A first record of Aptilotus Mik (Diptera: Sphaeroceridae) from the neotropical region, with the description of three new wingless species of the Aptilotus paradoxus group from high elevations in Costa Rica

8 Pages·1997·3.6 MB·

by  S A Marshall

PROC. ENTOMOL. SOC. WASH.
99(3), 1997, pp. 505-512
A FIRST RECORD OF APTILOTUS MIK (DIPTERA: SPHAEROCERIDAE)
FROM THE NEOTROPICAL REGION, WITH THE DESCRIPTION OF
THREE NEW WINGLESS SPECIES OF THE APTILOTUS PARADOXUS
GROUP FROM HIGH ELEVATIONS IN COSTA RICA
S. A. Marshall
Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada
NIG 2W1.
—
Abstract. The genus Aptilotus Mik is recorded from the Neotropical Region for the
first time.Aptilotus nigritibia, new species, A. nigrimera, new species, andA. zumbadoi,
new species, all completely wingless, are described from ca. 3,000 m in Costa Rica. A
key to the Costa Rican Aptilotus is provided.
Key Words: Diptera, Sphaeroceridae, Limosininae, wing loss, zoogeography, taxonomy,
Costa Rica
The genus Aptilotus, named for the sin- on sternite 5; body usually black, shining
gle wingless European species, A. para- and punctate; female tibia with only an
doxus Mik, is a primarily Holarctic group apical bristle; dorsocentral bristles in 2
in which wing reduction has occurred in- pairs but anterior pair often small; sursty-
dependently within at least five lineages lus ofcharacteristic shape, divided into an
(Marshall 1983, Marshall and Smith outer setose part and an inner part with 1
1990). Twelve described species ofAptil- or (usually) 2 stout bristles.
otus are Nearctic, one species is described All known Central American Aptilotus
from Europe, one is described from Ethi- can be distinguished from other wingless
opia, four are from Nepal, two are from Central American Sphaeroceridae not
southeast Asia, and a group of seven only by the defining characters of Aptil-
closely related species are restricted to the otus as outlined above, but also by the
Canary Islands. There were no known plesiomorphic possession of two orbital
Neotropical Aptilotus prior to the discov- bristles. Other wingless Central American
ery of the three new wingless species de- sphaerocerids, most of which belong to
scribed herein, all of which are endemic the genus Pterogramma, have only a sin-
to high elevation sites in Costa Rica. gle orbital bristle.
Aptilotus species can be apterous, bra-
chypterous, or polymorphic for wing de- Relationships
velopment, with aptery having evolved The species described here belong to
independently in each of the species the paradoxus group of Marshall (1983)
groups recognized by Marshall (1983). with which they share the following syn-
The genus can be diagnosed by the fol- apomorphies: distiphallus elongate, com-
lowing characters: male with a translu- prised of distinctive dorsal and ventral
cent, usually quadrate posteromedial lobe loops and a broad, bilobed membranous
)
506 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
and microspinulose apex; outer posterior er relatively high elevation sites in the in-
part of surstylus long-setose; anterior sur- tervening area, current data show a dis-
stylar spur characteristically flattened, of- junction between the cluster of endemic
ten scale-like. Delimited on the basis of Aptilotus in Costa Rica and their nearest
these characters, the paradoxus group in- relatives in western North America. Other
cludes a clade of 6 brachypterous and one high elevation collections in Costa Rica
macropterous species restricted to the Ca- have yielded wingless Sphaeroceridae,
nary Islands {A. beckeri and related spe- but only in primarily Neotropical clades
cies), an apterous European species (A. related to Pterogramma Spuler. Similarly,
paradoxus Mik), three macropterous spe- sphaerocerid samples available from leaf
cies from Nepal {A. glabrifons Marshall, litter collections from other high-eleva-
A. spinistylus Marshall, A. rufiscapus tion Central American sites have included
Marshall), two macropterous eastern a diversity of undescribed Pterogramma
North American species {A. pogophallus but no Aptilotus. Habitat at these sites
Marshall and A. nigriphallus Marshall), a ranged from mixed oak-pine forests at
macropterous species in Japan {A. longi- 2800 m (Oaxaca, Mexico) to high eleva-
nervis Hayashi), a dimorphic western tion cloud forests at elevations from
North American species (A. luctuosus 2300-2800 m (Chiapas, Mexico; Quezal-
fSpuler)) and two brachypterous western tenango, Guaemala; El Salvador; Cerro
North American species (A. nigriscapus Chiriqui, Panama). Also, no South Amer-
Marshall, A. luteoscapus Marshall). The ican Aptilotus are known, despite collec-
new Costa Rican species all seem to be tion efforts in apparently suitable habitat
closely related to a clade including Eu- in the paramos ofEcuador and Venezuela.
