﻿A revised, annotated checklist of Mexican non-biting midges (Diptera, Chironomidae)

﻿Abstract An updated checklist of Mexican non-biting midges (Chironomidae) is presented. A total of 110 species of Chironomidae are known for Mexico: 52 species in 25 genera belong to the subfamily Chironominae, 30 species in 13 genera to Orthocladiinae, 21 species in nine genera to Tanypodinae, five species in two genera to Telmatogetoninae, and two species in one genus to Diamesinae. In addition, 41 genera without identified species are listed. The highest number of species (29) is recorded from the state of Campeche, while 19 species have been found in Veracruz and 15 in Nuevo León. Few or no records exist for states in Central and Northern Mexico, or those on the Pacific coast. The type localities for 34 species are in Mexico; of these, 27 species (25% of the total number of species recorded in the country) are endemic. Twenty-nine species recorded in Mexico have a Neotropical distribution, 15 a Nearctic distribution, and 39 species are distributed in both the Neotropical and Nearctic regions or more widely. It has been suggested that as many as 1000 species might occur in Mexico; so only a little more than 10% of the expected diversity has so far been recorded.


Introduction
Mexico is a megadiverse country (Mittermeier et al. 2011;Mendoza-Ponce et al. 2020).Located in the Nearctic-Neotropical transition area, the north to south orientation of numerous warm, low altitude corridors, and the abundance of mountain chains with colder conditions have allowed biota to disperse during past climate change events (Halffter 1987).This high biodiversity results primarily from an accumulation of taxa from other areas and constant changes in the landscape (Priego Santander and Esteve Selma 2017) rather than local diversification (Sundaram et al. 2019;Harvey et al. 2020).However, several of the most species rich and ecologically relevant insect groups are not included in these studies.Chironomidae have the widest distribution of all free-living groups of holometabolous insects and are likely the most taxonomically and ecologically diverse family of aquatic insects (Cranston 1995;Dijkstra et al. 2014).Reiss (1982) estimated that between 1500-2000 chironomid species might occur in tropical Mexico and Central America, and Andersen et al. (2000) suggested that as many as 1000 species can be expected to occur in Mexico.Spies et al. (2009) compiled an annotated list of the Mexican and Central American genera including a key to the genera known from the region at that time.However, the latest inventory of the Mexican chironomids only included 61 species plus an additional 25 genera without identified species (Andersen et al. 2000).
During the last two decades, several new species have been described based on material from Mexico (Kyerematen et al. 2000;Kyerematen and Andersen 2002;Wang et al. 2006;Vinogradova 2008;Andersen et al. 2010Andersen et al. , 2016;;Wiedenbrug et al. 2012;Pinho et al. 2013;Acosta et al. 2017;Pinho and Andersen 2021;Andersen 2023).Several species and genera have also been recorded for the first time from Mexico, especially in connection with surveys of particular habitats like the aquatic fauna in spring-fed tropical canyons in the southern Sonora desert (Bogan et al. 2014), or subfossil Chironomidae in surface sediments of the sinkholes of the Yucatan Peninsula (Hamerlík et al. 2018).Several of these studies are based mainly on larvae and the materials are generally not identified beyond genus level.
The Nearctic-Neotropic transition should lead to the existence of chironomid species with different biogeographic affinities.The Nearctic fauna is comparatively well known (Oliver et al. 1990;Oliver and Dillon 1994) and most chironomids in Mexico with this biogeographic affinity can be identified to genus level using the keys to the larvae, pupa and adults of the Holarctic Region (Wiederholm 1986(Wiederholm , 1989;;Andersen et al. 2013a).The Neotropical chironomids from Mexico are much less studied and more difficult to identify based on available literature.
An updated checklist of Mexican Chironomidae species is presented.The list provides an updated baseline and will facilitate the study of the chironomid fauna in the Nearctic-Neotropical biogeographical transition zone in Mexico.The checklist is based on Andersen et al. (2000), and new records and species published during the last two decades are added.Some ecological information now available for the genera recorded from Mexico are also included.

