Fossil Periscelididae (Diptera)

21 Pages·1993·9.3 MB·

by  David A Grimaldi

PROC. ENTOMOL. SOC. WASH.
95(3), 1993, pp. 383^03
FOSSIL PERISCELIDIDAE (DIPTERA)
David A. Grimaldi and Wayne N. Mathis
(DAG) Department ofEntomology, American Museum ofNatural History, New York,
New York 10024-5192; (WNM) Department of Entomology, NHB 169, Smithsonian
Institution, Washington, D.C. 20560.
Abstract.—AW known fossil species ofperiscelidid flies occur in amber and are treated.
Periscelis annectans Sturtevant, from upper Oligocene amber of Chiapas, Mexico, is
redescribedandillustrated; itbelongstothesubgenusMyodrisLioy. Six newamberspecies
are described, all from the lower Miocene-upper Oligocene amber of the Dominican
Republic. Three species are: Periscelis {Myodris): amberifera, brodzinskyi, andfascianota.
Other species are: Planinasus electra, Stenomicra anacrostichalis and S. sabroskyi. Keys
to some genera and subgenera are presented. Despite their rarity in nature, high diversity
ofperiscelidids in Dominican amber is certainly attributable to an association with de-
caying trees. Presence of modem subgenera in the Oligo-Miocene suggests an origin of
periscelidids perhaps in the Paleocene.
Key Words: Diptera, Periscelididae, Periscelis, Planinasus, Stenomicra, fossil, amber
Flies ofthe family Periscelididae are ob- Amber is a generic term for fossilized,
scure muscomorphans with about 50 de- highly polymerized, resinous sap that can
scribed species worldwide. Specimens are beexuded from alargevarietyofconiferous
rare in collections notably because their and deciduous trees (Langenheim 1969).
habits are often quite specific to tree trunks Although of varying age, pieces date from
and logs that are sometimes in a decaying the Carboniferous (280-345 million years
state(Teskey 1976).PlaninasusCresson, for ago), and those from the Cretaceous (65-
example, is frequently found on rottinglogs 140 million years ago) are the oldest pieces
in or near streams in the neotropics, and with insect inclusions. Because of the fine
Periscelis Loew and Stenomicra Coquillett preservation and three-dimensional detail
usually occur at sap fluxes of living trees preserved in amber, it is an exceptional
(manyneotropicalStenomicraarealsofound mode offossilization for small, delicate in-
in rolled leaves of Heliconia L., living on sects like acalyptrate flies (e.g. Baroni-Ur-
beetle frass). bani and Graeser 1987, Henwood 1992).
Given their predilection for tree trunks The large deposits of Baltic amber (also
and logs, it is not too surprising that an called succinite) have the longest history of
occasional specimen was preserved in am- research on their fossiliferous inclusions
ber. Fivepiecesofamberwithsixspecimens (Bachofen-Echt 1949). These deposits vary
ofperiscelidids represent the total number in age from Eocene to middle Miocene
ofthese flies seen in about 20,000 pieces of (Larsson 1978). Hennig (1965, 1967) re-
Dominican amber screened by the senior vised the diverse fauna of acalyptrates in
author. Specimens, thus, arequiterareeven Balticamber, butnoperiscelididsareknown
as fossils in amber. from that material.
384 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OF WASHINGTON
Sturtevant(1963)describedthefirstfossil prehensive revisions ofthe modem species
periscelidid, Periscelis annectans, from the are first needed. Those now underway are
upperOligocene-lower Miocene amber(ca. as follows: Planinasus (Mathis and Baptis-
25 milUonyearsold)ofChiapasin southern ta).NewWorldPeriscelis(MathisandPapp),
Mexico. The locations and stratigraphy of and New World Stenomicra (Sabrosky and
that amber deposit are well established Grimaldi). The magnitude of the problem
(Hurd et al. 1962, Langenheim et al. 1967). for descriptive taxonomy of these flies is
Amber very similar to that from southern illustratedbyStenomicra: 20 speciesworld-
Mexico is also found in the Dominican Re- wide are described, but about 100 newones
public (Langenheim [1990] prefers to call existfortheneotropicsalone(Sabrosky,pers.
