Primitive new ants in Cretaceous amber from Myanmar, New Jersey, and Canada (Hymenoptera, Formicidae)

2005·3.1 MB·English

by  Engel, Michael S

AMERICAN MUSEUM
Novitates
PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY
CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024
Number 3485, 23 pp., 11 figures, 5 tables July 25, 2005
Primitive New Ants in Cretaceous Amber from
Myanmar, New Jersey, and Canada
(Hymenoptera: Formicidae)
MICHAEL S. ENGEL! AND DAVID A. GRIMALDI?
CONTENTS
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' Division of Invertebrate Zoology, American Museum of Natural History; Division of Entomology, Natural History
Museum, and Department of Ecology and Evolutionary Biology, Snow Hall, 1460 Jayhawk Boulevard, University
of Kansas, Lawrence, Kansas 66045—7523 ([email protected]).
? Division of Invertebrate Zoology (Entomology), American Museum of Natural History ([email protected]).
Copyright © American Museum of Natural History 2005 ISSN 0003-0082
AMERICAN MUSEUM NOVITATES NO. 3485
ABSTRACT
New information is provided on the oldest fossil ants (Formicidae), including the description
of a new species of +Sphecomyrma (+Sphecomyrminae), a new genus of sphecomyrmines, a
new genus of apparent myrmeciines, and a new genus of apparent aneuretines. New material
from New Jersey amber (Turonian) includes workers of *Sphecomyrma freyi Wilson and
Brown preserved together in the same piece of amber, a worker of an unidentifiable *Sphe-
comyrma species, and a worker of tBrownimecia clavata Grimaldi, Agosti, and Carpenter
(*Brownimeciinae). A new species of +Sphecomyrma in New Jersey amber is described and
figured from a worker as 7S. mesaki, new species. Two worker specimens in Campanian amber
from Canada are described, one of which is described as +tCananeuretus occidentalis, new
genus and species, and is tentatively placed in Aneuretinae. From Burmese amber (Albian-
Cenomanian) are the oldest, definitive ants, along with ones in amber from Charente-Maritime
of France (approximately contemporaneous in age). A new genus and species, allied to +Sphe-
comyrma, is described from these deposits as +Sphecomyrmodes orientalis, along with a
remarkable new “‘poneroid’”’, }{Myanmyrma gracilis, new genus and species (Myrmeciinae?).
A key to the species of +Sphecomyrma is provided, the classification of ants summarized, and
the Cretaceous records of Formicidae briefly outlined.
INTRODUCTION myrma freyi Wilson and Brown, in New Jer-
sey amber. Since 1985, ants have been re-
Ants can truly be said to shape the terres-
ported in Cretaceous amber from Siberia,
trial world. Of the 11,833 species of Formi-
France, Canada, Burma, and additional new
cidae*, many have a profound impact on nat-
specimens and taxa in New Jersey amber (re-
ural and manmade ecosystems, which is
viewed in Grimaldi et al., 1997, with addi-
made possible by their eusociality, frequently
tions by Dlussky, 1999; Grimaldi and Agosti,
large colony sizes, and abundance. There is
2000a; Grimaldi et al., 2002; Nel et al., 2004:
scarcely a place outside of the polar regions
vide appendix 1). Here we report important
where one cannot find these insects or their
new specimens of described ant taxa recently
effects. Ants are among the most common
discovered in New Jersey amber, new species
and diverse kind of insect in various Ceno-
of +sphecomyrmines in both New Jersey and
zoic deposits, and are particularly well
Burmese amber, as well as three new genera
known in the fossilized faunas of Dominican,
in Burmese and Canadian ambers (e.g., figs.
