Mimomyia (Mimomyia) chamberlaini Ludlow

Harbach, Ralph E. & Wilkerson, Richard C., 2023, The insupportable validity of mosquito subspecies (Diptera: Culicidae) and their exclusion from culicid classification, Zootaxa 5303 (1), pp. 1-184 : 114-116

Mimomyia (Mimomyia) chamberlaini Ludlow

subspecies chamberlaini Ludlow, 1904b —original combination: Mimomyia chamberlaini . Distribution: Australia, Bangladesh, Cambodia, India, Indonesia, Malaysia, Myanmar, Nepal, Papua New Guinea, People’s Republic of China, Philippines, Sri Lanka, Thailand, Vietnam ( Wilkerson et al. 2021).

subspecies clavipalpus ( Theobald, 1908) —original combination: Radioculex clavipalpus (subspecific status by Mattingly 1957a). Distribution: India, Pakistan, Sri Lanka ( Wilkerson et al. 2021).

subspecies metallica ( Leicester, 1908) —original combination: Conopomyia metallica (subspecific status by Rattanarithikul et al. 2006a). Distribution: Australia, Cambodia, Indonesia, Laos, Malaysia, Papua New Guinea, Philippines, Singapore, Taiwan, Thailand, Vietnam ( Wilkerson et al. 2021).

As the most recent reviser of Mimomyia (as a subgenus of Ficalbia ), Mattingly (1957a) recognized clavipalpus as a subspecies and treated metallica as a variety of chamberlaini . Curiously, Mattingly included chamberlaini sensu stricto and var. metallica in keys for the identification of adult females and males (separate keys), and included only chamberlaini sensu stricto in keys to larvae and pupae. He did not include subspecies clavipalpus in any of the keys. Mattingly & Grjebine (1958), who also recognized Mimomyia as a subgenus of Ficalbia , treated metallica as a species, but explicitly noted that “ F. metallica is probably only a color variety of F. chamberlaini [translated from the French].” It is interesting that Mattingly & Grjebine did not mention clavipalpus , perhaps because their paper was in press when Mattingly (1957a) was published and they also recognized it as a subspecies of chamberlaini . Without comment, Rattanarithikul et al. (2006a) included metallica as a subspecies of chamberlaini in keys to the adults and larvae of the mosquitoes known to occur in Thailand. Prior to these actions, clavipalpus was recognized as a synonym of chamberlaini and metallica was regarded as a separate species ( Edwards 1932a).

Mimomyia chamberlaini was described from a single male collected at Bayamban, Pangasinan, Luzon Island, Philippines ( Ludlow 1904b). Ludlow did not provide illustrations and did not describe the genitalia of the specimen. Four years later, Theobald (1908) described Radioculex clavipalpus from a series of females and males captured at Calcutta, West Bengal, India, but the description did not include illustrations. In the same year, Leicester (1908) described the female and male of Conopomyia metallica from specimens collected at Barrack Pool, Kuala Lumpur, Malaysia. Leicester also did not provide illustrations of the nominal species.

Published records indicate that Mi. chamberlaini sensu stricto occurs in most areas of the Oriental Region and tropical areas of the Australasian Region. As pointed out by Mattingly (1957a), available morphological evidence suggests that chamberlaini sensu stricto and metallica are variants of a single species. His assessment is as follows.