Methods
The checklist is based on Andersen et al. (2000); references already given in that list are not repeated here.The checklist includes published records only.Records were compiled from peer reviewed scientific articles, books, and book chapters and, to a lesser extent, unpublished project reports.Specimens of Mexican chironomids are housed in several collections (Contreras-Ramos 2021; Huerta Jiménez 2021; Admin 2022; Bentley and Thomas 2022; European Bioinformatics Institute 2022); and these records can be accessed using "Name search" in GBIF (2023).
Following Ashe and O´Connor (2009) eight major zoogeographical regions are recognized: Antarctic (AN), Neotropical (NT), Nearctic (NE), Palaearctic (PA), Afrotropical (AF), Oriental (OR), Australasian (AU), and Oceanian (OC).Administratively, Mexico is divided in 32 states.Of these the 18 northernmost states are generally regarded as belonging to the Nearctic region, while the remaining 13 southern most states as belonging to the Neotropical region (Ashe and O´Connor 2009).However, the biogeographical zones are not clearly defined and depend to some degree on the group of organisms studied.There are also clearly transition zones between the two regions.Given this, taxa present in Mexico and in Central or South America are considered to be Neotropical, while taxa present in Mexico and in the USA and/or Canada are considered to be Nearctic.The exception is taxa from southern Florida, USA, which is considered to be Neotropical.However, many species are found both in South-and North America or have a wider distribution.
The checklist is arranged alphabetically.Species group names follow the genus and subfamily names.A short outline with information on the number of species, distribution, and larvae habitats is given for each genus.For literature records given as "Cricotopus cf.sylvestris" or "Cricotopus sylvestris group" we assume they are correctly identified to genus level.Following Ashe and O'Connor (2009), two Tanypodinae species originally described as Macropelopia roblesi Vargas, 1946 andPentaneura marmorata Johannsen, 1938 are listed as "Generically unplaced valid Macropelopiini" and "Generically unplaced valid Tanypodinae", respectively.
The valid species name is followed by the original combination in parenthesis, with type country (for USA, country and state) in square brackets.When the type locality is situated in Mexico, more specific information is given for the type locality.Synonyms are given if descriptions are based on Mexican material.Mexican records are then given followed by the state(s) from where the species is recorded in square brackets.Finally, the total distribution for a species is given as zoogeographical region(s), followed by the countries from where the species has been recorded.However, this list of countries might not be complete, and for widespread species it is only given as "widespread".
In the checklist, recorded genera lacking identified species are included.Mexican records are listed as e.g.: Cryptochironomus sp., followed by the state(s) from where the genus is recorded in square brackets.Vinogradova and Riss (2007) provided numerous records from the Yucatan Peninsula, but without giving any details on the localities.As Yucatan Peninsula includes partly or totally the territory of three Mexican states; these records are listed as ["Yucatan Peninsula"].

Genus Chironomus Meigen, 1803
One of the most species-rich and common chironomid genera, with ~ 300 described species from all zoogeographical regions except Antarctica.The larvae graze on detritus or are filter-feeders, predominantly in soft sediments of standing water, rarely in flowing water (Epler et al. 2013).

Genus Cladopelma Kieffer, 1921
A genus of ~ 20 described species that occur in all zoogeographical regions except Antarctica and Oceania.The larvae live in streams and larger rivers, lakes, and ponds as well as brackish water and hot springs (Epler et al. 2013).

Genus Cladotanytarsus Kieffer, 1921
A genus of ~ 80 described species that occur in all zoogeographical regions except Antarctica and Oceania.No named species are recorded from South America, but larval morphotypes have been recorded from Brazil (Roque et al. 2004).Larvae construct sessile cases of fine detritus and have been found in streams and larger rivers, lakes, and ponds, as well as in brackish water and hot springs (Epler et al. 2013).

Genus Cryptochironomus Kieffer, 1918
A genus of ~ 60 named species that occur in all zoogeographical regions, except Antarctica.Four species are described from South America (da Silva et al. 2010).Larvae occur on various substrates in lakes, small streams, and larger rivers (Epler et al. 2013).

Genus Dicrotendipes Kieffer, 1913
A genus of ~ 85 described species that occur in all zoogeographic regions except Antarctica.The genus was revised by Epler (1988).The larvae inhabit the littoral sediments of standing waters and may be common in lentic habitats (Epler et al. 2013).

Genus Endochironomus Kieffer, 1918
A genus of ~ 20 named species distributed in the Nearctic, Palaearctic, Afrotropical, and Oriental regions.The larvae occur in "Aufwuchs" on living and dead substrata in almost all types of still water; they mine leaves and stems of macrophytes preferentially in small, eutrophic standing waters (Epler et al. 2013).

Genus Endotribelos Grodhaus, 1987
A genus of 14 described species, all occurring in the Neotropical and Nearctic regions except one species from China.The Brazilian species were treated by Trivinho-Strixino and Pepinelli (2015).The larvae are associated with aquatic macrophytes, decaying leaves, wood, and fallen fruits in streams (Epler et al. 2013).

Genus Fissimentum Cranston & Nolte, 1996
A genus with four named species endemic to South America; but larval morphotypes have also been recorded from the Nearctic, Oriental, and Australasian regions (Epler et al. 2013).Larvae are found in fine sediments of lentic and lotic habitats and can tolerate desiccation (Cranston and Nolte 1996).

Genus Goeldichironomus Fittkau, 1965
A genus of 15 named species mainly distributed in the Neotropical region (tropical and subtropical Central and South America), but several species reach their northern limits in southeastern USA (Donato and Andersen 2022).The larvae of Goeldichironomus are mostly found in sediments, on plants or in floating mats of vegetation in lentic habitats, in fresh to brackish water, and in oligotrophic to hypereutrophic conditions (Epler et al. 2013).

Genus Harnischia Kieffer, 1921
A genus of ~ 20 described species that occur in all zoogeographic regions except the Antarctic, Neotropical, and Oceanian regions.However, unnamed larvae have been recorded from Brazil (Roque et al. 2004).Larvae occur in soft sediments of generally clean lakes and larger rivers (Epler et al. 2013).

Genus Hyporhygma Reiss, 1982
A genus with a single named species, H. quadripunctatum (Malloch, 1915), distributed in eastern North America, from Newfoundland to Florida.The larvae mine leaves and stems of Nuphar and Nymphaea species (Epler et al. 2013).
A genus with at least five species in the Holarctic region.Species previously considered to belong to Nilodorum are widespread in the Afrotropical, Oriental, and Australasian regions.The larvae inhabit sediments of small to medium sized waterbodies (Epler et al. 2013).

