Redescription of the male of Pelecorhynchus vulpes (Macquart) and first description of the male terminalia (Diptera: Pelecorhynchidae)

. Macquart (1850) provided the original description of Pelecorhynchus vulpes (= Pangonia vulpes ) based on a holotype male from Chile. His description is brief and lacks many morphological details. Therefore, herein we redescribe, in far greater detail, the holotype male of Pelecorhynchus vulpes (Macquart) and describe and illustrate, for the first time, the morphology of the male terminalia.


INTRODUCTION
described the genus Pelecorhynchus on the basis of the Australian species P. maculipennis Macquart.However, later studies synonymized this species with P. personatus (Walker), which Walker (1848) originally described from Australia without reference to any species being known from the New World.Later, Bigot (1857) erected the genus Coenura, which includes the species of Chilean distribution.Coenura and Pelecorhynchus are both genera of which were placed in the subfamily Pelecorhynchinae of Tabanidae (Enderlein, 1925).Later, Mackerras & Fuller (1942) elevated the group to family rank and considered Coenura as a junior synonym of Pelecorhynchus on the basis of morphological similarities of adults.Recently, González et al. (2023) restored Coenura Bigot, 1857 to generic status to include part of the southern South American fauna comprised of C. biguttata Philippi, C. elegans Philippi, C. hualqui (Llanos & González), C. longicauda Bigot, C. toltensis (Llanos & González), and C. xanthopleura Philippi.The monophyly of this group is supported by molecular and morphological data and is consistent with a strictly Chilean distribution (González et al., 2023).Chilean species maintained within Pelecorhynchus, includes P. vulpes (Macquart), P. kroeberi (Lindner) and P. penai Pechuman.Chilean species of Pelecorhynchus form a clade that includes the type species P. personatus (González et al., 2023).
Pelecorhynchus flies currently are known to occur in southeastern Australia, including Tasmania (Daniels, 1989), as well as in the central and southern regions of Chile (Llanos et al., 2015;González & Elgueta, 2020).These flies feed on nectar and frequently are associated with flowers, especially during spring.
Pelecorhynchus vulpes (Macquart, 1850) was described on the basis of a male holotype collected in Chile.In his original description, Macquart referred the specimens to "Chili", collected by "M.Gay" (= Claude Gay).Indeed, Claude Gay is known to have collected for long periods of time in Chile (1828Chile ( -1832Chile ( , 1834Chile ( -1842)), extensively and in many provinces.Considering the known distribution of P. vulpes, the holotype was probably collected during Gay's expedition to the provinces of Valdivia and Chiloé in October 1834 (Papavero, 1971).
Pelecorhynchus vulpes is a rarely collected species that is poorly represented in collections in Chile and abroad.It probably has a short flight period, and its populations may have been depleted as a result of the significant anthropogenic activity in its area of distribution.The development of land for agriculture and indiscriminate logging with replacement of native species by fast-growing monocultural plantations are the most frequent disturbances that have caused severe fragmentation of the Chilean landscape (Echeverría et al., 2007).The scarcity of this species and others in southern ecosystems also could be explained by phenomena related to climate change that has affected their areas of distribution, decreasing their abundance or causing local extinction (Parmesan, 2006;Robinet & Roques, 2010), changes in their phenology, and increased or decreased synchronization between insects and their food plants in response to climate warming (Forrest, 2016).
The availability of a male specimen collected in 2022 in Región de Los Ríos, Valdivia Province, and photographs of the holotype deposited at the Muséum National d'Histoire Naturelle, Paris, France, allowed us to redescribe the male and to describe the male terminalia, which may provide important diagnostic characteristics for the characterization and differentiation of species.

MATERIAL AND METHODS
The morphological terminology herein follows Sinclair et al. (1994), Carmo & Santos (2011) and Cumming & Wood (2017).Terminalia were macerated in a 10% KOH solution at 50℃ for one hour to dissolve the soft tissue, neutralized with acetic acid, rinsed in distilled water, and then dissected in 80% ethanol.Terminalia were mounted on glass slides in Canadian balsam for examination.Digital photographs were obtained by use of a DS-Fi2 camera mounted on a Nikon SMZ 1500 trinocular stereo-microscope.The depth of the field was enhanced by use of Nikon ACT-2U software to stack multiple images.
Gonzáles, C.R.: Redescription of male of Pelecorhynchus vulpes (Macquart) Pap. Avulsos Zool., 2024;v.64: e202464032 4/5 Remarks: The male terminalia of P. vulpes shows similarities to some Australian species, such as P. albolineatus Hardy, P. fascipennis Mackerras & Fuller P. kippsi Mackerras & Fuller, and P. nigripennis Ricardo, particularly in the shape of the gonostylus (pointed at apex and abruptly expanded at base) and in the development and orientation of the hooks of the aedeagus (Mackerras & Fuller, 1942, Nagatomi, 1984).The genitalia of P. vulpes does not exhibit any morphological similarity with the other species of Chilean distribution, which are currently included in the genus Coenura (González et al., 2023).