaitzev 1997). Those characters may, to a large extent, be observed even in specimens stored in ethanol, meaning they are more readily accessible compared to terminalia characters, which require investigation by light microscopy. Considering the expectation that dozens of Asycampta species remain to be discovered and described, the specific diagnoses given below give major weight to terminalia structures, which in speciose genera of Asynaptini are proven to provide the only positive interspecific distinctions (e.g., Jaschhof & Jaschhof 2013, 2014).