Sicilian, and Baltic ambers (Rasnitsyn and
1—3). While it is well established that New
Kulicka, 1990; Skalski and Veggiani, 1990;
Jersey amber is of Turonian age (Grimaldi et
Wilson, 1985a), as are the less spectacularly
preserved compressions from Lagerstatte al., 2000) and that Canadian amber is Cam-
panian (Borkent, 1995), the dating of Bur-
such as Florissant (Carpenter, 1930), Green
River (Dlussky and Rasnitsyn, 2003), and mese amber has been contentious. Formerly
other Tertiary localities throughout the believed to be of Tertiary age, recent work
world. Although Formicidae came into their has demonstrated that the Burmese deposit
own during the Cenozoic, in the Mesozoic dates from the mid-Cretaceous (e.g., Zheri-
and Early Tertiary (Paleocene) formicids khin and Ross, 2000; Grimaldi et al., 2002;
were rare, and their earliest evolution has Cruickshank and Ko, 2003). Thus, those taxa
been gradually unveiled with each new fossil in Burmese amber (Albian-Cenomanian) are
discovery (e.g., Wilson et al., 1967; Wilson, among the current oldest records of ants
1985b; Grimaldi et al., 1997; Grimaldi and along with ants in amber of approximately
Agosti, 2000a; Dlussky and Rasnitsyn, 2003; contemporaneous age from Charente-Mari-
Dlussky et al., 2004; Nel et al., 2004). time, France (Nel et al., 2004), being at least
Until 1985, the only true formicid known 8—10 million years older than previous re-
from the Cretaceous Period was }tSpheco- cords of the family.
In keeping with myrmecological tradition
and literature, we generally use terminology
3 Species total accurate as of 17 June 2005 (vide
www.antbase.org). for morphological structures (e.g., antennal
2005 ENGEL AND GRIMALDI: CRETACEOUS ANTS 5
Figs. 1-3. Three Cretaceous amber ants. 1. (Myanmyrma gracilis, new genus and species (AMNH
Bu-014) in Burmese amber. 2. }Cananeuretus occidentalis, new genus and species (TMP 8.89.7) in
Canadian amber. 3. }Sphecomyrmodes orientalis, new genus and species (AMNH Bu-351) in Burmese
amber.
parts) as outlined by Ho6lldobler and Wilson classification, herein, noting in various places
(1990) and Bolton (1994); however, for body where we believe it might eventually be
regions we have used head, mesosoma (= modified. Material considered herein is de-
alitrunk), and metasoma (= petiole + gaster), posited in the Amber Collection, Division of
as is standard in apocritan Hymenoptera. Invertebrate Zoology, American Museum of
Throughout, “‘head length” is measured from Natural History, New York (AMNH); the
the apex of the vertex to the anterior border Department of Palaeontology of the Natural
of the clypeus. The higher classification of History Museum, London (NHML); and
the ants has recently undergone a major re- Royal Tyrell Museum of Palaeontology,
arrangement owing to the work of Bolton Drumheller, Canada (TMP). Specimens in
(2003) (summarized with minor modifica- the AMNH collection were embedded in ep-
tions in table 1). We have employed that oxy for preparation and study, using the pro-
AMERICAN MUSEUM NOVITATES NO. 3485
TABLE 1
Hierarchical Suprageneric Classification of the Ants (Formicidae) and Antlike Wasps (Armaniidae)
(modified from Bolton, 2003)"
Family ;ARMANIIDAE Dlussky
Family FORMICIDAE Latreille
Subfamily +Sphecomyrminae Wilson & Brown myrmicomorph group, Subfamily Myrmicinae (continued)
Tribe +Sphecomyrmini Wilson & Brown dacetite tribal group
Tribe +Haidomyrmecini Bolton Tribe Basicerotini Brown
“poneromorph” group [paraphyletic] Tribe Dacetini Forel¢
Subfamily +Brownimeciinae Bolton Tribe Phalacromyrmecini Dlussky & Fedoseeva
Subfamily Amblyoponinae Forel> cataulacite tribal group
Subfamily Paraponerinae Emery Tribe Cataulacini Emery
Subfamily Heteroponerinae Bolton Tribe Cephalotini Smith
Subfamily Ponerinae Lepeletier de Saint Fargeau attite tribal group
Tribe Ponerini Lepeletier de Saint Fargeau Tribe Blepharidattini Wheeler & Wheeler
Tribe Thaumatomyrmecini Emery Tribe Attini Smith
Tribe Platythyreini Emery solenopsidite tribal group
Subfamily Proceratiinae Emery Tribe Stenammini Ashmead
Tribe Proceratiini Emery Tribe Solenopsidini Forel