Genus Lauterborniella Thienemann & Bause, 1913
A genus with a single named species, L. agrayloides (Kieffer, 1911) distributed in the Neotropical, Nearctic, and Palaearctic regions.Other species referred to as Lauterborniella in the literature belong either to Zavreliella Kieffer, 1920 or to Kribiodorum Kieffer, 1921, or their generic affinities are unclear (Epler et al. 2013).
Larvae are mobile amongst submerged vegetation in small bodies of standing water (Epler et al. 2013).In Brazilian streams they have also been found in accumulations of litter attached to stones (Sanseverino and Nessimian 2001).

Genus Microchironomus Kieffer, 1918
A genus of approximately ten species distributed in the Nearctic, Palaearctic, Afrotropical, and Oriental regions (Yan and Wang 2006).The larvae occur in lakes, rivers, and ditches, including brackish water (Epler et al. 2013).

Genus Micropsectra Kieffer, 1909
Based on morphological and molecular data, Krenopsectra Reiss, 1969 andParapsectra Reiss, 1969 were recently considered to be junior synonyms of Micropsectra (Ekrem et al. 2010).The three genera have a Holarctic distribution with ~ 100 valid species.The larvae have been recorded from a wide range of habitats, including hygropetric situations, thermal springs, moorland pools, and temporary pools.They are often found in muddy deposits in slow flowing stretches of streams and small rivers and in mesotrophic and oligotrophic lakes (Epler et al. 2013).

Genus Microtendipes Kieffer, 1915
A genus of ~ 55 named species that occur in all zoogeographic regions, except Antarctica; Neotropical records are based only on larvae not identified to species level (Roque et al. 2004).Larvae are found in littoral and sublittoral sediments of lakes, and in sediments and submerged mosses in running water (Epler et al. 2013).

Genus Parachironomus Lenz, 1921
The genus has a worldwide distribution with at least 30 species in the Holarctic region and 20 species in the Neotropical region (Trivinho-Strixino et al. 2010;Epler et al. 2013).The adults of the Neotropical species were revised by Spies et al. (1994).Larvae are found in lentic and lotic water bodies under a wide range of conditions, including leaf miners in submerged macrophytes; they also live in association with Bryozoa or are ectoparasites on other invertebrates (Epler et al. 2013).Remarks.According to Spies (2000: 133) the record from Puebla is based on Alcocer et al. (1993) and must be considered as uncertain as it appears to be based on immature specimens only.

Genus Paracladopelma Harnisch, 1923
The genus has a predominantly Holarctic distribution, with at least 20 known species; many species are also recorded from the Oriental region (Epler et al. 2013;Yan et al. 2008).The Holartic species were reviewed by Jackson (1977).
Larvae inhabit sandy substrata in lakes, streams, and small rivers and the soft profundal sediments of deep lakes (Epler et al. 2013).

Genus Paratendipes Kieffer, 1911
A genus of nearly 40 named species that occur in the Afrotropical and Oriental regions and in the Holarctic realm (Qi et al. 2009).For South America there are only records of unnamed species (Roque et al. 2004;Trivinho-Strixino 2011).Larvae are found in lakes, ponds, small water bodies, bogs, and hot springs and in streams and rivers in soft sediments and sandy bottoms (Epler et al. 2013).

Genus Phaenopsectra Kieffer, 1921
A genus of more than ten named species that occur in all zoogeographical regions except the Antarctic, Oriental, and Australasian regions.The larvae mainly occur in sandy and muddy sediments of small standing and flowing waters, but also on submerged water plants and hard substrata (Epler et al. 2013).The largest genus of Chironomidae, with > 500 described species that occur in all zoogeographical regions except Antarctica.Based on imaginal characters, eight subgenera were recognized by Saether et al. (2010), namely Tripedilum Kieffer, 1921;Polypedilum s. str.;Pentapedilum Kieffer, 1913;Tripodura Townes, 1945;Uresipedilum Oyewo & Saether, 1998;Cerobregma Saether & Sundal, 1999;Kribionympha Kieffer, 1921;and Probolum Andersen & Saether, 2010.However, the delimitation of the subgenera within Polypedilum was questioned by Yamamoto and Yamamoto (2015) and Cranston et al. (2016b).The position of Asheum is unclear but is usually treated as a subgenus within Polypedilum (see Pinho and Silva 2020).Larvae of Polypedilum occur in virtually all still and flowing waters, except in the Arctic and at high elevation.They are mostly found in sediments, mining water plants or specializing in plant-held waters (phytotelmata) (Epler et al. 2013).

Genus Rheotanytarsus Thienemann & Bause, 1913
A genus with ~ 100 species distributed in all zoogeographic regions except Antarctica.The Central American and Mexican species were reviewed by Kyerematen and Andersen (2002); the Rheotanytarsus pellucidus group was revised by Kyerematen et al. (2000).Larvae are rheobiontic, occurring in streams, large rivers, and the littoral of lakes where wave action simulates the action of flowing water (Epler et al. 2013).

Genus Saetheria Jackson, 1977
A genus of seven named species that occur in the Neotropical, Nearctic, and Palearctic regions (Orel 2014).Only unnamed larvae have so far been recorded from South America (Roque et al. 2004).Larvae inhabit sandy substrata of lakes and streams (Epler et al. 2013).

