Sa N G I RAN 493
of jaw appears to have curved smoothly across from
side to side, and smoothly and steeply back and
down. Bone of corpus a bit thinner in midline than
further back. Jaw appears to deepen markedly from
front to back. Postincisal plane was evidently fairly
short, but strongly sloped and somewhat convex. Be-
low, a very broad fossa lies midway down symphysis,
with an inferior transverse torus below. As seen on
the R, anterior root of ramus takes origin just behind
region of Ml (thus the rising ramus would have
totally masked M3). Corpus itself bulged laterally in
front of ramal root.
M1 would have been smaller, at least m/d, than
preserved M3. M3 elongate and subovoid in occlusal
outline, with some fissuring of its occlusal enamel.
Subdivided hypoconulid occupies entire distal portion
of crown. Hypoconid small and squeezed between
large hypoconulid and protoconid. Wedge-shaped,
shallow, centrally positioned fovea intrudes somewhat
between bases of protoconid and metaconid. All cusps
quite peripherally placed, thereby opening up a large
central basin. Roots appear not to have been divided,
at least on buccal side.
Sungirun 9. Partial mandible from just L of mid-
line to just behind RM2. Preserves alveoli for R and
LI1, RI2, partial RC, crowns of P1 and 2, M2 and 3,
and alveolus for M1. Tooth crowns all heavily worn,
and specimen quite eroded.
Front of jaw taller than posterior part of corpus.
Jaw very narrow anteriorly. Tooth rows would have
been slightly divergent posteriorly, although quite
close together (thus dental arcade would have been
rather narrow and almost V shaped, although lateral
bulge of corpus below Ml widens jaw externally).
Symphyseal region preserved externally below I alve-
oli and along base of jaw. Preserved bone perfectly
smooth (no keel, mental fossae, or thickened inferior
margin). In profile, symphyseal region flat but
slightly backwardly sloping (more so if occlusal sur-
faces of teeth held horizontal, in which case inferior
margin slopes up and back). Inferiorly the long, nar-
row digastric fossa faces down and back. Postincisal
plane long and shallowly concave, sloping strongly
back and down from alveolar crest. Below is indica-
tion of a low keel of bone in genial region. From
inside to outside, symphyseal region thin compared
to bone of corpus behind. Moderate size mental
foramen lies under P2, about halfway down corpus.
Anterior edge of root of ramus takes origin below
M2; rises gently to obscure most of M3. Internally,
no indication of mylohyoid line; long, shallow sulcus
parallels inferior margin.
I alveoli appear to have been small, I1 alveoli
slightly laterally compressed. C root and crown were
also apparently of modest size. C crown seems to have
been much smaller than P1; preserves evidence of bul-
bous lingual swelling. Pl was more asymmetrical than
P2. P1 apparently bore small metaconid that lay oppo-
site slightly mesially placed protoconid. Distolingual
corner of P1 was distended both distally and lingually
(thus crown was wider b/l distally than mesially). P2 less
swollen distolingually (thus lingual side straighter). P2
apparently had a small metaconid that lay directly oppo-
site slightly mesially placed protoconid. P2 may also
have had a posterior fovea. P1 and 2 appear to have
been a bit more swollen buccally than lingually. M2 no-
ticeably longer m/d than M3. Distal end of M2 was
probably rounded, as in M3; M2 was probably not as
ovoid overall as M3. M2 is a rather long, narrow, almost
rectangular tooth. M2 and M3 appear to have had all
cusps peripherally placed. M2 metaconid and proto-
conid lie opposite one another and very mesially (thus
talonid huge). M3 apparently similar. M3 and probably
M2 had small protostylids and moderately crenulated
occlusal surfaces. Tv12 and M3 root bifurcation was close
to neck. Region of M1 may have been abscessed (cavity
buccal to two normal-looking alveoli), which might
explain the lateral bulge in corpus bone below.
The two mandibles described below are more
similar to each other than to those just listed.Sungirun 33. Fragment of mandible with RM2.
Corpus shallow and quite thick m/l at mid-height,
although it thins markedly to inferior margin. Anterior
root of ramus takes origin below M2. Apparently no
mylohyoid line; a tall, shallow sulcus parallels inferior
margin internally. M2 eroded but only slightly worn.
Lingual cusps very peripherally placed. Buccal cusps
compressed, a little less peripherally placed, and much
lower than lingual cusps. Peripheral placement of cusps
produces broad, long central basin that dominates
crown. Buccal side has more distinct slope than lingual
side. Surface of tooth (thus cusps) subdivided by
network of deep grooves. Hypoconulid small, centrally
placed, wedge shaped. Occlusal outline ovoid.Sungirun Sb 8013. R mandibular fragment with
P2-M3. Possibly associated with a calotte at
GMUCM, Yogyakarta. Teeth quite worn; inferior
part of corpus missing.