Culex (Melanoconion), Theobald, Theobald

Torres-Gutierrez, Carolina & Sallum, Maria Anice Mureb, 2015, Catalog of the subgenus Melanoconion of Culex (Diptera: Culicidae) for South America, Zootaxa 4028 (1), pp. 1-50 : 4-10

Taxonomic history of Subgenus Melanoconion

Melanoconion as a formal taxonomic name was proposed by F.V. Theobald in 1903 as a new genus of Culicidae . Its etymology from the Greek words "melanos" which means black; and "konis" meaning dust (Black dust). The original description highlighted the "squamose character of the wings, which are very characteristic" (squamose relates to the latin word squama which means "scale"). Furthermore, in the same reference, the six Melanoconion species were described as "small black gnats which bite viciously and which occur in swamps and woods" ( Theobald, 1903). For several years the status of Melanoconion as a taxon suffered frequent changes that altogether have created a considerable level of confusion to this group of mosquitoes.

In 1905, Blanchard changed the designation from Melanoconion to Melanoconium, though other authors did not follow his version. A year later, Dyar and Knab published a taxonomic contribution to the larvae of Culicidae , in which Melanoconion was treated as a synonym of the genus Culex and Mochlostyrax was created as a new genus with Mochlostyrax caudelli Dyar and Knab, 1906 as its type species ( Dyar & Knab, 1906a). More than a decade later, through the study of male genitalia´s characters, Dyar (1918a) considered 16 subgenera for Culex , with Cacoculex and Choeroporpa as new subgenera, also re-establishing Melanoconion (with seven species) and Mochlostyrax (with two species) as subgenera. Moreover, in a different paper, same year ( Dyar 1918b), he recognized Helcoporpa as another subgenus of Culex .

Later on, Dyar made new arrangements for Culex subgenera, still based on morphological characters of the male genitalia (see "On some of the American subgenera of Culex "; Dyar, 1923a). In such paper, he added and corrected to the subgeneric classification of Culex (i.e., postulating Anoedioporpa instead of Isostomyia for six species, and creating Gnophodeomyia that included two species). But in reality, this publication added to the confusing state of the genus Culex by that time, mainly because the author proposed new groupings for subgenera ( Dyar, 1923a), without properly referring to the previous classification presented for the subgeneric level just a few years earlier ( Dyar, 1918a, b).

By 1928, Dyar published "The Mosquitoes of the Americas", in which made drastic changes to the subgeneric level of Culex . In his monograph, Dyar only kept Mochlostyrax and Melanoconion as subgenera and transferred previously proposed taxa like Helcoporpa, Anoedioporpa, Gnophodeomyia and Tinolestes , as mere sections within subgenera. Moreover, this new arrangement included also two species from the subgenus Micraedes as Dyar transferred them to Melanoconion Section.

Dyar´s classification (1928) can be summarized as follows: Genus Culex

Subgenus Mochlostyrax :

Sections: Dinoporpa ; Helcoporpa ; Choeroporpa ; Mochlostyrax Subgenus Melanconion:

Sections: Tinolestes ; Gnophodeomyia ; Melanoconion ; Anoedioporpa .

Posteriorly, F.W. Edwards (1932) continued to change the already unstable Culex classification. In Edward´s proposal, the genus Culex consisted of 16 subgenera, being Mochlostyrax and Melanoconion some of them. Regarding the latter, Edwards made specific comments about Dyar´s classification; in Edward´s opinion the grouping based on the male style (= gonostylus) were not very sharp and therefore he decided not to adopt Dyar´s groupings within the subgenus. Instead, Edwards divided the subgenus Melanoconion into three groups (A, B, C) based on the color of hind tarsi, shape of the vertex scales and color of mesonotum. Adittionally, Edward´s classification treated Gnophodeomyia, Tinolestes, Helcoporpa ; Choeroporpa ; Dinoporpa and Asebeomyia as synonyms of subgenus Melanoconion . For the subgenus Mochlostyrax the included species were the same as the ones included by Dyar (1928) in the section under the same name. Furthermore, Edwards considered Anoedioporpa as synonym of Isostomyia .