Genus Skutzia Reiss, 1985
A genus of six species that occur in the Neotropical, Nearctic, and Oriental regions.
The genus was revised by Pinho et al. (2009a).The larvae are unknown.However, they can be expected to construct transportable cases of sand grains, small wood or plant remains, as seen in the larvae of other species in the subtribe Zavreliina.

Genus Stempellina Thienemann & Bause, 1913
A genus of at least 20 species that occur in all zoogeographic regions except Antarctica.The larvae construct long, curved, tapered, transportable cases of fine sand and silt.They are eurytopic, occurring in springs, streams, larger rivers, lakes, brackish water, moorland pools, and in thermal springs (Epler et al. 2013).

Genus Stempellinella Brundin, 1947
A genus of ~ 20 described species that occur in all zoogeographical regions except Antarctica.The larvae construct straight, transportable cases of fine sand and silt, often speckled with detritus; they occur in unpolluted springs and small streams as well as in lakes (Epler et al. 2013).

Genus Stenochironomus Kieffer, 1919
A genus of > 100 described species that occur in all zoogeographic regions except Antarctica.The genus was revised by Borkent (1984).South American species were treated by Dantas et al. (2016).Larvae are obligate miners in living or dead vegetation including woody parts of plants, in both lentic and lotic situations (Epler et al. 2013).A species-rich genus with > 350 described species that occur in all zoogeographic regions except Antarctica.A molecular phylogeny of the genus was presented by Lin et al. (2018), placing Caladomyia as a junior synonym of Tanytarsus.The larvae are found in all types of freshwaters, with some marine, and at least one terrestrial species.The freshwater species usually construct long, soft tubes that are fixed to the bottom substrate (Epler et al. 2013).

Genus Tribelos Townes, 1945
A genus with less than 10 named species distributed mainly in the Nearctic and Palaearctic regions.The genus is also recorded from the Neotropical region (Trivinho-Strixino et al. 2000).The larvae occur in littoral sediments of small to large water bodies (Epler et al. 2013).

Genus Xenochironomus Kieffer, 1921
A genus with ~ 20 species distributed in the Neotropical, Nearctic, Palaearctic, Oriental, and Australasian regions.The genus was revised by Fusari et al. (2013).The larvae of almost all species are obligate miners in freshwater sponges in standing and flowing waters (Epler et al. 2013).

Genus Xestochironomus Sublette & Wirth, 1972
A genus of more than ten described species that occur only in the Neotropical and Nearctic regions (Pinho and Souza 2013;Bello-González et al. 2016).Known larvae are miners in immersed wood in running waters (Epler et al. 2013).

Genus Zavreliella Kieffer, 1920
A genus with ~ 15 species; according to Fusari et al. (2017), 13 of these are known from tropical South America.The genus was revised by Reiss (1990).Larvae build transportable cases and move among submerged vegetation in standing water, but can also be found in sediments in flowing waters (Epler et al. 2013).(2000).However, this record is incorrect.At closer examination the specimens belong to Zavreliella longiseta Reiss, 1990, a species that lacks dark spots in the wing and has a second, strong, curved spur on the hid tibia.The generic diagnosis given by Reiss (1990) should thus be amended accordingly.

Subfamily Diamesinae
Genus Diamesa Meigen, 1835 A genus of > 100 named species distributed in the Nearctic, Palaearctic, Afrotropical, and Oriental regions.Larvae of Diamesa are generally adapted to cool waters, inhabiting flowing water, springs, and to a lesser extent shallow still water and the hygropetric zone; they can be dominant in the kryon zone of glacier fed streams (Saether and Andersen 2013a).

Genus Pseudokiefferiella Zavřel, 1941
The only included species, Pseudokeifferiella parva (Edwards, 1932), is distributed in the Nearctic and Palaearctic regions.The larvae inhabit small streams and the hygropetric zone (Saether and Andersen 2013a).

Genus Allocladius Kieffer, 1913
A genus of 25 named species that occur in all zoogeographical regions, except Antarctica and Oceania.Andersen et al. (2010) reviewed the South American species; a revision of the genus was given by Ferrington and Saether (2011).
The larvae of Allocladius appear to be truly aquatic, as they have been found in ponds, rivers, and streams, including the shores of brackish water bodies and salt marshes, but some are probably able to survive in moist sandy substrata (Andersen et al. 2013b).

Genus Antillocladius Saether, 1981
A genus of 30 named species that occur mostly in the Neotropical region, but are also found in the Nearctic, Palaearctic, and Oriental regions (Ashe and O'Connor 2012a; Andersen and Hagenlund 2017).The genus was reviewed by Mendes et al. (2004Mendes et al. ( , 2011) ) and Mendes and Andersen (2008).Known larvae from South America appear to be terrestrial or semi-terrestrial as they have been collected in moss and lichens on stones and tree trunks; a North American species has been found in seeps near streams and impoundments (Mendes et al. 2004;Andersen et al. 2013b).(2008: 41); Ashe and O'Connor (2012a: 124).Endemic.

Genus Bryophaenocladius Thienemann, 1934
A species-rich genus with ~ 120 named species that occur in all zoogeographic regions, except Antarctica and Oceania.Neotropical and Mexican species were reviewed by Wang et al. (2006).The larvae of most species are terrestrial or semi-terrestrial, but a few are aquatic (Andersen et al. 2013b).

