The Taxonomic Catalog of the Brazilian Fauna (in Portuguese: Catálogo Taxonômico da Fauna do Brasil – CTFB) is a project started in 2015, which now counts with participation of more than 500 zoologists, experts on taxonomy of different animal groups. In December 2016, first results of this project were made available: an on-line checklist of all animal species recorded from Brazilian territory. Since then, species lists have been constantly updated by researchers and more detailed information has been provided for each species such as a complete synonymic list, references, distributional data by region, state, biome, and hydrographic basin. All this information can be freely accessed on: http://fauna.jbrj.gov.br/fauna/listaBrasil. Brazil is a megadiverse country and for most of animal groups, specially arthropods, we certainly know only a fraction of the species occurring in the country, so building such database is not trivial.

The Trichoptera team working from the beginning of the project consists of seven Brazilian taxonomists, the authors in this paper. Since checklists and catalogs including caddisfly fauna from Brazil were already published elsewhere (e.g. Neotropical Catalogs: Flint et al. 1999 and Holzenthal and Calor 2017; checklists: Blahnik et al. 2004, Paprocki and França 2014), we used these as initial data sources, recovering detailed information from original papers addressing each species. As a result, we provided a constantly up to date taxonomic list for Brazilian caddisfly fauna, also including for each species hierarchy classification, synonymic list, distribution for Brazilian biomes (Fig. 1), hydrographic regions (Fig. 2), and states (Fig. 3), and bibliographic references. Additional data, for example type locality and depository, voucher information, links to other databases are already being inserted in the CTFB, but this will be made public only in future versions.

The database is available for public search in its updated on-line version (CTFB website), providing the following information: (1) taxonomic status of the name; (2) taxonomic hierarchy; (3) taxa included; (4) synonymic list; (5) if native from Brazil; (6) if endemic to Brazil; (7) geographic distribution in Brazil; (8) references recording the taxon in Brazil. The data used here (until August 2019) is provided in Suppl. S1 and an updated version of this spreadsheet is available upon request to corresponding author. We believe all this information, such as previous checklists and catalogs, will make easier to investigate the taxonomic diversity of caddisflies in Brazil and we also hope this will stimulate more research on this group in our country. The database is also relevant because it shows us through precise numbers, priority areas and taxonomic groups to focus new collecting effort and research. Here, we used the database to estimate the total number of species to occur in Brazil and the similarity among biomes and hydrographic basins.

Caddisfly taxonomy in Brazil started with Josef A. Maximilian Perty, a German naturalist who published a series of works called “Insecta Brasiliensia” (1830–1834), including the first Brazilian caddisfly species in 1833 (also the first from Neotropics): Phryganea maculata, currently Macrostemum brasiliense (Fischer, 1970) (Fig. 4). Later in 19^th century others described about a dozen of Brazilian caddisflies species (e.g. Pictet 1836, Burmeister 1839, Brauer 1865, McLachlan 1871). Early in 20^th century, Ulmer (1913) provided the first checklist of Neotropical caddisflies, listing 162 species, 60 recorded from Brazil. Following that, several authors (e.g., Banks, Müller, Navás, Ulmer) described and recorded many genera and species for the country (e.g. Figs 4–7), notably Johann Friederich Theodor Müller, a German naturalist who lived most of his life in Santa Catarina, Southern Brazil. Fritz Müller (as he is widely referred) worked as a travelling naturalist for the National Museum, in the city of Rio de Janeiro, Rio de Janeiro State, Brazil, although he never lived in this city. During his life in Santa Catarina, Fritz Müller had continuous correspondence with Charles Darwin and described many invertebrate species in about 250 publications, including 21 Brazilian caddisflies. Sadly, specimens studied by Fritz Müller, mainly larval cases, were lost in the devasting fire that destroyed most of the entomological collection in the National Museum in September 2018.

Figures 4–7. 