Tribe Probolomyrmecini Perrault myrmicite tribal group
Subfamily Ectatomminae Emery Tribe Myrmicini Lepeletier de Saint Fargeau
Tribe Ectatommini Emery Tribe Tetramoriini Emery
Tribe Typhlomyrmecini Emery Tribe Pheidolini Emery
leptanillomorph group Tribe Lenomyrmecini Bolton
Subfamily Leptanillinae Emery Tribe Paratopulini Wheeler
Tribe Anomalomyrmini Taylor formicoxenite tribal group
Tribe Leptanillini Emery Tribe Crematogastrini Forel
dorylomorph group Tribe Ankylomyrmini Bolton
Subfamily Cerapachyinae Forel Tribe Liomyrmecini Mayr
Tribe Acanthostichini Emery Tribe Meranoplini Emery
Tribe Cylindromyrmecini Emery Tribe Myrmicariini Forel
Tribe Cerapachyini Forel Tribe Formicoxenini Forel
Subfamily Leptanilloidinae Bolton formicomorph group
Subfamily Aenictinae Emery Subfamily +Formiciinae Lutz
Subfamily Aenictogitoninae Ashmead Subfamily Formicinae Latreille
Subfamily Ecitoninae Forel Tribe Dimorphomyrmecini Emery4
Tribe Cheliomyrmecini Wheeler Tribe Myrmecorhynchini Wheeler
Tribe Ecitonini Forel plagiolepidite tribal group
Subfamily Dorylinae Leach Tribe Lasiini Ashmead
myrmeciomorph group Tribe Plagiolepidini Forel
Subfamily Myrmeciinae Emery Tribe Myrmoteratini Emery
Tribe Myrmeciini Emery formicite tribal group
Tribe Prionomyrmecini Wheeler Tribe Oecophyllini Emery
Subfamily Pseudomyrmecinae Smith Tribe Gigantiopini Ashmead
myrmicomorph group Tribe Camponotini Forel*
Subfamily Agroecomyrmecinae Carpenter Tribe Notostigmatini Bolton
Subfamily Myrmicinae Lepeletier de Saint Fargeau Tribe Formicini Latreille
Tribe Stegomyrmecini Wheeler Tribe Melophorini Forel
Tribe Myrmecinini Ashmead Subfamily Aneuretinae Emery
Tribe Metaponini Forel Subfamily Dolichoderinae Forel
Tribe Melissotarsini Emery
4Bolton’s (2003) informal groups of subfamilies as well as informal tribal groups are employed herein. As continued phylogenetic work
refines the higher classification of the Myrmicinae and Formicinae, these tribal groups may warrant formalization as supertribes. If so,
then we recommend that the suffix -iti be employed for the supertribal rank as has been done for other aculeate lineages (e.g., Engel, 2005).
In advance of this, we have used informal names for these tribal groups based on this suffix as to avoid confusion when referring infor-
mally to a particular tribe (i.e., to avoid confusion caused by, for example, using “‘attine” for members of the attine tribal group [which
might also include Blepharidatta} or for actual members of the Attini).
>The subfamily Apomyrminae Dlussky and Fedoseeva (formerly in the leptanillomorph group, sensu Bolton, 2003) is herein considered
a synonym of Amblyoponinae as proposed by Saux et al. (2004).
© In Grimaldi and Engel (2005) this name appeared as “Dacetonini” based on a misinterpretation of the Greek root on the part of MSE.
The name is taken from the Greek word daketon, meaning “biting animal”. MSE erroneously believed the word to terminate in Greek as
daKketwyv which would result in an augmented stem and require the retention of the terminal “-on” in the family-group name (apparently
Forel, 1892, himself, believed this as well since he originally proposed the name as “‘Dacetonini”, and innumerable myrmecologists also
used this form, alongside the form “Dacetini’”, until recently). However, the original Greek terminates with omicron (rather than omega),
i.e., daxeTtov, which necessitates the dropping of the “-on” and leaving the combining stem as “dacet-”. Hence the family-group name is
correctly spelled as Dacetini (in this case with the tribal suffix). The name appears here in its correct form and will so in future editions of
Grimaldi and Engel (2005)
4Bolton (2003) used the junior name Gesomyrmecini since the type genus of Dimorphomyrmecini (i.e., Dimorphomyrmex) is a syn-
onym of Gesomyrmex. However, ICZN (1999: Art. 40.1) states that a family-group name cannot be rejected even if its type genus is con-
sidered a junior synonym of another genus. Since Dimorphomyrmecini dates from Emery (1895: as Dimorphomyrmii) and Gesomyrmeci-
ni from Ashmead (1905: as Gesomyrmicinae), the former name should be employed for the tribe.