Genus Cardiocladius Kieffer, 1912
A genus of 20 named species that occur in all zoogeographic regions except Antarctica and Oceania.The Neotropical species were reviewed by Andersen et al. (2016).The larvae live in fast-flowing waters and are often associated with the immature stages of blackflies (Simuliidae), on which they are reported to be predaceous (Andersen et al. 2013b).

Genus Clunio Haliday, 1855
A genus of 25 described species that occur in all zoogeographic regions except Antarctica.The larvae are marine and believed to be omnivorous, feeding on algae and dead or dying animals (Andersen et al. 2013b).

Genus Corynoneura Winnertz, 1846
A genus of ~ 100 named species that occur in all zoogeographic regions except Antarctica.A review of the Neotropical species was given by Wiedenbrug et al. (2012).Larvae occur in virtually all types of aquatic habitats, from standing waters to fast-flowing streams (Andersen et al. 2013b).

Genus Gravatamberus Mendes & Andersen, 2008
A genus with five named species endemic to the Neotropical region.Larvae have been found in bromeliads (Mendes and Andersen 2008).

Genus Mesosmittia Brundin, 1956
A genus of 18 named species that occur in the Neotropical, Nearctic, Palaearctic, Afrotropical, and Oriental regions.The Neotropical and Mexican species were reviewed by Andersen and Mendes (2002b).The immatures are likely terrestrial (Andersen et al. 2013b).

Genus Nanocladius Kieffer, 1913
A genus of 37 named species that occur in all zoogeographic regions except Antarctica.Two subgenera are recognized, namely Nanocladius s. str., and Plecopteracoluthus Steffan, 1965 (see Ashe and O'Connor 2012a).Neotropical species were treated by Wiedenbrug and Silva (2013).Larvae occur in streams, rivers, lakes, and ponds and some are symphoretic on immature Megaloptera and Ephemeroptera (Andersen et al. 2013b).

Genus Onconeura Andersen & Saether, 2005
A genus of eight named species that occur in the Neotropical and Nearctic regions.A review of the genus was given by Wiedenbrug et al. (2009), and a cladistic analysis of the genus was given by Donato et al. (2012).The larvae inhabit streams and rivers (Andersen et al. 2013b).

Genus Paralimnophyes Brundin, 1956
A genus of five named species that occur in the Nearctic, Palaearctic, Oriental, and Australasian regions.The only species with described larvae inhabits eutrophic lowland pools and ditches (Andersen et al. 2013b).

Genus Parametriocnemus Goetghbuer, 1932
A genus of 35 named species that occur in all zoogeographic regions except Antarctica and the Neotropical region.The genus is recorded from South America based on unnamed larvae from Brazil, Colombia, Peru, and Venezuela (Roback and Coffman 1983;Ospina-Torres et al. 1999;Trivinho-Strixino 2011).Larvae of Parametriocnemus are found in springs and in relatively fast flowing cold streams and rivers (Andersen et al. 2013b).

Genus Pseudosmittia Edwards, 1932
A genus of > 100 described species that occur in all zoogeographic regions, except Antarctica.Andersen et al. (2010) reviewed the Neotropical species, and a revision of the genus was given by Ferrington and Saether (2011).Most larvae appear to be semiterrestrial to semiaquatic (Andersen et al. 2013b).
Pseudosmittia forcipata (Goetghebuer, 1921 Andersen and Mendes (2012).Larvae are rheophilic, living on plants and stones in streams and rivers, and are rarely found in the littoral zone of lakes (Andersen et al. 2013b).

Genus Smittia Holmgren, 1869
A species-rich genus with > 80 named species that occur in all zoogeographic regions except Antarctica.Most larvae are terrestrial, occurring in damp soil, but at least one species is aquatic (Andersen et al. 2013b).

Genus Synorthocladius Thienemann, 1935
A genus of eight named species that occur in all zoogeographic regions except Antarctica.The larvae inhabit springs, small to large bodies of flowing water and small bodies or shallow parts of still water (Andersen et al. 2013b).

Genus Thienemanniella Kieffer, 1911
A genus of ~ 55 named species that occur in all zoogeographic regions except Antarctica.The Neotropical species were reviewed by Wiedenbrug et al. (2013).The larvae occur in most lotic habitats, from fast-flowing streams to slow-flowing ditches and rivers (Andersen et al. 2013b).

Subfamily Tanypodinae Genus Ablabesmyia Johannsen, 1905
A genus of nearly 100 described species that occur in all zoogeographic regions, except Antarctica; it is currently the most speciose genus in Tanypodinae.Four subgenera, Ablabesmyia s. str., Asaya Roback, 1985, Karelia Roback, 1971, and Sartaia Roback, 1983 are recognized (see Ashe and O'Connor 2009).Most Neotropical species probably belong in Ablabesmyia s. str., but as pointed out by several authors, many South American species cannot be assigned to a subgenus with certainty, as there are inconsistencies in the establishment of these groups (see Neubern et al. 2013).Many of the recently described species are thus not assigned to a subgenus.The Neotropical species were reviewed by Neubern et al. (2013).The larvae occur in a wide variety of habitats, including small and large standing and flowing waters from cold temperate to warm tropical climate zones (Cranston and Epler 2013).