Adults of Brazilian caddisflies: (4) Macrostemum brasiliense (Fisher, 1970), the first caddisfly species described from Brazil, originally as Phryganea maculata Perty, 1833 (photo by FF Salles), Espirito Santo state; (5) Centromacronema auripenne (Rambur, 1842), a problematic taxon with several synonyms and in need of a taxonomic revision, Rio de Janeiro state; (6) Nectopsyche sp., an unidentified species of this diverse and poorly studied genus, Rio de Janeiro; (7) Marilia sp., an unidentified species of another genus in need of taxonomic revision, Amazonas.

At second half of 20^th century, the knowledge of Brazilian caddisfly fauna increased considerable due to the work of Dr Oliver S. Flint Jr (National Museum of Natural History, Smithsonian Institution, USA). Dr Flint Jr produced more than a hundred works on Neotropical fauna of Trichoptera, including many taxonomic and revisional publications of entire families and genera, and described more than 200 species from Brazil. Another important group of trichopterologists responsible for important contributions to Brazilian caddisfly taxonomy is that headed by Dr Ralph Holzenthal and Dr Roger Blahnik. Holzenthal, Blahnik, and their collaborators have described more than 150 species for the country, in addition to performing dozens of revisionary works.

After Fritz Müller (who was German-Brazilian), the first Brazilian to describe a caddisfly species was Dr Angelo Machado, despite being a dragonfly specialist. He described a snail-case caddisfly for the state of Minas Gerais – Helicopsyche planorboides Machado, 1957. It was only in 2002, almost 50 years later that another Brazilian described Brazilian caddisfly species, Dr Gisele Almeida and Dr Oliver S. Flint Jr with five species of Smicridea McLachlan, 1871 (Hydropsychidae) from the Southeast Brazil (Almeida and Flint 2002). Today, the current number of caddisfly taxonomists working and residing in Brazil has increased, although we are still far from an adequate number.

The first caddisfly described from Brazil dates from 1833, 75 years after publication of the Tenth Edition of Systema Naturae (Linnaeus 1758) and the beginning of modern zoology taxonomy. Due to politic and historic issues, in the 19^th century, naturalists from Europe were responsible for almost all descriptions of caddisflies from Brazil. Peaks of species descriptions in the second half of the 20^th century, as shown in Fig. 9, correspond to massive works of Dr Oliver S. Flint Jr in South America, with special attention to the Amazon Region (e.g. Flint 1971, 1978, 1998). By the end of the 20^th century and beginning of the 21^th century, Dr Ralph Holzenthal, Dr Blahnik, and collaborators were responsible for most species descriptions. Except for F. Müller, Dr Angelo Machado was the first Brazilian to describe a caddisfly, in 1957. But it was only after the year 2000 that publications from researchers working in the country started to proliferate, and now we can notice a strong upward trend in accumulation curve of species described by Brazilians (Fig. 11). It is noteworthy that Dr Jorge Nessimian contributed naming 108 species so far, and still working and advising new students on caddisfly taxonomy.

Trichoptera are one of the most diverse group among aquatic insects. Despite this, taxonomic diversity in the World remains poorly studied (Dijkstra et al. 2014). In Brazil, with more intense participation of Brazilians in studying the taxonomy of caddisfly, our knowledge about the fauna increased rapidly in recent years, going from 378 species listed in the checklist provided by Paprocki et al. (2004) to 796 today. This means that more than half of the species known to Brazil were described in the last 14 years. In this way, grants and fellowships directed to researchers working on taxonomic projects were very important to promote caddisfly taxonomy in Brazil.

In current numbers, Brazilian caddisfly fauna represents less than 5% of the world diversity of Trichoptera species (Table 1). Among aquatic insect orders, this percentage is higher only than Plecoptera (4.3%). Based on caddisfly distribution throughout Brazilian states, JACK2 estimated 1,588 species to the country, almost twice the current number of known species. Assuming this estimation is close to reality, this value would correspond to about 10% of the world caddisfly fauna. Compared with well-studied groups, this is still a low number, for example, Odonata are represented in Brazil by 867 species, almost 14% of the global odonatan fauna. An even higher number for caddisfly diversity in Brazil was predicted by Paprocki (2012), around 3,000 species, but this was not based on statistical analyses. Accumulation curve of described species shows a strong upwards trend in the last years (Fig. 10), which indicates that there is much more species to be described to reach the real caddisfly diversity in Brazil. Ríos-Touma et al. (2017) listed 310 caddisfly species to Ecuador and estimated 578 with CHAO 2 estimator. Since Brazilian territory occupies most of South America and encompasses areas of high diversity and concentration of endemism such as Amazon Forest, Atlantic Forest, and Cerrado, it will not be surprising if the actual number exceeds 2,000 species.