ropean and western North American spe- Despite the lack of Mexican and Cen-
cies which have relatively short female tral American records outside Costa Rica,
cerci and quadrate, bilobed posteromedial further sampling at higher elevations than
areas on male stemite 5. those sites from which samples are cur-
Although all Aptilotus exhibit an unusual rently available are likely to reveal addi-
degree of morphological uniformity, the tional Aptilotus species. It is hypothesized
Costa Rican species seemto represent adis- that Aptilotus is a primarily northern
tinct clade, weakly supported on the basis group, present in the Neotropical region
of the shape of stemite 5 of the male, the as far south as lower Central America (but
sclerotized part of which is very short me- not into South America), where it exhibits
dially, and stemite 8 of the female, which a highly disjunct distribution restricted to
is reduced and modified. Within the Costa cool temperate conditions at elevations
Rican Aptilotus clade, nigrimera plus zum- above 2500 m.
badoi form a monophyletic group, strongly
supported by the possession of a third sur-
Key to the Costa Rican Species of
stylar bristle and the loss of bristles from
Aptilotus
tergite 9 of the female.
Discussion I. Legs mostly black, trochanters and mid and
hind tarsi brown; antenna black. Female ster-
All of the species described here were nite 8 very small, transverse (Fig. 14). Female
collected on Cerro de la Muerte, at a cold tergite 9 with two bristles (Fig. 16). Surstylus
paramo-like site at 3300 m, or in high el- with 2 short, thick ventral bristles (Fig. 11
evation forests (2600 m and above) within Aptilotus nigritibia, n. sp.
- Legs luteous, antenna variable. Femalestemite
a few kilometres of Cerro de la Muerte.
8 with an elongate anterior portion (Figs. 6,
Although it seems likely that related spe- 22). Female tergite 9 bare (Fig. 8). Surstylus
cies occur, or previously occurred, at oth- with 3 short, thick ventral bristles (Figs. 4, 20) . .
J
VOLUME 99, NUMBER 3 507
2. Antenna black, legs mostly luteous. Part of thick posteroventral bristle and a long, thick
frons and body bare and shining. Middle ven- ventral bristle inserted much closer to pos-
tral surstylar bristle inserted close to postero- teroventral than anteroventral bristle. Gon-
ventral surstylarbristle (Figs. 1,4)
Aptilotus nigrimera, n. sp. ostylus almost parallel sided, thick, distal
- Antenna and legs mostly luteous. Frons and part tapered. Basiphallus short, quadrate.
body entirely pruinose, without shining areas. Distiphallus with dorsal (functionally ven-
Middle ventral surstylar bristle mid way be- tral) sclerite with a broad basal part, a nar-
tween anteroventral and posteroventral surstylar row intermediate section and a distally
bristle (Figs. 17, 20) . . Aptilotus zumbadoi, n. sp. forked part; ventral sclerite with a broad
Descriptions of Costa Rican Aptilotus base and broad distal loop; membranous
Aptilotus nigrimera Marshall, new part of distiphallus with long distal dorsal
SPECIES lobes covered with f—lattened setulae.