Genus Alotanypus Roback, 1971
A genus of 11 described species distributed in the Neotropical, Nearctic, Palaearctic, and Australasian regions.Larvae occur in both standing and flowing waters and appear to tolerate a broad range of conditions including very acid waters (Cranston and Epler 2013).

Genus Apsectrotanypus Fittkau, 1962
A genus of seven named species that occur in all zoogeographic regions except Antarctica and Oceania.In South America unnamed species are recorded from Argentina and Colombia (Donato et al. 2008b;Ruiz-Moreno et al. 2000;Spies and Reiss 1996).The larvae inhabit small, cool, flowing waters (Cranston and Epler 2013).

Genus Clinotanypus Kieffer, 1913
A genus of ~ 45 described species that occur in all zoogeographic regions, except Antarctica.Two subgenera are recognized, Clinotanypus s. str.and Aponteus Roback, 1971 (see Ashe and O'Connor 2009.)The Neotropical species were reviewed by Neubern et al. (2014).The larvae prefer soft sediments in shallow, warm water bodies including ponds, lakes and slow-flowing streams and rivers (Cranston and Epler 2013).

Genus Coelotanypus Kieffer, 1913
A genus of ~ 20 described species that occur in the Neotropical, Nearctic, Afrotropical, and Australasian regions.A key to the males of the Neotropical species was given by Paggi and Zilli (2018).The larvae inhabit benthic sediments of lakes, including artificial impoundments, slow flowing reaches of rivers and old riverbeds (Cranston and Epler 2013).The genus can be very abundant in Amazonian flood-plain lakes and in wetlands in southern Brazil (Fonseca Leal et al. 2004;Panatta et al. 2007).

Genus Djalmabatista Fittkau, 1968
A genus of 15 described species that occur in all zoogeographic regions except Antarctica and Oceania.The larvae appear to prefer low alkalinity to weakly acid waters, and may be found in lakes, ponds, springs, large and small rivers, as well as in temperate to tropical lentic and lotic depositional habitats (Cranston and Epler 2013).

Genus Fittkauimyia Karunakaran, 1969
A genus of eight named species that occur in all zoogeographic regions except Antarctica and Oceania.The larvae inhabit rivers and the littoral zone of lakes, generally in tropical and subtropical regions (Cranston and Epler 2013).The larvae live in small, standing water bodies as well as in streams and rivers (Cranston and Epler 2013).

Genus Larsia Fittkau, 1962
A genus of ~ 30 named species that occur in all zoogeographic regions except Antarctica.Neubern and Silva (2011) described two new species from the Neotropical region and presented a checklist of the Larsia species of the world.In the Southern Hemisphere the larvae are associated with both lotic and lentic warm waters (Cranston and Epler 2013).

Genus Natarsia Fittkau, 1962
A genus of six named species distributed in the Nearctic, Palaearctic, and Oriental regions.The larvae of the North American species live in small running waters, perhaps favoring cool water.European species inhabit streams, springs, and the littoral zone of montane or northern lakes and show hygropetric behavior in small, standing waters (Cranston and Epler 2013).

Genus Nilotanypus Kieffer, 1923
A genus of 11 named species distributed in all zoogeographical regions except Antarctica and Oceania.Andersen and Pinho (2019) recently described two new species of Nilotanypus from Brazil.The larvae inhabit flowing waters, especially areas with sandy beds (Cranston and Epler 2013).

Genus Pentaneura Philippi, 1866
A genus of eight named species distributed in the Neotropical and Nearctic regions.Silva and Ferrington (2018) recently reviewed the Neotropical species.
The larvae inhabit a variety of aquatic systems, from small streams and ponds to lakes and bays, occasionally the larvae live in shallow water flowing over bedrock covered with moss, algae, and detritus (Silva and Ferrington 2018).
Pentaneura inconspicua (Malloch, 1915: and López-Toledo (2017: 27).This record is doubtful as the specimen was studied using a stereomicroscope with too low magnification to observe morphological details and no experts were involved in the identification of the specimen.

Genus Psectrotanypus Kieffer, 1909
A genus with seven named species that occur in the Nearctic, Palaearctic, Afrotropical, and Oriental regions.The genus was recorded from the Neotropical region by Fittkau and Reiss (1979), but without specifying a country.The larvae occur in ponds, bogs, small bodies of water and slow-flowing streams (Cranston and Epler 2013).

Genus Thienemannimyia Fittkau, 1957
A genus of ~ 20 named species occurring in the Nearctic, Palaearctic, Afrotropical, and Oriental regions.Unnamed species were reported from Costa Rica by Watson and Heyn (1993).The larvae are found in both lotic and lentic waters (Cranston and Epler 2013).

Genus Zavrelimyia Fittkau, 1962
Syn.: Paramerina Fittkau, 1962. Recently Silva andEkrem (2016) formally placed the genus Paramerina Fittkau as a synonym of Zavrelimyia Fittkau.The genus now comprises ~ 50 named species that occur in all zoogeographic regions except Antarctica.Larvae of Zavrelimyia s. str.are, with few exceptions, more or less cold stenothermic and in temperate regions of the Holarctic primarily inhabitants of sandy or detritus rich sediments of springs and lentic habitats of stream sections close to springs.Larvae of Zavrelimyia (Paramerina) are eurythermic, living in a variety of standing waters of all sizes, but are also present in small lotic habitats including pools in rivers (Cranston and Epler 2013).