the Mexican and Dominican amber "co- comm.). Itwill be several years beforethese
pal," a term also generallyapplied to amber revisions are complete. That fact plus the
from New Zealand). Like the material from distinctive nature ofthe fossil species com-
Chiapas, Dominican amber also has fine pels us to provide descriptions and new
clarity (and even better preservation ofin- names for the Dominican amber species.
clusions), and both are derived from can- Methods.—Theauthenticityoftheamber
opy-sizedtrees ofthe tropical legumegenus specimens was determined by visual in-
HymenaeaL. (Langenheim 1969, Cunning- spection (e.g. color, clarity, details ofpres-
ham et al. 1983, Hueber and Langenheim ervation), aswell asbyseveral simple, stan-
1986). DominicanamberfromtheCordille- dard tests. Although the exact provenance
ra Central also appears to be contempora- ofthe Dominican amber specimens is un-
neous with the Mexican amber. The stra- known, it can be conservatively estimated
tigraphy, however, isvery incomplete, being tobelowerMiocene-upperOligoceneinage
based solely on benthic Foraminifera from as they match specimens ofknown prove-
the Palo Alto mine (Baroni-Urbani and nance. Cutting, grinding, and polishing of
Saunders 1982)amongthe 15 orsodeposits specimens followed the proceduresgiven in
in this region (Martinez and Schlee 1984). Grimaldi (1993). The Dominican amber
Datingbasedonlithologyhasalsobeendone specimens are deposited in the Entomology
(Brouwer and Brouwer 1982). An Eocene Department, American Museum ofNatural
ageisrepeatedlycitedbyafewinvestigators History. The piece ofChiapas amber is de-
(Poinar and Cannatella 1987, Poinar and posited in the Department ofPaleontology,
Singer 1990). That date is an extrapolation University ofCalifomia, Berkeley, Califor-
fromachemical study(Lambertetal. 1985) nia.
and needs to be confirmed with stratigra- Morphological terminology follows
phy. In the Cordillera Oriental of the Do- McAlpine (1981). In the descriptions, the
minican Republic, there are very recent de- term ipsilateral is used, as in standard med-
posits of fossilized resins that are perhaps ical terminology, to refer to structures on
only several thousand years old. That ma- the same side inbilaterally symmetrical an-
terial is easily identified on the basis ofits imals.
verylightcolor,softness, finesurfacecracks,
and manner ofpreservation ofenclosed in- Family Periscelididae Oldenberg
Periscelidinae Oldenberg, 1914: 41.
sects.
—
We take this opportunity to redescribe Periscelidae. Hendel, 1916: 297 [first use
and illustrate Periscelis annectans and the giving family—status].
five other Dominican fossils. The phylo- Periscelididae. Stackelberg, 1933: 4 [first
use with correct orthography].
genetic position of the fossil species will
hopefully be incorporated into cladistic D'\2i%r\os\s.—Head: Frons with 1-2 fron-
analysesofmodem species. However, com- to-orbitalsetae;postocellarsetaepresentand
VOLUME 95, NUMBER 3 385
divergent or absent. Pedicel cap-like, with Subfamily Periscelidinae Oldenberg
adorsalcleft, bearing 1 ormoredorsoapical Periscelidinae Oldenberg, 1914: 41.
setae; flagellomere 1 frequently sharply de- —
flexed, arising from ventral surface ofped- Diagnosis. //^<3J.' Eye microsetulose
icel; arista pectinate (sometimes bipecti- (bearing interfacetal microsetulae); occiput
nate). Faceuniformlysclerotizedandarched, with a silvery white, microtomentose area
setose laterally. immediately adjacent to posterior margin
Thorax: Dorsocentral setae usually 2 (0 ofcompound eye; frons with only 1 recli-
+ 2), sometimes 1 (0 + 1), none presutural; nate fronto-orbital seta; postocellar setae
posterior intra-alar seta reduced; scutellum present, divergent; ocellarsetae present, well
with 1-2 pairs of marginal setae; scutellar developed; face uniformly sclerotized and
disc bare; 2 notopleural setae; anepistemal transverselyarched (shield-like in Scutops);
seta usually lacking (present in Planinasus). face setose laterally, strongly receded ven-
Wing: subcosta rudimentary, not reaching trally, extended laterally below gena; gena
costal margin norfused apicallywith R, no extended anterodorsally, bearing a row of
;
costal breaks (a weakness in the costa just setae, with anterior seta inserted well above
apicad of the humeral crossvein in Plani- oral margin; mouth opening large.
nasus); costa extended to R4+5 or M; cell Thorax: Postpronotal seta well devel-
dm with a fold running entire length; cell oped.WingwithcostaextendedtoR4+5;cell
cup present, although vein CUA2 either well cupeitherlackingorpresentbutveryweakly
developed or extremely reduced. Mid tibia developed and with vein CuA. extremely
bearing prominent, apicoventral seta. reduced.
