A checklist

William Galvis

95 families, 1385 genera and 13708 species

Abstract. The Neotropical region is currently considered one of the richest regions in biodiversity on the planet. In turn, it is one of the eight major biogeographic regions of the world, with the lowlands of central and southern Mexico being considered the northern continental limit (this is the same southern limit of the Nearctic region, whose fauna and flora apparently is more related to European and Asian regions; sometimes Neartics is included as part of the Holartics), and the Bahamas the northern oceanic limit. The southermost limit of Neotropical realm is placed at the northern region of the Andean-Patagonian zone, found at northern Chile and central-northern Argentina. The Andean-Patagonian zone includes the so-called Subantarctic Forests, and corresponds to the Antarctic or Andean ecozone (more closely linked to New Zealand, Australia and Antarctica). 

Anyhow, all Neotropical countries and dependent or independent political units are included in the present list of spider species, from Mexico and Guatemala to the north, the rest of Central America, the region of the Tropical Andean Countries - ArachnoTrAC (Colombia, Venezuela, Ecuador, Peru, and Bolivia), the Guyanas, Brazil, Paraguay, Uruguay, and Chile and Argentina to the south, for its continental portion. For the Pacific Ocean it includes the Galapagos Archipelago, and for the Caribbean Sea and Atlantic Ocean both the Bahamas and the Antilles.

Taken from Morrone et al. (2022) >

In this sense, for the first category the search was restricted to 21 countries that are part of the continental Neotropics, from north to south: 

• Mexico, Guatemala, Belize, Honduras, El Salvador, Nicaragua, Costa Rica, Panama, Colombia, Venezuela, Guyana, French Guiana, Suriname, Brazil, Ecuador, Peru, Bolivia, Paraguay, Uruguay, Chile and Argentina.

For the second category, the search was restricted to 25 political units that are part of the insular  Neotropics, from north to south: 

• Bahamas, Cuba, Turks & Caicos Islands, Cayman Islands, Jamaica, Haiti, Dominican Republic, Puerto Rico, British Virgin Islands, US Virgin Islands, Anguilla, St Kitts & Nevis (including Saba and Sint Eustatius), Antigua & Barbuda, Montserrat, Guadeloupe, Dominica, Martinique, St Lucia, Barbados, St Vincent & The Grenadines, Grenada, Trinidad & Tobago, ABC Islands (Aruba, Bonaire & Curaçao), Saint Martin Island, and Saint Barthélemy; for Atlantic Ocean and Caribbean.

• Galápagos Islands, for Pacific Ocean.

For the third category the search was restricted to regional names and historical names, some of which are still in use, as follows:

• The Americas, South America, Andes, Central America, Caribbean, Lesser Antiles, Greater Antilles, Hispaniola, Netherland Antilles, Winward Islands (southern and easternmost arc of islands of Lesser Antilles).

After that, resulted species list was compiled and organized alphabetically, in a spreadsheet, family per family, genus by genus, and species by species to be revised manually species by species. Resulted family lists were organized in Mygalomorphae and Araneomorphae. 

Results. The assessment revealed that the Neotropical spider fauna comprises 95 families, 1370 genera, and 13520 species. These results represents 72% of the families, 32% of the genera and 26% of the species of spiders of the world! In addition, it was found 98.9% of the species are endemics to America. 

Finally, these results also shows that 95 species have been introduced into Neotropics from other regions (Neartics, Paleartics, Paleotropics, Pacific Islands, South East Asia, etc); 49 species have been exported from Neotropics to other regions; and some other few species has been introduced from some Neotropical regions to other Neotropical regions. Those lists are also included to the end of the checklist.

Checklist. The complete checklist of spiders occurring in Neotropical countries is given, family per family, ordered by genera and species. Checklist also included the original author of the name of the species, together with its known distribution. Those species confirmed, record by record, as not Neotropical, they were included in Neotropical Spiders - A excluded species list.

Clarification. The inclusion of Chile, Argentina and Mexico is justified by the fact that these countries have a part of their territories included on Neotropical region. Most of their spider species are therefore included until their biogeographic and Neotropical affinity can be verified species by species. For example, the family Atypidae (with its only species of the genus Sphodros, S. paisano Gertsch & Platnick) described from North America was recently reported from Ciudad Madero, Tamaulipas, being this the southernmost record of the family for America, entering into Neotropics, at Veracruzan province. Or, on the other hand, the family Austrochilidae, in southern South America, with two genera (Austrochilus and Thaida) with some of their species limiting at their distributions, or included, in the Neotropical region, at South American transition zone. 

On the other side, Chilenodes australis Platnick & Forster, 1987 from Chile, the only one species of the family Malkaridae to be known from America is not included: this species have an Andean zone biogeographical relationship, it is only known from southern Chile. The same pattern is found with the family Physoglenidae and its five described species in the genera Chileotaxus and Physoglenes from central-south Chile. Or, Myrmecicultor chihuahuensis Ramírez, Grismado & Ubick, 2019, the only one species of Myrmecicultoridae, known from southern USA and northern Mexico, which is also not included instead of its near distribution close to the Transmexican Volcanic Belt province, in the Mexican transition zone of the Neotropics.

Excluded Species. This checklist includes those species whose distributions have a Neartic (highlands of northern and central Mexico, and further north) or Andean (northern ot south Chile, and central-southern Argentina, and further south) biogeographic relationships. Checklist can be revised here.

Anyway, approximately >90% of the species found here in the Neotropical spider checklist will actually be associated with the Neotropical region. 

MYGALOMORPHAE

21 families, 177 genera and 1346 species

ARANEOMORPHAE

74 families, 1198 genera and 12227 species