PROC. ENTOMOL. SOC. WASH. 107(3), 2005, pp. 548-553

CULEX MALARIAGER, N. SP. (DIPTERA: CULICIDAE) FROM DOMINICAN : THE FIRST MOSQUITO VECTOR OF PLASMODIUM

George Poinar, Jr.

Department of Zoology, Oregon State University, Corvallis, OR 97331, U.S.A. (e-mail: [email protected])

Abstract. —A new species of fossil mosquito, Culex malariager (Culicidae: Diptera), is described from Dominican amber. This species differs from extant members of the genus by the following combination of characters: 1) proboscis shorter than antennae; 2) wing scales both long and narrow and short and broad; 3) base of R vein (remigium) with two groups of dorsal setae; 4) clypeus as long as broad; 5) empodium on foretarsus; 6) vein 2A with rows of erect, short setae, and 7) postgenital lobe covering base of cerci. Inside the body cavity of C malariensis are various stages (oocysts, sporozoites, ookinete, and microgametocyte) of a Plasmodium malarial parasite. This is the first record of a fossil mosquito vector of a vertebrate pathogen.

Key Words: Culex malariager n. sp., Culicidae, Dominican amber, malaria vector, Plas- modium

During an ongoing investigation of fossil Vincent and MacPhee 1996) and the earliest haematophagous insects, a species of Culex as 45—30 mya based on coccoliths (Cepek in Dominican amber was discovered to con- in Schlee 1999). What makes dating of the tain sporogonic stages of a Plasmodium amber difficult is that it is secondarily de- within its body cavity. The description of posited in turbiditic sandstones of the Up- the Plasmodium will be reported in a sep- per to Lower Miocene Mamey arate paper (Poinar, in press). The present Group (Draper et al. 1994). The spe- study describes this fossil mosquito as a cies that formed the amber is a member of new species in the genus Culex L. the legume family ( protera Although not abundant, fossil culicids Poinar 1991) and the original environment are known from Tertiary amber (Poinar was similar to a present day moist tropical 1992) and a single specimen has been de- forest (Poinar and Poinar 1999). scribed from amber, along with a critical synopsis of previously described Materials and Methods fossil mosquitoes (Poinar et al. 2000). The piece of amber originated from Whereas is Culex the most common genus mines in the northern area of the Dominican of mosquitoes in Dominican amber (Poinar Republic, between the cities of Puerto Plata and Poinar 1999), the only described mos- and Santiago. It is trapezoidal in outline, quito from these deposits is Anopheles measuring 14 X 17 X 25 X 15 mm on the dominicanus Zavortink and Poinar, 2000. sides, 5 mm in thickness and weighs 2 Dating of Dominican amber is still contro- grams. Observations and photographs were versial with the latest proposed age of 20- made with a Nikon stereoscopic microscope 15 mya based on foraminifera (ItuiTalde- SMZ-10 R and Nikon Optiphot® at mag- VOLUME 107, NUMBER 3 549 nifications up to 600 X. All measurements Thorax: Length 1.22 mm; antepronotum are in microns unless otherwise noted. narrow, with 6 aveoli; scutal fossa (pres- The fossil female mosquito is essentially cutum) with 6 aveoli; scutum with both se- complete, but somewhat distorted with tae and alveoli; scutellum (length 85 jxm; many scales and bristles detached (except width 372 (xm) with 3 lobes bearing 10 av- for those on the wings). Only three legs are eoli; no spiracular, post- spiracular, acros- attached to the body (both forelegs and one tichal or postnotal setae; 3 prealar setae and midleg), however the others are adjacent to 4 aveoli on mesokatepisternum; 2 lower the specimen. The thorax and abdomen are mesepimeral setae; wing length 2.7 mm, partially cleared, thus making it possible to greatest width 0.7 mm; microtrichia pre- see internal structures. Since the fossil sent, posterior margin of wing with fringe could not be identified with any extant spe- of scales; wing banding not visible; cell R^ cies it is described as a new species below. longer than its stem (R .+3); cell M almost twice as long as its stem; br and bm cells Culex malariager Poinar, new species extend to middle of wing; anal vein termi- (Figs. 1-10) nates well past fork of CuA; plume scales Description. —Size small, head bent on veins R^ and R, narrow to slightly wid- down partly under thorax; length from ened; Sc and R contiguous for 360 jxm from pronotum to tip of abdomen 2.9 mm (how- wing base; base of vein R with 2 groups of ever head, thorax and abdomen measured dorsal setae; group 1 with 7 setae 32-79 separately, length 4.1 mm). |xm long occurring 204 fxm from wing base, Head: Length 0.59 mm, width 0.66 mm; group 2 with 8 setae 23-57 |xm long oc- vertex and occiput bearing 76 large aveoli curring 45 (xm from wing base; veins Rs