Discussion.—Weaccept McAlpine'scon- Abdomen:7th spiracle("stigma")notfree
cept of Periscelididae (1978, 1983, Mathis infemalepostabdomen. SeeGriffiths(1972)
1992), including a few genera that were as- for discussion ofmale terminalia.
signed to Aulacigastridae (CyamopsMelan- Discussion.—The immature stages, and
der, Planinasus Cresson, and Stenomicra to an extent the adults, are associated with
(Coquillett). McAlpine characterized Per- sap from bleedingdeciduous trees(oak, elm,
iscelididaeprimarilybythecap-likepedicel, and Cottonwood). Teskey (1976) described
which has a dorsal cleft. This character oc- and figured a larva ofPeriscelis sp.
curs in all Periscelididae but also in Neu- The genera comprising Periscelidinae are
rochaetidae (McAlpine 1978, Woodley those that Hennig (1969) included in his
1982) and perhaps other genera. Perhaps more restricted concept ofthe family, viz:
these genera should likewise be included in Periscelis Loew, Marbenia Malloch, Neo-
Periscelididae, with the cap-like pedicel as scutops Malloch, Scutops Coquillett, and
a synapomorphy. possibly Diopsosoma Malloch (we doubt-
fully include the latter). Certainly the first
four genera comprise a well-established
Key to Subfamilies of monophyletic assemblage, with corrobora-
Periscelididae tive synapomorphies as follows: 1. Mouth
opening large. 2. Occiput with a silvery
\. Fronto-orbital seta 1; ocellar setae present.
Costashort,extendedtoveinRj CuA,weak white, microtomentose area immediately
,s',
orlacking,cellcupabsent;postpronotumbear- adjacenttotheposteriormarginofthecom-
inga well-developed seta Periscelidinae pound eye. 3. One fronto-orbital seta, rec-
- Fronto-orbitalsetae2;ocellarsetaeabsent.Cos- linate. InthesubfamilyStenomicrinaethere
ta long, extended to vein M; CuA, usuallywell are two fronto-orbital setae, a reclinate and
developed,usuallywithadistinctcellcup(weak
or lacking in Stenomicra); postpronotum lack- proclinate seta. 4. Costal vein short, ex-
inga well-developed seta Stenomicrinae tended only to vein R4+5. The generalized
.
PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OF WASHINGTON
386
condition, foundin relatedgenera and fam- Abdomen:Malegenitalia, seediagnosisof
ilies, is for the costal vein to extend to vein subgenera.
M. 5. Vein CuA, reduced or absent. Typi- Discussion.—All fossil species of Peris-
callythisvein is present, resultingin a well- celis belong to the subgenus Myodris Lioy,
defined cell cup. Its reduction or absence which is distinguished from the other sub-
here is an autapomorphy. 6. Several char- genera by characters indicated in the fol-
acters ofthe male terminalia (see Griffiths lowing key.
1972).