Other significant publication by Komp & Curry (1932), proposed Upsiloporpa as a new subgenus (for a new species haynei from Panama). And more importantly, the revision by Komp (1935), approaching the validity of type species of Melanconion and Mochlostyrax , at least those deposited in the U.S. National Museum, brought a better light to the taxonomic status of these two subgenera. In Komp´s words:

..."Great difficulties were encountered in making determinations, using Dyar´s keys, descriptions and figures. This was particularly true in the subgenera Mochlostyrax and Melanoconion , which have always been accounted difficult groups. Part of the difficulty lay in the inadequacy and inaccuracy of the descriptions of the male terminalia, which are the final resort in specific determinations in these groups" ( Komp, 1935, p. 2, 3).

Sharp comments were made by Komp in this review regarding the inadequacy of Dr. Dyar´s microscope resources as well as his technique to process the delicate male genitalia parts. And then, after reviewing the U.S. National Museum´s type species, 59 out of 75 type species were found as valid; and 16 species were thus indicated as synonyms. One of the findings showed that the recently described, Culex (Upsiloporpa) haynei , in reality corresponded to a badly mounted slide of Cx. (Melanoconion) menytes ( Komp, 1935) .

Further taxonomic corrections and revisions for the subgenera Melanoconion and Mochlostyrax were accomplished by King & Bradley (1937) for some of the species occurring in the United States. Later on, Sevenet & Abonnenc (1939) described new Melanoconion species for French Guiana based basically on male genitalia and larvae characters; following Edward´s classification of Culex . By the same year, Lane (1939) published his catalog of Neotropical mosquitoes, in which he included 10 Culex subgenera occurring in such a region (subgenus Melanoconion with 76 species and subgenus Mochlostyrax with 6 species). In 1943, Lane & Whitman, also adding to the species of Culex , reviewed the taxonomic history of Culex (Microculex) ocellatus and transferred the species to subgenus Melanoconion , describing as well a new species for the subgenus.

Not until 1950, existed a solid review of the subgenus Melanoconion by Lloyd E. Rozeboom and William H. W. Komp, whose work gave stability to this complex taxon. In the words of Rozeboom & Komp:

... "Few if any groups of mosquitoes present greater taxonomic confusion and difficulty than does the subgenus Melanoconion . At the present time the species can be recognized with certainty only by the structures of the male terminalia. The females of most species cannot be separated from one another; they are usually small and darkcolored, only a few having a distinctive golden-scaled scutum or white-ringed tarsi. The larvae of many species are readily recognizable but for the most part they are insufficiently known to permit positive identification" ( Rozeboom & Komp, 1950; p. 75).

In their review, Rozeboom & Komp provided keys and illustrations for the 91 species recognized as part of the subgenus Melanoconion , which meant the removal of Mochlostyrax as a valid subgenus, merging all the species as a single subgenus. Also, they thought as artificial and erroneous Edwards´s (1932) classification of the subgenus, explicitly adopting Dyar´s grouping or sections (except Anoedioporpa ), which were incorporated in their keys to species; with the keys based on several characters of the male genitalia. Also, a group of 11 species were listed as "position and validity unknown" given the lack of information on the required male characters. The proposed changes by Rozeboom & Komp (1950) were followed by Lane (1953) in his monograph on Neotropical Culicidae (vol. 1); with the exception of Tinolestes Section that Lane elevated as a subgenus based on the length of the male palpi.

Subgenus Melanoconion by Rozeboom & Komp (1950):

Sections: Melanoconion , Tinolestes, Gnophodeomyia, Dinoporpa, Helcoporpa ,

Choeroporpa and Mochlostyrax .