¢The subfamily +Palaeosminthurinae has recently been synonymized with Camponotini (Snelling, in press).
2005 ENGEL AND GRIMALDI: CRETACEOUS ANTS sy,
cedure outlined by Nascimbene and Silver- (perhaps paraphyletic?) to Formicidae (vide
stein (2000). table 1 and appendix 1).
It is interesting to note that many primitive
SYSTEMATIC PALEONTOLOGY ants have clypeal spicules with rounded api-
ces (e.g., fSphecomyrmodes, *Myanmyrma;
FAMILY FORMICIDAE LATREILLE
Amblyoponinae). Apomyrma has similar
DIAGNOsIs: Head prognathous; dorsal rim spicules, but these are located on the labrum
of torulus often tuberculate or concealed un- rather than along the anterior clypeal margin.
der vertical lamella of frons; antenna genic- The significance of this trait is as of yet un-
ulate. Primitively with anterior margin of clear (e.g., a ground-plan feature with nu-
clypeus spiculate (apomorphically lost in merous, apomorphic losses; or functional
many modern lineages: vide infra). Infrabuc- convergence).
cal sac present between labium and hypo-
pharynx. Pronotum with posterodorsal mar- SUBFAMILY +SPHECOMYRMINAE
gin weakly concave; posterolateral apex trun- WILSON AND BROWN
cate anterior to tegula. Metapleural gland
+Sphecomyrmodes, new genus
present in females, opening above metacoxa
(rarely absent); meso- and metacoxae contig- TYPE SPECIES: |Sphecomyrmodes oriental-
uous; inner metatibial spur modified as cal- is, new species.
car. Hind wing typically without jugal lobe DIAGNOsIs: Distinguished from all other
(presence of the lobe is plesiomorphic within species of the tribe Sphecomyrmini by the
the family and likely part of the familial minute, peglike denticles running along the
ground plan). Metasoma petiolate; first me- entirety of the anterior margin of the clypeus
tasomal segment forming true node (strongly and from *Sphecomyrma by the absence of
constricted anteriorly and posteriorly); first a medial extension or process on the clypeal
metasomal sternum separated from second margin.
metasomal sternum by deep constriction. ETyMOoLoGy: The new genus-group name
Morphologically distinct, sterile worker caste is a combination of }Sphecomyrma, type ge-
typically present* (i.e., advanced eusocial); nus of the subfamily, and the suffix—odes,
reproductives typically macropterous, work- meaning “‘with the form of’’. The name is
ers apterous. Workers with pronotum fused masculine.
to mesothorax (a freely articulating prono-
tum, present in some species, is_ plesio- +Sphecomyrmodes orientalis, new species
morphic and undoubtedly part of the formi- Figures 3—4
cid ground plan), remaining segments typi-
cally fused. Species advanced eusocial. DtAGNosIs: As for the genus (vide supra).