The classical diagnostic character has been the occurrence in F. metallica of median pale markings on the abdominal tergites [terga] and the absence of such markings in F. chamberlaini . In Malaya complete inter-gradation between these conditions has been found to occur. I have specimens with a more or less continuous pale median line on the abdomen, others with this line reduced to one or two small spots on posterior tergites and one with abdomen completely dark above. As already noted… this last specimen is associated with a larval skin [exuviae] having the distal part of the antenna pale while all my other Malayan larvae have the antenna entirely dark. This is another traditional distinction between F. chamberlaini and F. metallica and were no other evidence available one would be inclined to attribute the one specimen to the first species and the remainder to the second. As against this, however, Philippines specimens with all dark abdomen have larvae with all dark antenna. Other larval differences noted by Edwards & Given… will be seen that at best they are partial differences and they seem to represent differences between the Indian and Indomalayan forms rather than between F. chamberlaini and F. metallica as such. The only significant larval variation within the Indomalayan area appears to be the occurrence of an unusually small number of branches in head seta B [seta 6-C] of the Philippines form (3–5, not less than 4 elsewhere) and a tendency for Malayan larvae to approximate to the Indian form [ clavipalpus ] in the reduced number of teeth [scales] in the distal row(s) of the comb (1–8, 3–10 elsewhere) and rather less strongly developed spiculation of the saddle edge. In the adult the only notable colour variation concerns the scaling of the prescutellar area. In most cases this is quite extensively pale scaled. Malayan forms, however, tend to have the pale scaling greatly reduced or even absent and my one New Guinea specimen has this area wholly or largely dark. Australian specimens appear regularly to have this area very extensively pale scaled but I have seen individual specimens with it equally pale from Sumatra, Java and Tonkin [ Vietnam]. I do not think this variation is taxonomically significant.

In view of the striking difference in appearance between well marked specimens of F. chamberlaini and F. metallica it has seemed to me desirable to distinguish the latter as var. metallica , using the term “var.” in the same sense as Edwards (1941: 2) as indicating “bridged variation in one area” as against the geographically representative variation associated with subspecies.

In view of the observations and arguments put forward by Mattingly (1957a), until more evidence becomes available, we believe that metallica should be recognized as a synonymous name; therefore, it is here formally placed in synonymy with that species: metallica ( Leicester, 1908) , junior subjective synonym of Mimomyia (Mimomyia) chamberlaini Ludlow, 1904b. We should add, however, that it would seem likely that Mi. chamberlaini is a complex of species, but as Mattingly aptly stated, “Very much more material is however needed before this can be put forward as more than a most tenuous hypothesis.” For the record, Edwards & Given (1928, Singapore), Galliard & Ngu (1949, Vietnam) and Chen & Lien (1956, Taiwan) treated metallica as a separate species based principally on the characters which Mattingly (1957a) found to be attributable to variation. In agreement here, metallica is not listed as a species in the Encyclopedia of Life.

Mattingly (1957a) had the following to say about clavipalpus .

The Indian form of F. chamberlaini (= Radioculex clavipalpus Theobald ) differs from other forms, so far as can be judged from the limited material available to me, in a number of interesting partial characters of the larva. Thus the antenna is constantly pale on the distal segments in Indian larvae… while in most Indomalayan specimens it is wholly dark. However, I have one larval skin [exuviae] with the Indian type of antenna from Malaya and it may be presumed that the larvae from Tonkin [ Vietnam] provisionally assigned to F. chamberlaini by Galliard & Ngu (1949: 497) also had antennae of this type. It is interesting to find that the Malayan skin is associated with the only adult which I have from that territory with complete suppression of median pale markings on the abdominal tergites [terga]. This is, however, of doubtful significance since the U.S. National Museum has adults from the Philippines with complete suppression of these markings associated with larval skins having wholly dark antennae. Other differences between the Indian form and those occurring in the Indomalayan and Australian areas… [include (in general, using up-to-date terminology) setae 5- and 6-C with more branches, scales in distal row(s) of the comb fewer in number, saddle generally with fewer spicules on the posterior margin and pecten with more spines]. …The number of long spicules on the distal edge of the saddle is to some extent a matter of subjective estimate since some spicules are of intermediate length. However, the difference seems quite clear and constant. …It may be felt that these differences justify distinguishing the Indian form as a separate subspecies.

Based on the adult and larval distinctions exhibited by clavipalpus , and because it has only been found in areas of India, Pakistan and Sri Lanka where chamberlaini and metallica have not been recorded, we feel that this nominal form should be returned to its original specific rank, at least provisionally: Mimomyia (Mimomyia) clavipalpus ( Theobald, 1908 b) . Mimomyia clavipalpus is currently listed as a species in the Encyclopedia of Life.