OnlythegenusPeriscelisofthissubfamily Key to Subgenera of Periscelis
has any known fossils, and all are known 1 Prescutellaracrostichal setulae moderatelywell
from amber only. Sturtevant (1963) de- developed,distinctfromotheracrostichalsetu-
scribed the first fossil species, P. annectans, lae; crossvein dm-cu straight and well devel-
from amber taken in the state of Chiapas, opedthroughoutlength; malegenitalialacking
digitiform process at base of epandrium be-
Mexico.Hereweincludeanadditionalthree
tween surstylus and cercus Myodris Lioy
species, all from Dominican amber. - Prescutellar acrostichal setulae undifferentiat-
ed; crossvein dm-cu weakened to completely
Genus Periscelis Loew attenuateanteriorly,usuallyangulateorcurved
toward base, sometimes nearly straight; male
Periscelis Loew, 1858: 113. Type species: genitaliawithaventrallyoriented,narrowpro-
Periscelis annulipes Loew, by subsequent cess at the ventral margin ofthe epandrium
designation(Sturtevant 1923: 1).—Duda, between the surstylusand cerci 2
1934: 5 [revisionpalearcticspecies].—Sa- 2. Mesonotum mostly bare of microtomentum,
shinyandwithbicoloredpatternofdarkbrown
brosky, 1965a:710 [nearctic catalog].—
andyellowishorange;cercusof3bearing5stout,
Pires do Prado, 1975: 1 [neotropical cat- teeth-like setae along anteroventral surface;
alog].-Papp, 1984a: 233-234 [palearctic large species, length 2.7 mm or longer
catalog]; 1988: 273-284 [discussion, fig- Nolioscelis Mathis
- Mesonotum invested with microtomentum,
ures].
appearingsomewhatdull, mostlyunicolorous;
5p/2>TO/7£'rac£'/w Sturtevant, 1923: 1. Type cercus of S bearing several long setulae, es-
species: Sphyroperiscelis wheeleri Sturte- pecially posteriorly, but not teeth-like setae;
— mm
vant, by original designation. Sturte- small species, length 2.5 orsmaller ....
vant, 1954: 551 [synonymy]. Periscelis Loew
Description.—//£'a^.- Face distinctly an-
Subgenus Myodris Lioy
gulate or with a protrudent, transverse ca-
rinainlateralview; dorsal Vi offacenarrow, Myo^mLioy, 1864: 1 103 [asagenus]. Type
notdistinctlyandbroadlyflattenedorshield- species: Notiphila annulata Fallen, by
—
like, ventral halfofface lacking transverse original designation. Mathis, 1992:
furrows. Eye normal, not borne on a con- 1993: 15 [key,asasubgenusofPeriscelis].
spicuousstalk; pedicelcap-like, notporrect. Meronychina Enderlein, 1914: 327 [as age-
Thorax: Scutellum broadly rounded api- nus]. Type species: Notiphila annulata
cally, lacking patch of long setae apically. Fallen, by monotypy.—Enderlein, 1917:
—
Chaetotaxy as follows: posterior dorsocen- 72 [as Meronychia, sic]. Sturtevant,
tral setae 2; presutural seta lacking; prescu- 1954: 556 [synonymy with Periscelis].
tellar acrostichal setae variable, depending Microperiscelis Oldenberg, 1914: 37, 42 [as
on species group; 1 supra-alar seta. WinMg a genus]. Type species: Notiphila annu-
mostly hyaline; apical section of vein lata Fallen, by subsequent designation
straight or very shallowly arched; vein Ri (Sturtevant, 1923:1).-Sturtevant, 1923:
bare above; vein R2+3 more or less evenly 1 [synonymy with Periscelis].
arched throughout length exceptjust before PhorticoidesMalloch, 1915: 86 [asagenus].
apex. Type species: Phorticoidesflinti Malloch,
VOLUME NUMBER
95, 3 387
by original designation.—Sturtevant, sternum to katatergite; katepistemum darker
1954: 556 [synonymy with Periscelis]. than remainderofpleuron
P.facianota. new species
—
Diagnosis. Thorax:Mesonotalvestiture - Acrostichalsetulaefewer,inabout4rows.Api-
variable, essentially bare or densely micro- calscutellarsetaecruciateatapical ^A. Pleuron
tomentose, withthe scutum mostlygraybut uniformly dark colored and lacking a mid-
pleural band P. annectans Sturtevant
with a brown, median stripe on posterior
'/2-%; prescutellar acrostichal setae well de- Periscelis {Myodris) amberifera
veloped. Wing completely hyaline to mac- Grimaldi and Mathis, New Species
ulate; crossvein dm-cu complete and equal- Figs. 1, 2
ly well developed along its length. —
Abdomen: Male genitalia as follows: Description. //^flfl' (Fig. 1): Frons, in-
cluding ocellar triangle, brownish yellow to
epandrium and surstylus connected to in-
yellow; fronto-orbital seta inserted neareye
ternal structures ofgenitalia by membranes
margins; inner and outer vertical setae in-
only; cercus well sclerotized, longer than
sertedclosetogether,distancebetweenabout
wide, becomingnarrowerventrally, bearing
3 times setal width at base; inner vertical
several long setae and 2, stout, tooth-like setaverylong, lengthnearlytwiceouterver-
setae at apex; surstyli usually asymmetrical
tical; ocellar setae inserted just laterad of
to some degree, narrowand acutely pointed
ocellar triangle, long, extended past lunule;
apically, bearing sparse, short setulae; lack-
postocellar setae about equal in length to
inga process between basesofsurstylusand
ocellars, divergent. Antenna: pedicel dark
cercus; gonite distinct and comparatively brown, scape and flagellomere concolor-
1
long, as long or longer than the surstylus.