(38 on each side; positions vary slightly and R 4+5 without basal spurs; crossveins from side to side); clypeus rounded in front, without scales; r-m distad to m-cu; alula without scales or setae, length 136 jxm, (length 196 fxm) with outer row of scales; width 133 jxm; eyes nearly contiguous with no setae on lower surface of wing at base narrow interocular space; eye facets mea- of subcostal vein; scales on wing veins vary suring approximately 18 x 21 [xm; maxil- in length and breadth, scales on vein R. R lary palpus with 3 palpomeres, no banding R2 and R3, distal portions of veins A 2+3, , obvious, palpomeres 2 and 3 bear setae and and CuA long and narrow, scales on R,, R I few small scales, palpomere 1 and palpifer 4+5, M|, M2 and basal portions of vein A, bare; lengths, palpomere 1 (with palpifer) and CuA, short and broad; other veins with

95 |xm; palpomere 2, 123 jxm; palpomere intermediate scales; vein 2A without scales 3, 155 |xm; proboscis length 1.53 mm, pro- but bearing rows of short setae 7-10 (xm in boscis covered with mostly broad, but some length (setae differ in structure and size narrow scales; labellum length 136 |xm, la- from wing microtrichia); halter length 315 bellum width 35 (xm; distal and proximal |xm; legs brown-scaled, no pattern or or- sclerites of labellum apparently fused; lig- namentation visible; forecoxa with few al- ula pointed; antenna length 1.90 mm; scape veoli near apex; forefemur swollen slightly bare, length 32 |xm; pedicel globose, with at base, length 1.38 mm; forctibia I.S mm; few setae; pedicel length 116 ixm, pedicel ventral surface of foretarsomcro 1 with width 123 |Jim; flagellomeres verticillate, short spine, opposite surface with scales however most setae absent; basal and ter- and longer spines; length of tarsomeres of minal flagellomeres equal in length; lengths right fore tarsus; 1. 1.5 mm: 2. 0.57 mm; 3, of flagellomeres: 1, 175 ixm; 2, 140 ixm; 3, 0.36 mm; 4. 0.157 mm; 5. 0.14 mm: claw 168 |Jim; 4, 161 (xm; 5, 161 fxm; 6. 154 ixm; length 50 fxm; puhillus length 20 |xm; for- 7, 147 |xm; 8, 154 ixm; 9, 154 (xni;10. 140 elarsus with slender empodium arising be- \Lm; 11, 98 ixm; 12, 105 ixm; 13, 175 |xm. tween piihilli, its filament short with a sin- WASHINGTON 550 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF

Figs. 1-4. Ciilex malariager in Dominican amber. 1, Anterolateral \ie\\. Bar = 0.9 mm. 2, Scales at the base of veins R2 and R3. Bar = 45 |xm. 3, Labella with prementum (P), closely adjacent distal and proximal sclerites (S) and ligula (L). Bar = 45 |xm. 4, Foretarsomere with simple claw (C), pulvillus (P) and empodium (arrow). Bar = 23 |xm. Insert shows a portion of vein 2A bearing rows of short, erect setae. Bar = 30 |xm. VOLUME 107, NUMBER 3 551

Figs. 5—10. Culex malariager in Dominican amber. 5, Right wing (ventral view) with venation. Bar = 210

|xm. 6, Dorsal surface of head with aveoli on occiput and vertex. Bar = 70 (jim. 7, Cerci. postgenital lobe, and gonotreme. Bar = 49 [xm. 8, Right flagellomeres. Bar = 252 |xm. 9, Aveoli on antepronotum. Bar = 70 (xm.

10, Aveoli on trilobed scutellum. Bar = 114 ijim.

gle branch, basal sclerite not visible, em- very numerous long setae and scales sur- podium not seen on mid- and hindtarsi, all rounding cerci; cercus length 50 fxm; cercus pulvilli with fine setae on lower surface; width at base 26 jjim; postgenital lobe large. midtarsomere 5 length 0.13 mm; claw covering bases of cerci. length 46 fxm; pulvillus length 17 |xm; Ratios: Palpus to proboscis 0.24; pro- hindtarsomere 5 length 0.15 mm; claw boscis to antenna 0.81; palpus to clypeus

length 23 [xm; pulvillus length 18 [xm; all 2.7; proboscis to forefemur 1 . 1 I ; clypeus to claws paired, simple, equal. pedicel 1.17. Abdomen: Length 2.3 mm; covered with Material examined.—Holotype renialc in mostly short, broad scales; tergum 8 with Dominican amber, deposited in the Poinar .