Unfortunately, the stability gained after Rozeboom & Komp´s (1950) solid revision, did not last long. In 1952 and 1954, Foote published taxonomic descriptions and keys for larvae and pupae for the subgenera Melanoconion and Mochlostyrax ; his monographs included great morphological descriptions and display of the immatures´s characters. As to the matter of the subgenera, his own words were as follows:

..."After a rather exhaustive study of the morphology and chaetotaxy of the larvae of the subgenus Melanoconion (in the sense of Rozeboon & Komp), the writer has concluded that Dyar and Knab´s genus Mochlostyrax is deserving of subgeneric rank, as suggested by Edwards" ( Foote, 1954, p.5).

Foote´s taxonomic contribution was a big step to identify the immatures of Melanoconion and Mochlostyrax , as he listed 58 species for the former and 8 species for the latter ( Foote, 1954).

During the 60´s and 70´s, the most noteworthy contributions to Melanoconion were by John N. Belkin (1968) and Belkin et al. (1970). In the monograph by Belkin (1968—The type specimens of New World Mosquitoes in European museums), he continued the notion of separating Melanoconion and Mochlostyrax , also re-arranging many of the species included in these and other subgenera of Culex . Belkin transferred species from Tinolestes to Melanoconion ; and made other arrangements (either removing or adding species) to different subgenera such as Aedinus, Anoedioporpa and Micraedes . With the publication of Belkin et al. (1970), the subgenus Mochlostyrax came to an end. The referred authors relegated Mochlostyrax to a section within Melanoconion based on the study of Mochlostyrax pilosus (species previously included in Mochlostyrax ). The entomological community in further publications finally adopted the treatment of Melanoconion as a consolidated subgenus.

In 1977, a couple of authors published the catalog of the mosquitoes of the world (Knight & Stone, 1977), in which 21 subgenera for Culex were considered, keeping the status of Melanoconion as Belkin et al. (1970) did; in this catalog 161 species were listed for the subgenus Melanoconion . In 1980, Berlin and Belkin published a revision of the subgenera Aedinus, Tinolestes and Anoedioporpa of Culex , nonetheless including Melanoconion in their taxonomic keys to separate adults, male genitalia, pupae and fourth-instar larvae of the species in the Americas. Moreover, they presented a very pertinent discussion and re-arranged several species that had in earlier works been included in Melanoconion or other subgenera.

Many contributions on the subgenus Melanoconion were achieved by Sirivanakarn (1978, 1979), Sirivanakarn & Belkin (1980), Sirivanakarn & Degallier (1981), Sirivanakarn and Galindo (1980) and Sirivanakarn & Jacob (1979, 1981a, 1981b). But the most significant of them was indeed the revision of the subgenus Melanoconion (Sirivanankarn, 1983—"A Review of the Systematics and a proposed scheme of internal classification of the New World subgenus Melanoconion of Culex "). Before the revision by Sirivanakarn there were 165 species known in the subgenus, and after his studies and dedicated analysis to this taxon, he presented 149 species divided into three Sections and several groups and subgroups (see Table 1 ).

In Sirivanakarn words:

"The first step in this classification is to recognize several primary groups (groups and subgroups). These primary groups are then assembled into major sections on the basis of the type of basal hook of the lateral plate of the male genitalia, the type of decumbent scales in the center of the vertex and other features of the adults, the position of seta 9-VIII of the pupa and certain combinations of larval chaetotaxy as given in the keys" Sirivanakarn (1983).

In his monograph, Sirivanakarn provided keys to separate groups and subgroups for adults, male genitalia, pupae and larvae. Compared to the previous taxonomic revision of the subgenus by Rozeboom and Komp (1950), Sirivanakarn´s keys lack information on specific levels which is a significant topic when there is an interest in reaching species-level identification of this complex taxon. Sirivanakarn clearly described all the taxonomic characters used in his classification scheme, and further discussions on such characters were included for each of the Sections he proposed (Spissipes, Melanoconion and Ocellatus); however the amount and type of illustrations was rather scarce considering the size of the subgenus.

Posterior to Sirivanakarn´s revision, most of the taxonomic contributions for the subgenus Melanoconion were published by Brazilian specialists that made specific changes to the existent grouping and more importantly added to the knowledge of the species of Melanoconion . Examples of significant contributions can be found in Forattini and Sallum (1985; 1987a,b; 1989a,b,c,d; 1990; 1992a), and Peyton & Harbach (1991), which contain redescriptions of several species or even the determination of new ones; with sound taxonomic studies for females, males and in some cases even for immature stages.