ous, pale, mostly yellow; pedicel bearing 2
Discussion.—Seven species now com-
large, black, lateral setae and 1 large medial
prise this subgenus, including three that are seta; arista with 7 dorsal and 3 ventral
extant {P. anmdata (Fallen), P. flinti (Mal- branches; no supernumerary lateral trunk
loch),andP. kabuliPapp)andthefourfossil
(asin speciesofPlaninasus). Faceobscured.
species that are keyed and described in this Genal setulae dense, long.
paper. Thorax: Mesonotum, pleuron, and post-
notum uniformly dark brown. Acrostichal
Key to Fossil Species of the setulae irregularly arranged, not in rows;
Subgenus Myodris katepistemum bearing 1 largeand 1 smaller
1. Thorax appearing densely microtomentose, setae; distance between ipsilateral dorso-
mostly pale gray with some brown spots; fore central setae about V2 length ofeither seta;
femur with 3 prominent setae along apical 'A distance between dorsocentral rows wide,
ofposteroventralsurface;tibiaeuniformlycol- about equal to length of a seta; a pair of
ored P. brodzi)iskyi, new species
- Thorax appearing uniformly dark brown and prescutellar acrostichal setae between pos-
lackingdensemicrotomentum;forefemurwith teriordorsocentrals, length and thickness '/3
5-6 prominent setae along apical 'A of pos- that ofposterior dorsocentral seta, distance
teroventralsurface;tibiaewithalternatingdark from posterior dorsocentral about equal to
and pale bands 2 lengthofsmallerseta; scutellumwith2 pairs
2. Fronsincludingocellartriangleuniformlypale
brown; face lackingdark spot in middle .... ofsetae; apical pair twice length ofanterior
P. amberifera. new species pair. Halterpale. Wing(Fig. 2)with uniform
- Atleastocellartriangledarkbrown,contrasted light infuscation on apical %; vein R, long,
with paler remainder offrons; face with dark extendedtonearlymidwayalongcostalvein;
bigeminate spot in middle 3 vein R2+3 arched; veins R4+5 and M, par-
3. Arecgruolsatricrhoawls.setAupliacealnusmceurtoelulsa,r isnetaaebousttro6ngilry- allel; vein M, endedjust short ofwing mar-
cruciatebeforemidlengthofsetae. Pleuronwith gin; cell dm large, wider than distance be-
amidpleuraldarkband,extended fromanepi- tween veins R4+5 and M,. Legs: fore femur
388 PROCEEDINGS OFTHE ENTOMOLOGICAL SOCIETY OF WASHINGTON
i 'f
Figs. 1, 2. Periscelisambehfera. 1, head, posterodorsal view; 2, wing.
dark brown, with row of 8-9 setae along 8-207A): the specific provenance is un-
posterior surface, lengths slightly greater known within the Dominican Republic; the
than femoral width; apical '/j ofall femora inclusion is in a large piece of amber (4.0
pale;tibiaewith2darkbands,%and%along X 3.3 cm) that is dark yellow and has sev-
length oftibia; tarsomeres pale, except pre- eral small inclusions, including a male ant
tarsus, which is dark; basitarsomere about and a mymarid wasp.
equal in length to all other tarsomeres. Etymology.—The speciesepithet, amber-
Abdomen:Dorsoventrallysomewhat flat- ifera, refers to the holotype being an inclu-
tened, sides tapered apically. Tergites pale sion borne in amber.
brown. Remarks.—Thisspeciesisverysimilarto
Measurements.—Head width and thorax P. facianota but is distinguished from the
length not measurable; body length 2.63 latter by the coloration ofthe frons, includ-
mm, wing length 1.76 mm. ing the ocellar triangle, which is generally
Typematerial.—Holotype2(AMNH DR- pale brownish yellow to yellow.