Subfamily Telmatogetoninae
Genus Telmatogeton Schiner, 1867 A genus of ~ 30 named species that occur in all zoogeographic regions.Except for a few freshwater species from Hawaii, Telmatogeton larvae are marine and live in the intertidal zone where they construct tubes within green algae such as Enteromorpha (Cranston and Ashe 2013).

Species richness and taxonomic composition
A total of 110 species are listed for Mexico; 52 species in 25 genera belong to the subfamily Chironominae, 30 species in 13 genera to Orthocladiinae, 19 species in nine genera and two valid species that are not placed in a genus to Tanypodinae, five species in two genera to Telmatogetoninae, and two species in one genus to Diamesinae.In addition, there are records of 41 genera without identified species.Of these, 20 genera belong to Chironominae, 12 to Orthocladiinae, eight to Tanypodinae, and one genus to Diamesinae.

Distribution
The number of species recorded from the different states throughout Mexico is very uneven.More than ten species have only been recorded from six states.From Campeche a total of 29 species are recorded, most of them based on material collected during a project in Calakmul Biosphere Reserve (Contreras Ramos et al. 2000).From Veracruz 19 species have been recorded, from Nuevo León 15 species, from Puebla 13 species, from the State of Mexico 11 species and from Morelos ten species.From the remaining states only five or less species have been recorded.In most of the states in central and northern Mexico, as well as those on the Pacific coast, there are no or only a few records (Fig. 1).
The type localities for 34 Chironomidae species are in Mexico; of these, 27 species (25% of the total number of recorded species) are endemic.Twenty-nine species have a Neotropical distribution, 15 are Nearctic or Holarctic, while the remaining 39 species are distributed in both the Neotropical and Nearctic regions or are more widely distributed.
In the previous checklist (Andersen et al. 2000), the number of species listed was 61; so, 49 species have been added during the last two decades.Of these, no less than 25 species belong to the subfamily Orthocladiinae, and the number of Orthocladiinae species has thus increased five times from the five species recorded in 2000.In Chironominae the number of species has increased from 29 species in 2000 to 52 species today; while in the subfamilies Tanypodinae, Telmatogetoninae, and Diamesinae no species have been added since 2000.
Comparing the number of Chironomidae species recorded in Mexico with the number in other neighboring, better studied areas, highlights the need for further studies in Mexico.Oliver et al. (1990) and Oliver and Dillon (1994) listed 206 generic and 1065 species names of Nearctic Chironomidae.More than 700 species of chironomids are listed from southeastern USA, including Alabama, Florida, Georgia, North and South Carolina, and Tennessee, which together comprise approximately 41% of the total area of Mexico (Caldwell et al. 1997).
For the state of California, bordering Mexico and comprising ~ 22% of the area of Mexico, 245 species of chironomids have been recorded (Spies 1999).More than 400 species have been recorded from the state of Florida, which comprises less than 9% of the total area of Mexico (Epler 2019).
No comprehensive checklist for the Neotropical region has been published since Spies and Reiss (1996).However, in an updated checklist for Brazil (Pinho 2022) 658 species in 99 genera are listed.Mendes and Pinho (2016) recently published a checklist for Colombia listing only 30 species of Chironomidae in 16 genera in three subfamilies.In addition, 32 genera and two subfamilies have been recorded from Colombia based on larva, but without identified species.
The 110 species recovered in the present checklist is far from the 1000 species estimated by Andersen et al. (2000) to occur in Mexico and highlights the need for further studies.Most additional species to be found will undoubtedly belong to the subfamilies Chironominae, Orthocladiinae, and Tanypodinae.Chironominae is the most species rich subfamily of Chironomidae and is found in all biogeographical regions except Antarctica.Additional species will mainly be found in slow flowing streams and rivers, lakes and ponds in lowland habitats, but additional species will also be found in streams, rivers and lakes at higher altitudes.Mexican species of some genera, like e.g.Rheotanytarsus Thienemann & Bause, 1913 have been reviewed and new species described.However, there are several species-rich genera in which Mexican material has not or hardly been studied and in genera like Pseudochironomus Malloch, 1915, Tanytarsus Wulp, 1874, and Polypedilum Kieffer, 1912, many more species are likely to be added.The Orthocladiinae is also a very species-rich and widely distributed subfamily that tends to be particularly abundant in streams and rivers in mountainous areas.For some genera, like Antillocladius Saether, 1981, Bryophaenocladius Thienemann, 1934and Mesosmittia Brundin, 1956, Mexican material has been included in reviews of the genera, while other species-rich genera like Corynoneura Winnertz, 1846 and Cricotopus Wulp, 1874, are hardly studied at all.Most additional Tanypodinae species will probably be found in slow flowing streams and rivers, lakes and ponds in lowland habitats.So far only a few genera of Tanypodinae have been studied in detail in Mexico and for several species-rich genera like Ablabesmyia Johannsen, 1905 andLabrundinia Fittkau, 1962, there are only a few species recorded from Mexico so far.