COMMENTs: The ants, currently including DESCRIPTION: Head. Relatively large,
11,833 species (Bolton, 1995; www. height of head slightly less than length of
antbase.org) have a cosmopolitan distribution alitrunk. Length of head 1.23 mm (with man-
and are among the most recognizable of all dibles closed). No apparent microsculpture
insects. Numerous species exist in Cenozoic on cuticle of head. Clypeus setose; setae of
deposits around the world and are relatively moderate length and widely separated. Man-
commonly encountered. Species of Creta- dible simple, with only two teeth; outer sur-
ceous formicids, which are very rare, are face with numerous, widely scattered, fine
briefly outlined in appendix 1. setae. Antenna of moderate length, with
Bolton (2003) considered the antlike scape short, funicular article I (pedicel)
wasps of the Cretaceous family Armaniidae shortest antennal article, funicular article II
to represent the basalmost subfamily of the the longest article of funiculus. Lengths of
ants. We have, however, retained armaniids antennal articles (in mm): scape 0.23, pedicel
at the family rank and as the sister group (funicular article [fa] I) 0.13, fall 0.32, fallIlI
O.N5;- fal «OOS, fav *O.15;. fav -0.1353faVvil
0.17, faVIII 0.17, falX 0.17, faX 0.17, faxXI
4 Some inquilines have apomorphically lost the work-
er caste. 0.27. Mesosoma. Mesosomal length 1.33
6 AMERICAN MUSEUM NOVITATES NO. 3485
clypeus
flagellomere 1
Fig. 4. Holotype worker of }Sphecomyrmodes orientalis, new genus and species (AMNH Bu-351);
general habitus, sting, clypeal margin and mandibles, and antenna.
mm; without apparent microsculpturing, with ly curved inward at their extreme apices (vis-
scattered fine, short setae on all visible sur- ible on left foreleg). Pairs of stiff setae on
faces, those on propodeum about twice as ventral surface of protarsomeres: tarsomeres
long as other setae. Coxae large, slightly in- I-III with three pairs, [TV with two small
flated, ventrally setose, setae numerous and pairs. Pretarsal claw with minute subapical
fine. Legs moderate length. Foreleg with tar- tooth. Metasoma. Attachment of petiole to
somere I distinctly longer than combined propodeum not particularly thick; thickness
lengths of more distal tarsomeres; tarsomere (measured in lateral view) of anterior end of
I with “‘antennal cleaner” (strigil) a velvety petiolar peduncle 0.3X greatest depth of pro-
notch on ventral margin of proximal end; cal- podeum. Petiole length 0.38 mm, height 0.37
car present, length slightly longer than great- mm. Preserved portion of gaster 1.73 mm in
est width of profemur, ventral margin with length. Integument without apparent micros-
row of fine teeth and (apically) setae. Patch culpturing, with scattered, fine setae. Distal-
of dense, elongate setae opposite strigil on most metasomal segments torn apart, al-
profemur; inner posterior surface of protibial though sting bulb and sting well preserved
apex with three stout, spinelike setae minute- beneath metasoma (fig. 4).
2005 ENGEL AND GRIMALDI: CRETACEOUS ANTS 7
TYPE MATERIAL: Holotype. AMNH Bu- +Sphecomyrma mesaki, new species
351, an incompletely preserved worker in a Figure 5
piece of reddish-orange amber, from Myan-
mar. Collected in Kachin state, Tanai village, DIAGNOsIs: Distinguished from all other
on Ledo Road, 105 km NW Myitkyna, via species of the genus by the median portion
Leeward Capital Corp., 1999. of the clypeus having a long ventral lobe,
ETYMOLoGy: The specific epithet is the length of the clypeus through the lobe is
Latin word orientalis, meaning ‘‘of the east”’ 0.46 the greatest width of clypeus; clypeus
setose; and scape very short (1.2 the length
and is a reference to this being the first spe-
of longest funicular article). The species can
cies of the tribe +Sphecomyrmini (sensu Bol-
ton, 2003) recorded from Myanmar. be further distinguished from 7S. freyi (the
other species of the genus in New Jersey am-
ber) by broad, shallow scrobes at base of an-
Genus *Sphecomyrma Wilson and Brown
tennae; an eye that is approximately 1/3 larg-
+Sphecomyrma Wilson and Brown, Jn Wilson et er and oval (vs. almost perfectly round in 7S.
al., 1967: 8. Type species: }Sphecomyrma freyi freyi); and a large head CUength of head/
Wilson and Brown, 1967, monobasic and orig- length of mesosoma = 0.83, vs. 0.65 in 7S.
inal designation. freyi).