Hydroptilidae are the most diverse family in Brazil with 158 species and many more species remain to be described, the same for the rest of the world’s fauna. In Brazil, 22 genera are recorded and only a few of these were focus of recent taxonomic papers (e.g. Wasmund and Holzenthal 2007, Thomson and Holzenthal 2015, Santos et al. 2016a, b, Souza and Santos 2017, Thomson 2019) (Suppl. S6). More than a third of the species in the family is in Neotropical Region (Morse et al. 2019) and they are usually neglected by caddisfly workers due to their small sizes (in general less than 5.0 mm), resulting in many unsorted or unidentified specimens in collections. For this reason, it is common to find high number of new species when examining caddisfly samples in collections or when collecting new material in Brazil. Even historically well studied areas in Brazil, as the Southern region, usually reveal a high number of hydroptilid new species. In this family, genera with many species in collections waiting to be named are Alisotrichia Flint, 1964, Flintiella Angrisano, 1995, Hydroptila Dalman, 1819, Neotrichia Morton, 1905, and Oxyethira Eaton, 1873.

The second most diverse family in the country is Hydropsychidae with 138 species (in 9 genera), over a third of them in the speciose genus Smicridea (55). Despite the apparently high number, many more undescribed species of Smicridea from Brazil are sitting in collections, but the genus needs a careful taxonomic revision to clarify the identity and boundaries of its taxonomic units. Another complex group of hydropsychid genera are Centromacronema Ulmer, 1905 and Macronema Pictet, 1836. Both genera are endemic to the Neotropical Region and their adults usually have brightly colored wings (Holzenthal and Calor 2017). Since these colored adults are also large and mostly day active, many Centromacronema and Macronema species were already described in the 19^th century or the beginning of the 20^th century (Holzenthal and Calor 2017). Although some species have been described recently, identity of several older names are unclear (Holzenthal and Calor 2017). Among the Neotropical hydropsychids, certainly these two genera are the ones that most need taxonomic revisions (Suppl. S6), with a careful re-examination of each type specimen available. Leptonema Guérin-Méneville, 1843 and Macrostemum Kolenati, 1859 are other two diverse Hydropsychidae genera in Brazil, respectively with 32 and 17 species recorded. However, for these two world distributed genera, taxonomic revisions are available. For Leptonema, a revision for the whole genus was published (Flint et al. 1987) and for Macrostemum, a review including all Neotropical species (França et al. 2013).

Leptocerids are the second most speciose caddisfly family in the world with more than 2,000 known species (Morse et al. 2019). In Brazil, the number of described species of Leptoceridae (88) is smaller than Polycentropodidae (105) and Philopotamidae (93). However, the diversity of leptocerids is poorly explored in Brazil, and in Neotropics as a whole, mostly because two large genera, Nectopsyche Müller, 1879 and Oecetis McLachlan, 1877, were not recently revised and likely include much more species than current numbers. On the other hand, Polycentropodidae and Philopotamidae genera were focus of recent taxonomic works (see Suppl. S6). For example, the recently described genus Alterosa Blahnik, 2005 was established in 2005 to include two previously known species and several new ones. Now it includes 39, all of them restricted to mountainous areas of Atlantic Forest in Brazil (Blahnik 2005, Dumas and Nessimian 2013, Dumas et al. 2013). Although, even for those revised genera undescribed species are still being discovered and it is likely that leptocerids, along with hydroptilids and hydropsychids, correspond to the three more speciose families in Brazil.