(Figs. 1-8) Female abdomen. Tergite 8 black, long,
with a shallow anterior notch. Tergite 9
—
Description. Body length 2.5-3.0nini. pale, with a short, transverse, anterior part
Body shining black; fore tarsus pale brown, and a large posterior part narrowly fused
legs otherwise yellow; antenna black to with cerci, surface bare (the usual 2 bristles
dark brown. Middle part of frons mostly absent). Cerci pale, shorter than tergite 9.
bare and shining, ocellar triangle setulose Stemite 8 long and narrow, posterior part
but flanked by bare areas, interfrontal area slightly enlarged with 4 small bristles. Ster-
with only a few setulae medially. Interfron- nite 9 broad, setulose except lateral ex-
tal bristles in 2-3 thin, subequal pairs. Eye tremes. Two internal vaginal sclerites pres-
height4.0X genal height. Dorsocentralbris- ent in addition to large, thin-rimmed rings
tles in two postsutural pairs, anterior pair joined by a discontinuous transverse piece
only slightly longer than acrostichal setulae, (spectacles-shaped sclerite of Rohacek,
prescutellar pair long; only 2-3 rows of ac- 1983). Spermathecae spherical, sclerotised
rostichal setulae between dorsocentral ar- parts of ducts slightly longer than sperma-
eas. Scutellum almost transverse, twice as thecal bod—y.
wide as long. Mid tibia with a long anter- Types. Holotype S,INBio) and 5 para-
(
odorsal bristle proximally, a long distal dor- types (3c?,2$,GUE): COSTA RICA. Car-
sal bristle, and short anterodorsal and pos- tago Province, km. 89 Highway 2, Cerro de
terodorsal distal bristles. Ventral surface of la Muerte, 10.ii.1995, aspirated among
tibia with only an apical bristle in both sex- bamboo litter, S.A. Marshall. Paratype
es. Wing and halter—completely absent. (d,GUE) same as above, but sifted by R.S.
Male abdomen. Tergite 1+2 longer Anderson.
—
than other tergites, uniformly dark. Stemite Etymology. The specific epithet refers
5 with anterior and posterior margins to the dark antenna, a diagnostic character
strongly curved, anterior margin with with separatingA. nigrhnera from the closely re-
shallow medial notch; posteromedial pale lated A. zumbadoi.
part of stemite extending back to anterior
margin of stemite so that pigmented part of Aptilotus nigritibia Marshall, new
SPECIES
stemite is very short medially, pale poster-
omedial section with brown pigmentation (Figs. 9-16)
—
medially, rounded and narrowly notched Description. Body length 2.0-2.5mm.
posteromedially; pale area flanked by clus- Body almost entirely heavily pruinose,
ters of bristles. Surstylus broad, with thin black; fore tibia and tarsi black, other tarsi
bristles on a posterolateral bulge or ridge brown, legs otherwise yellow; antenna yel-
and 3 thick ventral bristles; a flattened, low to pale brown. Head entirely pminose,
broadly bifid anteroventral bristle, a short. without shining areas. Interfrontal bristles
508 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
Figs. 1-8. Aptilotus nigrimera. \, Male terminalia, left lateral. 2, Aedeagus and associated structures,
left lateral. 3, Distiphallus, ventral view. 4, Surstylus, ventral view. 5, Sternite 5 of male. 6, Female ter-
minalia, ventral. 7, Spermathecae and associated sclerites. 8, Female terminalia, dorsal. Abbreviations: gs
= gonostylus (paramere ofearlier papers); T9 = tergite 9 (epiproct ofearlier papers).
in 2-3 thin, subequal pairs. Eyeheight4.5X much longer; 4 rows of acrostichal setulae
genal height. Dorsocentral bristles in two between dorsocentral areas. Scutellum al-
postsutural pairs, anteriorpair twice as long most transverse, twice as wide as long. Mid
as acrostichal setulae, prescutellar pair tibia with a long anterodorsal bristle prox-
VOLUME 99. NUMBER 3 509
Figs. 9-16. Aptilotus nigritibia. 9. Male terminalia, left lateral. 10, Aedeagus and associated structures, left
lateral. 11, Distiphallus, ventral view. 12, Surstylus, ventral view. 13, Stemite 5 ofmale. 14, Female terminalia,
ventral. 15, Spermathecae and associated sclerites. 16, Female terminalia, dorsal.