552 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON amber collection maintained at Oregon Wyoming and C. winchesteri Cockerell, State University (accession number D-7- 1919 from Eocene deposits in Colorado. 6B). Neither of these is similar to C. malariager. Type locality.—La Toca amber mine in There were two other hematophagous in- the Dominican Republic. vertebrates in the same piece of amber, a Etymology.— "malariager" is based on triatomid bug and a female Ornithodorus the vector association of the fossil mosquito dominicana Poinar, 1995. The presence of with Plasmodium. It is formed with the Lat- these three suggests that the resin in suffix -ger meaning bear, carry or have. was produced in or close to a domicile of Diagnosis. —The following characters vertebrates, which probably served as hosts place C. malariager in the genus Culex: 1) to these parasites. Since the stages of the short palps; 2) tip of abdomen blunt; 3) scu- malarial parasite inside C. malariager re- tellum trilobed with each lobe bearing sep- semble those of an extant avian Plasmodi- arate tufts of setae; 4) no spiracular or um species (Poinar, in press) and it is postspiracular setae; 5) short, partly con- known that Culex transmit avian malaria cealed cerci; 6) claws simple; 7) pulvilli (Riper et al. 1994), at least one of the ver- present; 8) vein lA long; 9) wing microtri- tebrate hosts of C. malariager was a bird. chia distinct; 10) eyes nearly contiguous; This is the first record of a fossil mosquito 11) terga and sterna II-VII uniformly vector of a vertebrate pathogen. scaled; 12) cell R2 longer than vein R2+3; Acknowledgments and 13) hairs on underside of costal vein absent. It is not possible to assign this spe- I thank Tom Zavortink for discussions on cies to an extant subgenus since these taxa mosquito systematics and literature and are defined on the types of scales found at reading a draft copy of this manuscript and particular locations, scale and setal posi- Roberta Poinar for comments on the man- tions on the thorax, and color of scales, ab- uscript. I also appreciate the help of two domen and pleural integument (Berlin and anonymous reviewers. Belkin 1980, Casal and Garcia 1968, Har- Literature Cited bach and Peyton 1992), most of which can- not be determined in the fossil. Berlin, O. G. W. and J. N. Belkin. 1980. Mosquito studies (Diptera, Culicidae). XXXVI. Subgenera The species can be distinguished from Aedimts, Tinolestes and Anoedioporpa of Culex. extant Culex by the following combination Contributions of tiie American Entomological In- of characters: 1) proboscis shorter than an- stitute (Ann Arbor) 17(2): 1-104. tennae; 2) wing scales both long and narrow Casal, O. H. and M. Garcia. 1968. Culex (Allimanta), and short and broad; 3) base of vein R (re- nuevo subgenero para Culex (Culex) tramazay- guesi Duret, 1954 (Diptera, Culicidae). Physis migium) with two groups of dorsal setae; (Bueno Aires) 27: 329-335. 4) clypeus as long as broad; 5) empodium Cockerell, T. D. A. 1919. The oldest mosquitoes. Na- on foretarsus; 6) vein 2A with rows of ture 103: 44. erect, short setae; and 7) postgenital lobe Draper, G., P. Mann, and J. F. Lewis. 1994. Hispaniola, covering base of cerci. Especially signifi- pp. 129-150. In Donovan, S. and T A. Jackson, eds. Caribbean Geology: An Introduction. The cant are items 3 and 6 since they do not University of the West Indies Publishers' Associ- appear to have been reported previously on ation, Kingston, Jamaica. any Culex spp. (Tom Zavortink, personal Harbach, R. E. and E. L. Peyton. 1992. A new sub- communication) genus of Culex in the Neotropical Region (Dip- tera: Culicidae). Mosquito Systematics 24: 242- Discussion 252. Iturralde- Vincent. M. A. and R. D. E. MacPhee 1996. Two other Culex fossils are known from Age and Paleogeographic origin of Dominican North America, C damnatorum Scudder, amber Science 273: 1850-1852.

1890 from Eocene Green River deposits in Poinar Jn, G. O. 1991. Hymenaea protera sp. n. (Leg- VOLUME 107, NUMBER 3 553

uminoseae, Caesalpinioideae) from Dominican Culicidae) n. gen., n.sp., from Cretaceous Cana- amber has African affinities. Experientia 47: dian amber, with a summary of described fossil 1075-1082. mosquitoes. Acta Geologica Hispanica 35: 119- 128. . 1992. Life in Amber. Stanford University Riper III, C. van, C. T. Atkinson, T. Seed. 1994. Press, Stanford, California, 350 pp. and M. Plasmodia of Birds, pp. 73-140. In Kreier, J. P. . 1995. First fossil soft ticks, Onuthodoros an- ed. Parasitic Protozoa (2"'' Edition), Vol. 7. Aca- tiquus n. sp. (Acari: Argasidae) in Dominican am- demic Press, San Diego. ber, with evidence of their mammalian host. Ex- Schlee, D. 1990. Das Bernstein-Kabinett. Stuttgarter perientia 51: 384-387. Beitrager fur Naturkunde, Sen C. Vol. 28: 100 pp. . In press. Plasmodium dominicana n. sp.. Scudder, S. H. 1890. The Tertiary insects of North (Plasmodiidae: Haemospororida) from Tertiary America. Report of the United States Geological Dominican amber. Systematic Parasitology. survey of the Territories 13: 1-734. Poinar, Jr., G. O. and R. Poinar. 1999. The Amber For- Zavortink, T. J. and G. O. Poinar, Jr., 2000. Anopheles est. Princeton University Press, Princeton, 239 pp. (Nyssorhynchiis) dominicamis sp. n. (Diptera: Cu- Poinar, Jr., G. O., T. J. Zavortink, T. Pike, and R A. licidae) from Dominican amber Annals of the En- Johnston. 2000. Paleoculicis miniitus (Diptera: tomological Society of America 93: 1230-1235.