A decade after Sirivanakarn´s work, Pecor et al. (1992) published one of the most influential monographs on subgenus Melanoconion , their "Catalog and illustrated review of the subgenus Melanoconion of Culex ". This catalog, still a very useful taxonomic guide to the subgenus, contains a complete compilation of all the species of Melanoconion described to the year of its publication. Pecor et al. compiled 154 species, with 83 junior synonyms and 13 nomina dubia. One of the most important changes to the taxonomic classification of the subgenus was the removal of Ocellatus Section, explained by Pecor et al. as follows: "We have determined that this group of species ( Culex ocellatus Theobald, 1903 ; Cx. nigrimacula Lane & Whitman, 1943 ; Cx. punctiscapularis Floch & Abonnenc, 1946 ; Cx. flochi Duret, 1969 ) does not belong in the subgenus Melanoconion ". To this date, the Ocellatus Section continues to be without any subgeneric placement.

The catalog by Pecor et al. (1992) does not present any keys to the species or groups but instead included reproductions of original drawings of male genitalic structures, with a couple of species having their genitalia drawn for the first time (i.e., Culex adamesi Sirivanakarn & Galindo, 1980 and Culex crybda Dyar, 1924b ). Moreover, for each one of the species included in their catalog, Pecor et al. presented valid names, type species information, geographical distribution (indicated as a country-list) and the complete synonymy records. This catalog represents an invaluable taxonomic tool for any researcher interested in the subgenus.

The most recent taxonomical contributions to the subgenus were published by Forattini & Sallum (1992a) & Sallum & Forattini (1996). In these monographs, the authors studied the Spissipes Section of the subgenus and based their study on morphological characteristics. In the Revision of the Spissipes Section of Melanoconion , Sallum & Forattini (1996) recognized 22 species making some taxonomic changes needed such as the designation of a synonym ( Cx. alvarezi synonymized with Cx. spissipes ) and the removal of Cx. nicaroensis from Melanoconion , remarking that the species belonged to Culex , without subgeneric assignment. Later, Gonzalez & Rodriguez (2001) proposed the subgenus Nicaromyia to include the species Cx. nicaroensis . Additionally, Sallum & Forattini (1996) provided descriptions of adult females and males and notes on distribution and bionomics of the species. More importantly, these authors provided taxonomic keys to the species level with corresponding illustrations (for adult characters as well as for male genitalia). The outcome regarding the arrangement of the Spissipes Section included eight groups and three subgroups readily characterized (see Table 2 ).

* Sources: Harbach (2011, 2015); Sallum & Forattini (1996).

After the catalog published by Pecor et al. (1992), several new species were described mainly from Brazilian regions such as São Paulo and the Amazon states ( Forattini & Sallum, 1992b, c; 1993, 1995; Sallum et al. 1997; Sallum & Hutchings, 2003; Hutchings & Sallum, 2008). These papers were based mainly on characters of the male genitalia, with complete descriptions of the male adults and for some species such as Culex ikelos Forattini & Sallum, 1995 , and Cx. eknomios Forattini & Sallum (1992b) the immature forms (larvae and pupae) were fully described as well.

Although Sirivanakarn (1983) did not provide taxonomic keys to the specific level, his scheme of classification was always taken into account by the majority of authors who contributed with descriptions and redescriptions of species. Almost all the taxonomic publications have discussed the position of the newly described species in terms of Sirivanankarn´s classification of Sections, Groups and Subgroups. Considering this, the updated classification of the subgenus Melanoconion comprises two sections, 21 groups, 23 subgroups and 160 species ( Table 3 ). The species of Melanoconion are distributed mainly in the Neotropical region (which includes Central America, the Caribbean islands and South America), with some species occurring in the Neartic Region ( United States and northern Mexico).

