Procladius stroudi Roback, 1982

Silva, Fabio Laurindo Da, 2019, Procladius travassosi (Oliveira, Messias & Silva-Vasconcelos, 1992) regarded as a new junior synonym of Procladius stroudi Roback 1982 (Diptera: Chironomidae: Tanypodinae), Zootaxa 4555 (2), pp. 280-282 : 280-281

Procladius stroudi Roback

Procladius stroudi Roback 1982b: 122 (original description)

Laurotanypus travassosi Oliveira, Messias & Silva-Vasconcelos 1992: 410 (description of male and female); Dantas & Hamada 2018: 463 (as Procladius , description of immature stages and redescription of male). New Synonym.

The holotype and one paratype of Procladius stroudi , slide-mounted in Hoyer’s medium and deposited at the Academy of Natural Sciences of Philadelphia (ANSP), were examined. According to Oliveira et al. (1992), the types of Procladius travassosi (as Laurotanypus ) are deposited in the Entomological Collections of the Institute Oswaldo Cruz (CEIOC-RJ). However, in a recent visit to this collection G. P. S. Dantas was not able to locate either the holotype or the paratypes, which suggests that the types have been lost ( Dantas & Hamada 2018). Therefore, information on Procladius travassosi is based on the original descriptions ( Oliveira et al. 1992) and the complete redescription of the species ( Dantas & Hamada 2018). From the drawings provided by Oliveira et al. (1992), it was immediately apparent that Procladius travassosi is identical to P. stroudi . Here, the seeming synonymy is confirmed after the comparison between the redescription of the adult male by Dantas & Hamada (2018) and the type material of Procladius stroudi .

The species Procladius travassosi was diagnosed by the presence of a scutal tubercle, banded wings and the gonostylus without heel. The scutum has a well-developed tubercle, indeed. However, this feature has been also observed in other species of Procladius . The gonostylus was figured and described in some detail, but apart from the lack of heel, the species described by Oliveira et al. (1992) seems not to possess any features affording distinction from most other Procladius species. Comparing specimens ascribed to Procladius stroudi and P. travassosi , I was not able to find any valid difference between them to justify the Brazilian specimens as a separate species from Procladius stroudi . Slight differences are evident in the descriptions and some specimens examined. In the Colombian specimens, for example, the scutal tubercle is less prominent and the apices of the abdominal segments II–V are narrowly pale, while the gonocoxite is brown in the apical half. These minor divergences observed can be reasonably interpreted as differences between populations of the same species in different areas. Males of Procladius stroudi can be separated from any other Procladius (Psilotanypus) by the wings with two dark transverse bands, the reduced eye dorsomedial extension and the presence of scutal tubercle. According to Dantas & Hamada (2018), pupae of Procladius stroudi are characterized by the cylindrical thoracic horn, the rounded plastron plate and the absence of lateral fringe on the abdominal segments III–VI, while the larvae can be distinguished by the mola distally expanded with bilobed apex and the paraligula with small points in the outer and inner margins.

In a comprehensive study of the subfamily Tanypodinae, Silva & Ekrem (2016) sampled morphological characters across all life stages for all nine tribes within the subfamily. In that study, the genus Laurotanypus was recovered as a sister to Djalmabatista Fittkau in both analyses of equally weighted characters and by using implied weights. A phylogenetic analysis, based on the data of Silva & Ekrem (2016), including information about the immature stages of Laurotanypus recovered the putative genus occupying the most basal position within the tribe Procladiini (data not shown). According to the nomenclatural action proposed here, I would expect Laurotanypus to be recovered as a sister to Procladius , as these terminals are represented by different species of the latter genus. Nonetheless, the phylogenetic sister-relationship between the so-called Laurotanypus and the remaining genera in Procladiini may be attributed to the lack of character information about the unknown immature stages of Lepidopelopia Harrison and partially from Saetheromyia Niitsuma. Moreover, Silva & Ekrem (2016) , in their matrix, did not fully considered the subgeneric morphological divergence in Procladius . In addition, Dantas & Hamada (2018) reported inconsistencies in the establishment of the subgenera of Procladius , since the male of P. stroudi seems not to fit in the diagnosis of any of the three subgroups of the genus. Other than that, the boundary of some genera in the tribe Procladiini appears to become increasingly unclear with deeper sampling in recent years. In this context, the use of molecular markers may be a suitable approach for summarizing the diversity and detecting taxonomically challenging species (Silva & Wiedenbrug 2014) and species groups within Procladiini .

In relation to the ecology, in Brazil, the larvae of Procladius stroudi were collected associated with aquatic vegetation on the banks of a first order stream, characterized by acidic black water ( Dantas & Hamada 2018). In Colombia, although no immature stages were collected, the adults were found in the vicinities of the Laguna Mozambique ( Roback 1982b), which is an old cutoff oxbows of the Metica river, characterized by having the margins with decaying vegetation, and a layer of clean fine silt toward the center ( Roback & Nieser 1974). Although there is not much information about the distribution in the type-locality, Colombia, the species appears to disperse widely in Brazil, occurring from the north to the southeast, in both savanna and forest areas ( Oliveira et al. 1992).