VOLUME NUMBER
95. 3 389
Periscelis {Myodris)facianota ron isobscured. Acrostichalsetulaearranged
Grimaldi and Mathis, New Species in about 6 irregular rows between anterior
Figs. 3-5 dorsocentrals; posterior dorsocentral setae
about twice the length and thickness ofthe
Description.—//^(3<^ (Figs. 3, 4): Frons
mostly pale, brownish yellow, except for anterior dorsocentral setae, slightly curved,
dark brown ocellar triangle and broad area convergent; lateral thoracic setae all quite
immediately adjacent. All setae black. thick, curved, andstiff; 1 stout postpronotal
Fronto-orbital setae inserted about midway seta; postalarsetacurvedposterodorsadand
alonglength offrons, very close to eye mar- adpressed to notum; 2 large katepistemal
gin, lengthaboutsameasoutervertical seta; setae. Anterior scutellar setae convergent,
lying close along sides of scutellum; apical
innervertical seta slightly longerthan outer
scutellars twice the length of anterior scu-
seta, with slightly curved tips; distance be-
tellarsetae, crossed forabout%theirlength,
tween inner and outer vertical setae about
4-5 times diameter ofsetal bases (best seen slightly upright. Wing (Fig. 5): slightly in-
fuscate but without markings; veins R2+3,
indorsal view); ocellarsetae inserted slight- R4+5, and M parallel; vein CuA, incom-
ly outside triangle, lateral to sides joining plete. Halter pale. Legs: femora slightly
anteriorand posteriorocelli; postocellarseta brown; fore femur with row of about 10
with acute bend at base, strongly divergent, stout setae on ventral surface; tibiae with 2
lying immediately behind posterior ocelli. dark bands, forming yellow apical, middle,
Posterodorsal marginoffronsformingacute and proximal bands; tarsomeres and 2
1
angle with posterior surface of head, this pale brown, remainder paler.
edge quite sharp; posterior surface ofhead Abdomen: Tergites dark brown.
dark brown, slightly concave. Antenna: Measurements.—Head width 1.02 mm;
pedicel velvety black, strikingly contrasted thorax length 1.26 mm; body length 2.913
withremainderofyellowantennaandfrons, mm; distance between apices R.-R.+j 1.04
bearing3 stoutdorsolateral setaeand 1 ven- mm; distance between apices R2+3-R4+5
trolateral seta(somedorsolateralswithapex 0.12 mm;lengthalongbasalsegmentofvein
slightly curved), 1 largedorsal seta and sev- M/apical segment 0.29/0.91 mm.
eral smaller proximal ones dorsolateral to Type material.—Holotype 9 (AMNH
it; flagellomere 1 yellow; arista with 6 dor- 11856): the specific provenance is unknown
sal, 3 ventral branches, plus small terminal within the Dominican Republic; the inclu-
fork and about 8 minute medial branches sion is in a small piece ofamber (0.7 x 1.3
[apices of arista inadvertently sheared off cm; 1.1 X 1.3 cm before cutting) that is
during a later preparation]. Face slightly medium yellow and has two layers of fine
carinate, with bigeminate black spots in bubbles and no other insect inclusions.
middle offace between narrowest area sep- Etymology.—The specific epithet, ^c/'a-
arating eye margins. Gena bearing 3 setae nota, is of Latin derivation and alludes to
above frontal-genal suture, pointed ventro- the brown, bigeminate spot on the face.
laterally; row of6 setae below suture. Clyp- Remarks.—Although similar to P. am-
eus and palp black; clypeus with pointed beriferaandP. annectans, thisspeciesisdis-
frontal surface. tinguished as follows: (1) the dark brown
Thorax (Fig. 3): Mesonotum uniformly ocellar triangle that is distinctly contrasted
dark brown. Pleuron mostly pale, with a with the mostly yellow remainder of the
midpleural dark band, extended from an- frons.(2)thesixirregularrowsofacrostichal
epistemum to katatergite; at least katepi- setulae, and (3) apical scutellar setae that
stemum apparentlydark, but much ofpleu- are strongly cruciate near their bases.