imally, a long distal dorsal bristle, a short strongly curved, anterior margin with shal-
anterodorsal distal bristle and a smallerpos- low anteromedial notch; posteromedial pale
terodorsal distal bristle. Ventral surface of part of stemite extending back to anterior
tibia with only an apical bristle in both sex- margin of stemite so that pigmented part of
es. Wing and halter—completely absent. stemite is very short medially; pale poster-
Male abdomen. Tergite 1+2 longer omedial section with brown pigmentation
than other tergites, uniformly dark. Stemite medially, rounded and narrowly notched
5 with anterior and posterior margins posteromedially; pale area flanked by clus-
510 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
ters of bristles. Surstylus broad, with thin in 2-3 thin, subequal pairs. Eye height4.5X
bristles on a posterolateral bulge or ridge genal height. Dorsocentral bristles in two
and 2 thick ventral bristles; a flattened an- postsutural pairs, anterior pair twice as long
teroventral bristle and a short, thick pos- as acrostichal setulae, prescutellar pair
teroventral bristle; a very small ventral bris- much longer; 4 rows of acrostichal setulae
tle inserted close to posteroventral bristle. between dorsocentral areas. Scutellum al-
Gonostylus of medium width and weakly most transverse, twice as wide as long. Mid
S-shaped, distal part expanded. Basiphallus tibia with a long anterodorsal bristle prox-
short, quadrate. Distiphallus with dorsal imally, a long distal dorsal bristle, a short
(functionally ventral) sclerite with a broad anterodorsal distal bristle and a smallerpos-
basal part, a narrow intermediate section terodorsal distal bristle. Ventral surface of
and a distal loop which is not closed dis- tibia with only an apical bristle in both sex-
tally; ventral sclerite with a broad base and es. Wing and halter—completely absent.
broad distal loop; membranous part of dis- Male abdomen. Tergite 1+2 longer
tiphallus with long distal dorsal lobes cov- than other tergites, uniformly dark. Sternite
ered with conspicuo—us flattened setulae. 5 of uniform length, neither anterior nor
Female abdomen. Tergite 8 black, long, posterior marging strongly curved, anterior
with a shallow anterior notch. Tergite 9 margin with broad medial notch; postero-
pale, with a short, transverse, anterior part medial pale part of sternite extending back
and a large posterior part narrowly fused almost to anterior margin of sternite, with
with cerci and with 2 dorsal bristles. Cerci elongate brown pigmentation medially,
pale, shorter than tergite 9. Sternite 8 small, quadrate and narrowly notched posterome-
transverse, with 4 small bristles. Sternite 9 dially; pale area flanked by clusters ofbris-
broad, setulose except lateral extremes. In- tles. Surstylus broad, with thin bristles on a
distinct vaginal sclerites present in addition posterolateral bulge or ridge, and 3 thick
to large, thin-rimmed ringsjoined by a dis- ventral bristles; a flattened anteroventral
continuous transverse piece (spectacles- bristle, a short, thick posteroventral bristle
shaped sclerite of Rohacek 1983). Sper- and a ventral bristle midway between the I
"
mathecae spherical, sclerotised parts of other two. Gonostylus thin, of uniform
ducts slightly longer than spermathecal width and weakly S-shaped. Basiphallus
body. — short, quadrate. Distiphallus with dorsal
Types. Holotype (c?,INBio) and 2 para- (functionally ventral) sclerite with a broad
types (lc?,l9,GUE): COSTA RICA: Car- basal part, a narrow intermediate section
tago Province, km. 89, Highway 2, Cerro and a distal loop; ventral sclerite with a
de la Muerte, 10.ii.1995, aspirated among broad base and broa—d distal loop.
bamboo litter,—S.A. Marshall. Female abdomen. Tergite 8 long, bare
Etymology. The specific epithet refers and shining medially and anteriorly, with a
to the black tibia which differentiatesA. ni- shallow anterior notch. Tergite 9 pale, with
gritibia from Costa Rican congeners. a short, transverse, anterior part and a large
posterior part narrowly fused with cerci,
Aptilotus zumbadoi Marshall, new
surface bare (the usual 2 bristles absent).
