Tachinidae

Barahona-Segovia, Rodrigo M., Madriz, Isaí, González, Christian R. & Amorim, Dalton De Souza, 2024, An update on the knowledge and general understanding of the Chilean Diptera diversity, Zootaxa 5518 (1), pp. 1-87 : 48-49

Tachinidae ( Figs. 123–128 )

The family Tachinidae comprises almost 8,600 extant species, grouped into four subfamilies and over 1,500 genera ( O’Hara et al., 2020). Recent molecular studies have provided new proposals for subfamily classification and relationships of Tachinidae ( Stireman et al. 2006, 2019). Cortés & Hichins (1969, 1979), Cortés & Campos (1971, 1974), Cortés (1986), and Cortés & González (1989) made important contributions to the knowledge of the family in Chile. There are 264 species grouped in 122 genera cited for Chile ( O’Hara et al. 2021).

The Diptera fauna from Chile and biogeographical patterns

New branching events along the unfolding of a phylogeny occurs in parallel to changes in the geographic distribution of species. In some cases, the area occupied by a species is separated by vicariance; in other cases, pre-existing barriers disappear, and the species remains in a metapopulation; sometimes, a subpopulation moves across an existing barrier and colonizes unoccupied areas ( Croizat 1958, 1964). This combination of the underlying processes of phylogeny and biogeographical evolution produces local patterns of biotic composition, in which clades of different ages are in sympatry. This means that the composition of any biota corresponds to a mixture of elements from different biogeographical layers ( Amorim et al. 2009).

Lands that belonged to the southern end of Gondwana (e.g., southern Africa, but in most cases New Zealand, southern South America, and Australia) correspond to clear examples of this biotic overlap of layers. It is well documented that many changes in the composition of the flora and fauna of southern Gondwana occurred between the late Jurassic and the Cenozoic, resulting in the present extant biotic diversity in the southern temperate islands and continents (see, e.g., Amorim et al. 2009; Almeida et al. 2012; Lessard et al. 2013). Almost the entire evolution of angiosperms and an important part of the diversification of conifers, hexapods, arachnids, and fungi took place since the Jurassic, gradually changing the biotic composition in this part of the globe.

The biogeographic nature of Chilean biodiversity has attracted the attention and interest of scientists, even before the theory of biological evolution. For example, Joseph D. Hooker (1844 – 1845, 1845 –1847, 1853, 1860) described the plants collected in the Erebus expedition to Tasmania, New Zealand, parts of South America, and other circumAntarctic areas, with comments on the similarities between these floras. Chile is particularly complex in terms of its environmental diversity. There are deserts in the north and temperate rainforests in the south, with a variety of specialized environments in between, of which forests with Araucaria at mountain tops along a restricted latitudinal range is an example. The present composition of the Chilean biota includes animals, plants, and fungi clades that originated at different stages of the Mesozoic and Cenozoic. Among plants and animals, there are elements typical of the early existence of Gondwana, the “Temperate transantarctic track” of Cranston (2005), a late Jurassic layer, elements of a more typical Cretaceous layer, and Cenozoic elements (both fitting Cranston’s “Temperate amphinotic track”). The Cretaceous and Cenozoic layers have biogeographical patterns that connect southern South America with New Zealand / Australia, or only with the latter. This means that connections of southern South America with Africa and New Zealand, not properly explained by secondary occupation, do not belong to the same layer as the cases of disjunction of southern South America with Australia ( Amorim et al. 2009).

Most studies on the biogeographical distribution of elements of Chilean fly fauna (e.g., Croizat 1958, 1964; Monrós 1958; Hennig 1960; Kuschel 1960; Crisci et al. 1991a, b; Craw 1989; Cranston 2005) have concentrated on older (i.e., Gondwanan) biotic connections. Morrone (e.g., 1996 a, b, 2015) and Posadas et al. (1997) clarified the connections of Chilean fauna with other southern South American areas and with elements in more northern areas along the Andes. In Kuschel’s (1960) important early general study on Chilean fauna, connections of elements of the Valdivian Forest with Holarctic and southern Brazilian elements are included, in addition to the usual relationships with other southern cold-temperate areas (including many cases of groups also present in Africa). Hennig (1960, 1964) also carefully considered the connections of Chilean fly fauna with Australia and New Zealand.