390 PROCEEDINGS OFTHE ENTOMOLOGICAL SOCIETY OFWASHINGTON
Figs. 3-5. Periscelisfacianota. 3, head and thorax, dorsal view. 4, head, anteriorview. 5, wing.
VOLUME NUMBER
95, 3 391
Periscelis (Myodris) brodzinskyi surface, length nearly twice width oftibia.
Grimaldi and Mathis, New Species Leftwingadpressedtoabdomen; rightwing
Fig. 6 mostly visible; humeral vein present; sub-
Description.—This specimen is obscured costal vein short, length less than Vi length
by an ant that is on top of the specimen. ofcell sc and not sharply upturned toward
The ant's mandibles are apparently biting costal vein; vein R, long, nearly Vi length of
intothe fly'sscutellum. The flyis intact, but wing; vein R4+5 straight, equidistant be-
the wings are not fully visible. The left wing tween R2+3 and M,; veins R2+3 and Mj
is folded on top of the abdomen, and the slightly sinuous, with apices slightly diver-
right wing is partially hidden. gent; pale subapical band of infuscation
Head: Frons mostly pale yellow, fronto- present; veins CuA, and M, convergent at
orbital plates slightlydarker. Fronto-orbital crossvein m-cu; basal cells of wings ob-
seta inserted about midway along length of scured.
frons. Inner and outer vertical setae ob- Abdomen:Mostofabdomenandgenitalia
scured; ocellar setae inserted within ocellar obscured.
triangle, reclinate, length obscured. Anten- Measurements.—Head not measurable;
na: scape and pedicel yellowish, scape body length 3.65 mm; thorax length 1.37
slightly darker and bearing larger seta on mm; wing length 2.20 mm; distance be-
medial surface, 1 on anterolateral surface, tween apices R.-R.+j 1.10 mm; distance
3smalleronesonventrolateralmargin;aris- between apices R2+3-R4+5 0.124 mm; length
ta plumose, with 5 dorsal and 3 ventral alongbasalportionofveinM/apicalportion
branches (and very small terminal fork). 0.34/0.93 mm.
Face obscured, but setae can be seen in lat- Type material.—Holotype(sex?; AMNH
eral view: rowof4-5 oriented mediad; with DR-8-207B): the specific provenance is un-
3 setaeventrolateraltothese, orientedlater- known within the Dominican Republic; the
ad. Lateraloral marginwith 5-6 setae. Gena inclusion is a large piece of amber (4.0 x
withseveralsmallsetulae,butnolargerseta. 3.3 cm) that is dark yellow and has several
Eye pale. small inclusions, including a male ant and
Thorax:Notumpartiallyobscuredbyant, a mymarid wasp.
but apparently pale, yellowish gray with Etymology.—It is a pleasure to name this
some light brown areas. Postpronotum genitive patronym after Mr. Jacob Brodzin-
bearinga smallersetaanteriorly in addition sky, whose enthusiasm for fossils in amber
to larger seta; posterior notopleural seta and entrepreneurial skills made the amber
slightly smaller; anterior dorsocentral seta pieces we studied from the Dominican Re-
short, length about Vi that ofposterior seta; public available to our study.
1 large katepistemal seta (oriented dorsad) Remarks.—This species differs markedly
and several smaller ones; a pair oflong api- from the precedingtwo species and iseasily
cal scutellarsetaepresent, tipsnearlytouch- distinguished by the: (1) densely microto-
ing, length slightly greater than posterior mentose mesonotum thatismostlypalegray
dorsocentrals; anterior scutellar setae ob- with some brown spots (the mesonotum in
scured. Legs: fore and mid femora pale the preceding species is entirely black, with
brown, other segments and hind legs paler; at most sparse microtomentum); (2) fore fe-
tibiae uniformly colored, lackingbands; fore murbearing 3 prominent setae along apical
femur with row of 3 larger setae on apical halfofposteroventral surface (there are 5-
half of ventral surface; tarsomere 1 about 6 setae in the other species); (3) tibiae uni-
equal in length to tarsomeres 2 + 3 + 4; formly colored (the tibiae in the other fossil
mid tibia with large apical spine on medial species are distinctly banded.
PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OF WASHINGTON
392
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v.
Fig. 6. Periscelisbrodzinskyi(with ant bitinginto thorax), dorsolateral view.