Information about distribution of living organisms are usually biased due to unequal pattern of collecting effort (the “Wallacean shortfall” – Hortal et al. 2015) and caddisflies are not an exception. Despite the increase of published taxonomic papers in recent years on Brazilian caddisfly fauna, the distribution of caddisflies in Brazil still reflects areas of higher concentration of research centers, in the Southeastern and Northern regions. As a result, more than half of the recorded species from Brazil occurs in the Atlantic Forest (495 of total 796 species) and the Amazon Forest is the second biome in number of species (255).

The Neotropical Region shows a high number of endemic caddisfly taxa and, in terms of number of endemic genera, it is surpassed only by the Australasian Region (de Moor and Ivanov 2008). The high number of endemic caddisfly taxa to Brazil is not surprising. Despite the uneven collecting effort, endemism of caddisfly fauna in Atlantic Forest is remarkably high with about 60% (298) of species recorded being endemic, a proportion much higher compared with vertebrates or plants (about 40%, Myers et al. 2000). As typical for tropical mountains, which quite often house many endemic species (Steinbauer et al. 2016), Atlantic Forest mountains in Southeastern Brazil show high numbers of caddisfly species richness, with several endemic taxa (Dumas and Nessimian 2012, Henriques-Oliveira et al. 2018). Among these endemic taxa we can highlight Antarctoecia brasiliensis Huamantinco & Nessimian, 2003 and Neoatriplectides desiderata Dumas & Nessimian, 2008, respectively the only Limnephilidae and Atriplectididae species to occur in Brazil, both families typically represented in South America by Andean species.

Among the top five most diverse families, philopotamids have relatively higher proportion of endemic species in Atlantic Forest, with 83% of the recorded species being endemic to this biome. As mentioned above, Philopotamidae are represented in the Atlantic Forest by Chimarra Stephens, 1829 and by the endemic genus Alterosa. Since the Atlantic Forest is one of the most threatened biomes in the World (Myers et al. 2000, Mittermeier et al. 2004), and currently only about 12% of its natural area remains (Ribeiro et al. 2011), knowing better the distribution of these endemic taxa are extremely important to the conservation of our biodiversity.

Since there has been an unbalanced collecting effort, with most of taxonomic studies on Brazilian caddisfly being limited to Amazon and Atlantic forests, comparing composition among biomes or hydrogeographic regions is not easy. Although most groups of clustering analysis had weak support, dissimilarity among hydrographic regions indicate two groups, one with northwestern regions (Amazon, Tocantins-Araguaia, Paraguay, Western Northeast Atlantic, Parnaíba, and Eastern Northeast Atlantic) and another with southeastern regions (São Francisco, East Atlantic, Southeast Atlantic, South Atlantic, Uruguay, and Paraná) (Fig. 12). These groups are interesting in a biogeographic point of view because they could represent a disjunction between an Amazonian and an Atlantic Forest faunas. The Amazon and the Atlantic forests are separated by a dry corridor, the South American dry diagonal, comprising the Chaco, Cerrado, and Caatinga biomes (Ab’Saber 1977). Several studies have indicated past connections between these two Neotropical forests (e.g. Costa 2003, Sobral-Souza et al. 2015). However, formation of this drier area separating Amazonia from Atlantic Forest over the evolutionary time could be a relevant factor to explain current distribution of caddisfly species throughout the Brazilian biogeographic component.

The Brazilian Cerrado occupies a larger area than the Atlantic Forest, about half of the Brazilian Amazon area (Suppl. S2), and it is also a world biodiversity hotspot (Myers et al. 2000). On the other hand, the Caatinga is slightly smaller than the Atlantic Forest and usually associated with low number of species. Caddisfly diversity in the Caatinga and Cerrado was only poorly studied, but recent works on these dry biomes have revealed high numbers (Costa et al. 2014, Quinteiro et al. 2014, Takiya et al. 2016, Henriques-Oliveira et al. 2018). Surveys on caddisflies from the Caatinga and Cerrado are crucial and increasingly needed to understand the effect of the dry corridor as a potential barrier to aquatic insects during the formation of South American forested biomes. Based on this, biogeographic and phylogeographic studies using refined data of caddisfly taxa have potential to reveal insights about the complex events related to the formation of Neotropical biomes.