Particularly in Orthocladiinae, several recently described genera like Colosmittia Andersen & Saether, 1994, Litocladius Mendes, Andersen & Saether, 2004, and Titimbera Andersen, Pinho & Mendes, 2015 might also occur in Mexico as they have all been taken in Costa Rica (Andersen et al. 2011a;Mendes et al. 2011;Andersen et al. 2015).There might well be several undescribed genera in the subfamily.Epler (2017) recently recorded no less than 16 undescribed genera of Orthocladiinae from Zurquí in Costa Rica.
Additional species will also likely be found in some of the less species-rich subfamilies.Today, ten extant subfamilies of Chironomidae are recognized.Six subfamilies occur in the Nearctic region, while in the Neotropical region no fewer than nine subfamilies have been encountered.At the subfamily level the Neotropical region is thus the most diverse biogeographical region.Only the monotypic subfamily Usambaromyiinae Andersen & Saether has not been recorded.In the Neotropical region two of the other subfamilies, Chilonomyiinae Brundin and Aphroteninae Brundin, have only been found in southern Chile and Patagonia and it is unlikely that any species in these two subfamilies occur in Mexico.
However, two subfamilies so far not recorded from Mexico might occur in the country.The subfamily Buchonomyiinae Brundin & Saether with three included species is found in the Neotropical, Palaearctic, and Oriental regions.It was recorded for the first time from the Neotropical region by Andersen and Saether (1995) describing Buchonomyia brundini Andersen & Saether, 1995 from a small, shallow, rather fast-flowing river in Costa Rica.The subfamily Podonominae Thienemann & Edwards has a mainly bipolar distribution with five genera and 15 species in North America and Canada, and five genera with altogether 85 species in the southern part of South America.Spies (1999) recorded two species of Boreochlus Edwards, 1938 and one species of Parochlus Enderlein, 1912 from California.Several species have recently also been described from Brazil, and two genera, Podonomus Philippi, 1866 and Parochlus, are listed from Colombia based on larvae (Mendes and Pinho 2016;Pinho 2022).
The subfamily Telmatogetoninae with two genera, Telmatogeton Schiner, 1867 and Thalassomya Schiner, 1856, is marine.Both genera with altogether five species are known from Mexico.
The subfamily Diamesinae has a mainly arctic or alpine distribution with 55 species in ten genera in the Nearctic region and 11 species in five genera in the Neotropical region.Two species of Diamesa Meigen, 1835 were described by Serra-Tosio (1977) from a high-altitude lake in the Mexico State.The genus, with 107 species, is known from the Nearctic, Palaearctic, Afrotropical, and Oriental regions.Spies (1999) listed six species of Diamesa from California and one species in each of the genera Pseudodiamesa Goethgebuer, 1939 andSympotthastia Pagast, 1947.Based on larvae, Mendes and Pinho (2016) listed the genus Paraheptagyia Brundin, 1966 from Colombia.Paraheptagyia, with five species, is distributed in the southern part of the Neotropical region and two species occur in the Australasian region (Ashe and O´Connor 2009).
The uneven distribution of Chironomidae records throughout the states in Mexico clearly reflects the lack of Chironomidae studies.Some Nematocera groups are better studied than the Chironomidae in Mexico.Consideration of the general distribution patterns of these groups may suggest what can be expected for the chironomids.States like Oaxaca and Chiapas are among the richest when it comes to Culicidae, Simuliidae and Ceratopogonidae (Ibánez-Bernal and Coscarón 1996;Ibánez-Bernal et al. 1996).Bond et al. (2014) also demonstrated that the Pacific slope has a high diversity of aquatic insects.Climatic and topographic heterogeneity in southeastern Mexico leads to high environmental heterogeneity (Rodríguez et al. 2019).The area has a complex geology resulting in barriers such as the Isthmus of Tehuantepec that is responsible for increased diversity in several insect groups (Halffter and  Morrone 2017).It is expected that future studies will show that the increase in the number of Chironomidae species will be particularly striking in Oaxaca and Chiapas.
Mexico is known to have a high proportion of endemic species.In well-studied groups like amphibians, reptiles, and mammals the proportion of endemic species is 60%, 51% and 31%, respectively (Hufnagel and Mics 2021).However, the number of records of chironomids from Mexico is clearly insufficient to appreciate patterns of endemism or clear biogeographic relationships.
To increase the number of species recorded from Mexico, taxonomic studies should be given priority.Even though rearing of larvae is important to associate the immatures with adults, chironomids are generally described based on adult males.To achieve an immediate increase in species numbers, further studies should thus focus on adults rather than on larvae and pupae.Fieldwork should be focused particularly on the states in central and northern Mexico, where the chironomid fauna is poorly known.The southeastern states along the Pacific coast should also be given special attention.Different habitats such as streams, rivers, lakes, and ponds should be visited, and collections should be made at different altitudes.Several chironomid species live in special habitats, like phytotelmata, and many species particularly among the Orthocladiinae, are semiterrestrial or terrestrial.
(Cranston and Epler 2013)era are recognized, namely Tanypus s. str.andApelopiaRoback, 1971(seeAshe and O'Connor 2009).The larvae live in sediments in standing and slowly flowing waters, especially in temperate to warm regions, where they can tolerate high salinity(Cranston and Epler 2013).
(Cranston and Ashe 2013)ies that occur in all zoogeographic regions except Antarctica.The larvae live in the intertidal marine zone, particularly in the warmer seas of the world(Cranston and Ashe 2013).