A biogeographical layer does not correspond to the age of the disjunction of a clade into its smaller geographically separate components. A set of elements of a given layer in one region connects with corresponding elements in another region to constitute what Croizat (1958, 1964) called a biogeographical trait (see, e.g., Cranston 2005). The age of a biogeographical layer, hence, corresponds to the time of occupation of the ancestral species of a disjunct clade over its entire original range, later split into separate areas in cases of vicariance, or from which a subclade later spread to another area.

Some examples clarify this concept. Along the evolution of the subfamily Bombyliinae , the clade (Adelidini + Nothoschistini ) belongs to an Early Jurassic layer, even though the separation of the Adelidini (mostly in Africa) from its sister-group, the Nothoschistini (mostly in South America) may have occurred in the Late Jurassic ( Li & Yeates 2019). In the evolution of the apoid family Colletidae , the South American subfamily Xeromelissinae is sister to the Australian clade (Callomelittinae + Hylaeinae ) and the Neopasiphaeinae have elements both in Australia and South America ( Almeida et al. 2012). The Colletidae as a whole is supposed to have originated late in the Cretaceous, and the Neopasiphaeinae , is assumed to have originated in the early Eocene, while the disjunction between the Australian and the South American groups occurred only in the Late Eocene due to vicariance along the final separation of the plates at the southern-most end of Gondwana (South America, Antarctica and Australia).

There is still insufficient information to classify the entire Chilean fly fauna into layers. This requires phylogenies for all families down to the genus/species level, fossil data for most clades below the family level, age of clade divergence based on molecular inferences, and geographic sampling across the country. Nevertheless, there are an important number of well-known cases that can be associated with these layers from the Jurassic to Cenozoic. When additional, more detailed reconstructions of the evolution of all fly families become available, it may be possible to split these general layers into even smaller sublayers (e.g., Lower and Upper Jurassic, Lower, Mid and Upper Cretaceous, Palaeocene, Eocene etc.).

We compiled here in ( Table 6), connections of elements of the Chilean fly fauna with elements in Laurasia, Africa, New Zealand and Australia, as well as in other areas in South America (southern Argentina, southern Brazil, and northward along the Andes, in some cases reaching North America). Groups in Chile with connections to tropical areas in South America also correspond to a layer, less explored in the literature, and are mentioned here. Some cases of recently introduced species (the latest layer in the fauna) are mentioned. The main difference between the data below ( Table 6) and previously published compilations (e.g., Kuschel 1960; Hennig 1964) is that: (1) the information now available on phylogeny, fossils, age of divergence based on molecular data, and geology allows us to better understand the origin of dipteran groups and to discriminate to which layers cases of disjunction belong to; (2) cases of connections with other temperate and tropical areas in South America are highlighted. This allowed the consideration of most fly families in the process of understanding the composition of the fauna.

genera and species. Each example provided also associated with a geological layer where the fly family originates.

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Figures

FIGURES 123–128. Tachinidae of Chile: (123) Edwynia robusta (Aldrich) (Tachinidae, photo by Ricardo Varela); (124) Phasia sp. (Tachinidae, photo by Gabriela Germain); (125) Drino insignis (van der Wulp) (Tachinidae, photo by Fernando Tellez); (126) Epicoronimyia mundelli (Blanchard) (Tachinidae, photo by Matías Cortés); (127) Cylindromya porteri (Brèthes) (Tachinidae, photo by Jorge de La Torre Aninat), and (128) cf. Incamyia chilensis Aldrich (Tachinidae, photo by Gabriela Germain).