SPECIES
Cerci slightly longer than tergite 9. Sternite
(Figs. 17-24) 8 long and narrow, posterior part separate
—
Description. Body length 2.0-2.5mm. from long and narrow part, with 4 small
Body almost entirely heavily pruinose, bristles. Sternite 9 broad, setulose except
black; fore tibia and tarsi black, other tarsi lateral extremes. Indistinct internal vaginal
brown, legs otherwise yellow; antenna yel- sclerotisation present in addition to large,
low to pale brown. Head entirely pruinose, thin-rimmed ringsjoined by abroad sclerite
without shining areas. Interfrontal bristles (spectacles-shaped sclerite of Rohacek
VOLUME 99, NUMBER 3 511
Figs.17-24. Aptilotus zumbadoi. 17, Male terminalia, left lateral. 18, Aedeagus and associated structures,
left lateral. 19, Distiphallus, ventral view. 20, Surstylus, ventral view. 21, Sternite 5 of male. 22, Female ter-
minalia, ventral. 23, Spermathecae and associated sclerites. 24, Female terminalia, dorsal.
1983). Spermathecae spherical, sclerotised 10.ii.l996, ridge top mature oak forest litter,
parts of ducts slightly longer than sperma- R.S. Anderson (1c?,29,GUE); San Jose
thecal bod—y. Province, km. 68 Highway 2, Tres de Junio
Types. Holotype {S, INBio) and 3 Bog, 2600m, 10.ii.l996, litter from forest
paratypes (2c?,l 9,GUE): COSTA RICA: adjacent to Sphagnum bog, R.S. Anderson
Cartago Province, km. 89, Highway 2, Cer- (2(?,GUE); Cerro de la Muerte, 7-
ro de la Muerte, 10.ii.1995, aspirated 13.iv.l985, pan traps, oak cloud forest, L.
among bambo—o litter, S.A. Marshall. Masner and H. Goulet (lc?,GUE); km. 95,
Paratypes. COSTA RICA. Cartago Highway 2, 3200m, 13.iv.l985, oak cloud
Province, 2kmS Villa Mills, 3000m, forest, L. Masner (Ic?, GUE).
512 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
—
Etymology. The specific epithet is a pa- Langstaffdid the illustrations. Paratypes are
tronym in recognition of INBio's Diptera retained in the University of Guelph Insect
speciahst, Manuel Zumbado. Without Man- Collection (CUE).
uel's help we could not have made collec- Literature Cited
tions at the type localities for this and other Marshall, S. A. 1983. A revision of the genus Aptil-
species described here. otus Mik in North America (Diptera; Sphaerocer-
idae). Canadian Journal of Zoology 61: 1910-
Acknowledgments 1924.
Dr. Robert Anderson, Canadian Museum MarshNaolrlt,hS.AmA.eraincdanI. Ps.peScmiietsho1f99A0p.tilAoturse,viewwitohfdteh-e
of Nature, provided specimens, advice con- scriptionsofnew speciesfromNorthAmericaand
cerning high altitude insects of Central Nepal (Diptera; Sphaeroceridae). Canadian Jour-
America, and company in the field. Manuel nal ofZoology 68: 2338-2351.
Zumbado, Instituto Nacional de Biodiver- Rohatcheek,prJe.vi1o9u8s3.geMnounsoLgirmaopshinaandMarcecqluaasrsitfi(cDaitpiotneroa,f
sidad (INBio), Costa Rica, provided invalu- Sphaeroceridae) of Europe. Beitrage zur Ento-
able advice and field support. Rebecca mologie, Berlin 33: 3-195.