DESCRIPTION: Petiole and gaster not pre-
DIAGNOsIS: Scape short; funiculus long
served, so only head, mesosoma, and legs
and filiform, about four times length of
preserved. Head. Large, length of head
scape; promesothoracic suture complete and
slightly less than length of alitrunk. Length
well developed; trochantellus absent; petiole
of head 2.20 mm (with mandibles closed);
with distinct, domed node widely separated
width of head 1.95 mm; length of eye 0.66
from propodeum and remainder of metasoma
mm. No microsculpture on cuticle of head.
by deep constrictions; cuticle without sculp-
Vertex with fine, sparse pilosity, setae ca. 0.2
turing, superficial microscopic relief, with
mm long. Ocelli present, median ocellus sit-
scattered and sparse setae.
uated just above dorsal tangent of compound
COMMENTS: The genus, which is defined
eyes. Face bare. Bases of antennae situated
largely by plesiomorphies, is doubtfully
in shallow, broad scrobes; length of scrobe
monophyletic. It contains three species:
about equal to length of scape and articulat-
+Sphecomyrma canadensis Wilson in Cana-
ing base. Eyes well developed, bare, situated
dian amber, and +S. freyi Wilson and Brown
well above bases of antennae; gena deep.
and a new species in New Jersey amber (vide
Lateral portions of clypeus quadrate; median
infra). In addition, we provide information
portion distended into long ventral lobe that
from newly identified material of +S. freyi.
extends to ventral margin of closed right
mandible. Clypeus setose, except on middle
Key to Species of }Sphecomyrma
part. Mandibles simple, with only two teeth.
(based on the worker caste)
Antennae of moderate length, with scape
short, funicular article I (pedicel) shortest an-
1. Anterior margin of clypeus with short, broad
extension, surface with two, long setae at tennal article, funicular article II the longest
most; compound eye round .......... 2 article of funiculus. Lengths of antennal ar-
— Anterior margin of clypeus with long, medial ticles Gn mm): scape 0.53, pedicel (funicular
lobe (fig. 5), surface with numerous, long article [fa] I) 0.20, fall 0.43, falII 0.35, falV
setae; compound eye oval [New Jersey am- 0.30, faV 0.23, faVI 0.23, faVII 0.30, faVIII
Lisi GAL aa eae Ree en he ee 0.22, falX 0.26, faX 0.30, faXI 0.33. Meso-
.... S. mesaki Engel and Grimaldi, n.sp.
soma. Mesosomal length 2.66 mm; without
2. Third antennal article slightly more than
microsculpturing, except at posterolateral
twice as long as second article [New Jersey
margin of promesonotal suture, where eight
AUD OTT. sok tea d oa © connie Le clerel aiee fore eeo ate Lkd ae?
fine grooves occur. Dome of promesonotum
Wo Fs cha ee +S. freyi Wilson and Brown
— Third antennal article about as long as second setose; several fine setae on dorsal surface of
article [Canadian amber] ............. metanotum and propodeum. Coxae large, in-
Serkan el as ENE +S. canadensis Wilson flated, ventrally setose. Attachment of petiole
8 AMERICAN MUSEUM NOVITATES NO. 3485
metapleural propodeum
gland opening
—ed@
scape
pedicel
clypeus \
mandible |! oe
Fig. 5. Holotype worker of +Sphecomyrma mesaki, new species (AMNH NJ-1023); lateral habitus
and facial view.
2005 ENGEL AND GRIMALDI: CRETACEOUS ANTS 9
to propodeum not particularly thick; thick- bedded and trimmed to 14 X 15 X 4 mm.
ness (measured in lateral view) of anterior The piece contains two workers of 7S. freyi.
end of petiolar peduncle 0.3x greatest depth DESCRIPTIVE NOTES: Both workers are
of propodeum. Metapleural gland opening largely but not completely preserved. Spec-
(MGO) and MG bulla obvious, situated on imen A has the frontal half of the head miss-
posterolateral part of propodeum just above ing; most of the antenna is present except for
metacoxa. MGO small, with groove running bases of the scapes; the entirety of the re-
between it and extended almost to vental mainder of the body is preserved and the
margin of propodeum. Legs moderate length. sting appears largely or fully extruded. Spec-
Foreleg with tarsomere I slightly longer than imen B has the dorsal and apical part of the
combined length of more distal tarsomeres; gaster missing, as well as portions of the
tarsomere I with “antennal cleaner”’ (strigil) right hind leg; the anterior third of the head
a velvety notch on ventral margin of proxi- is obscured by Schimmel and a bubble.