Tables

TABLE 1. Scheme of classification for subgenus Melanoconion proposed by Sirivanakarn (1983).

Section	Group	Subgroup	Number of species
Ocellatus Section	–	–	4
Spissipes Section
	Spissipes Group		1
	Taeniopus Group	Taeniopus Subgroup	1
		Vomerifer Subgroup	3
		Pedroi Subgroup	4
	Paracrybda Group	Paracrybda Subgroup	2
		Pereyrai Subgroup	1
	Ocossa Group	–	2
	Jubifer Group	–	2
	Faurani Group	–	1
	Nicaroensis Group	–	1
	Lopesi Group	–	1
Melanoconion Section
	Atratus Group	–	7
	Distinguendus Group	Putumayensis Subgroup	3
		Distinguendus Subgroup	7
		Chrysonotum Subgroup	1
		Galindoi Subgroup	1
		Rorotaensis Subgroup	1
	Trifidus Group	–	1
	Saramaccensis Group	–	1
	Erraticus Group	Erraticus Subgroup	3
		Clarki Subgroup	1
		Psatharus Subgroup	1
	Educator Group	–	7
	Intrincatus Group	Intrincatus Subgroup	15
		Eastor Subgroup	1
		Idottus Subgroup	5
		Tecmaris Subgroup	1
		Andricus Subgroup	1
		Penai Subgroup	1
	Bastagarius Group	Bastagarius Subgroup	6
		Iolambdis Subgroup	8
	Evansae Group	–	4
	Inhibitator Group	Inhibitator Subgroup	19
		Egcymon Subgroup	4
		Mulrennani Subgroup	1
	Conspirator Group	–	10
	Pilosus Group	Pilosus Subgroup	4
		Caudelli Subgroup	9
	Peccator Group	–	3
TOTAL SPECIES			149

TABLE 2. Classification of the Spissipes Section proposed by Sallum & Forattini (1996).

Section	Group	Subgroup	Number of species
Spissipes Section
	Spissipes Group	–	1
	Taeniopus Group	–	4
	CrybdaGroup	PedroiSubgroup	5
		Paracrybda Subgroup	2
		Pereyrai Subgroup	1
	Vomerifer Group	–	3
	Ocossa Group	–	2
	Jubifer Group	–	2
	Lopesi Group	–	1
	Faurani Group	–	1
TOTAL SPECIES			22

TABLE 3. Current classification of the subgenus Melanoconion based on records of the published literature*.

Section	Group	Subgroup	Number of species
Melanoconion Section	Atratus Group	–	7
	Bastagarius Group	–	1
		BastagariusSubgroup	9
		Iolambdis Subgroup	8
	Conspirator Group	–	10
	Distinguendus Group	Distinguendus Subgroup	7
		Galindoi Subgroup	1
		Putumayensis Subgroup	3
		Rorotaensis Subgroup	1
	Educator Group	–	7
	Erraticus Group	Clarki Subgroup	1
		Erraticus Subgroup	3
		Psatharus Subgroup	1
	Evansae Group	–	4
	Inhibitator Group	–	1
		Egcymon Subgroup	5
		Inhibitator Subgroup	21
		Mulrenani Subgroup	1
	Intrincatus Group	Andricus Subgroup	1
		Eastor Subgroup	1
		Idottus Subgroup	5
		Intrincatus Subgroup	16
		Penai Subgroup	1
		Tecmaris Subgroup	1
	Peccator Group	–	3
	Pilosus Group	Caudelli Subgroup	9
		Pilosus Subgroup	4
	Saramaccensis Group	–	2
	Trifidus Group	–	1
	Undetermined Group		2
Melanoconion species			137
Spissipes Section	Crybda Group	Paracrybda Subgroup	2
		Pedroi Subgroup	5
		Pereyrai Subgroup	1
	Faurani Group	–	1
	Jubifer Group	–	2
	Lopesi Group	–	1
	Ocossa Group	–	2
	Spissipes Group	–	1
	Taeniopus Group	–	4
	Vo m e r i f e r G r o u p	–	4
Spissipes species			23
Total			160