mal end; calcar present, length slightly lon- Measurements of body: Width of head
ger than greatest width of femur, ventral mar- (specimen B), 1.03 mm; length of head (B,
gin with row of fine teeth and (apically) approximate), 1.20 mm; length of mesosoma
hairs. Stiff setae on ventral surface of pro- 1.39 mm (B), 1. 40 mm (A); length of petiole
tarsomeres: tarsomere I with 7 pairs, II with 0.29 mm (B), 0.33 mm (A); length of gaster
3 pairs, HI with 3 small pairs, [IV with 2 (A) 1.72 mm; length of extruded portion of
small pairs. Pretarsal claw with subapical sting (A), 0.33 mm. Measurements of anten-
tooth. Metasoma not preserved. nal articles (as measured for right antenna in
TYPE MATERIAL: Holotype. AMNH NJ- A, left antenna in B) presented in table 2.
1023, an incompletely preserved worker in a Measurements of leg segmentation (as mea-
piece of amber barely larger than the ant, sured on specimen A) presented in table 3.
from Sayreville, New Jersey (Middlesex COMMENTS: The discovery of this piece of
Co.), White Oaks outcrop, coll. Bob Mesak amber is highly significant and addresses
(fig. 5). The amber is an irregularly shaped questions of the social behavior of primitive
drop, 7 X 5 X 4 mm, made of clear yellow ants like }Sphecomyrma. As reviewed in Gri-
amber. Portions of some appendages are maldi et al. (1997), Dlussky (1987, 1988),
breached at the surface, and the petiole and and Poinar et al. (1999) questioned whether
gaster were similarly lost at the surface. +Sphecomyrma was a true ant since it had
Since very little amber exists between the ant such a short scape [but see response to Poin-
and surface of the amber piece, no trimming ar et al. (1999) by Grimaldi and Agosti
or polishing was possible. Still, details (2000b)]. With such a short scape, Dlussky
through the rough surface are highly visible argued that it would be impossible for
by immersing the piece in glycerine. +Sphecomyrma to antennate, and therefore it
ETyMOoLoGy: The specific epithet is a pat- was considered highly unlikely for +Sphe-
ronymic for Bob Mesak, who collected and comyrma to have been social. Among the ap-
donated this valuable specimen to the proximately 1700 fossiliferous pieces of New
AMNH. Jersey amber in the AMNH collection thus
far, four pieces contain worker or male sphe-
+Sphecomyrma freyi Wilson and Brown comyrmine ants. These ants are (and proba-
Figure 6 bly originally were) exceedingly rare, and the
probability that two workers would be pre-
+Sphecomyrma freyi Wilson and Brown, In Wil- served in one piece by chance alone is ex-
son et al., 1967: 8. Grimaldi et al., 1997: 12
tremely remote. It is most parsimonious to
(redescription of some features, new specimens,
explain the occurrence of two workers in the
neotype).
same piece as a result of social behavior.
MATERIAL: AMNH NJ-943, in amber from
New Jersey: Middlesex Co., Sayreville,
+Sphecomyrma sp.
White Oaks outcrop, collected by Keith Luz-
zi (fig. 6). The piece is transparent yellow, MATERIAL: AMNH NJ-942, a male in am-
originally much larger than now; was em- ber from New Jersey: Middlesex Co., Say-
10 AMERICAN MUSEUM NOVITATES NO. 3485
Fig. 6. Two workers of +Sphecomyrma freyi Wilson and Brown preserved in a single piece of New
Jersey amber (AMNH NJ-943).
reville, White Oaks outcrop. Collected by the COMMENTS: Venation and other details of
late Steve Swolensky. Specimen is in a clear this specimen are indistinguishable from
yellow piece of amber 5 X 7 mm, embedded AMNH NJ-242, described and figured by Gri-
in epoxy and trimmed to 1.5 mm thickness maldi et al. (1997) as }+Sphecomyrma? sp.
for a full lateral view of the ant. Measurements: Length of hind wing (forewing