728:) have the most advanced venom delivery method of any snake. Each maxilla is reduced to a nub supporting a single hollow fang tooth. The fangs, which can be as long as half the length of the head, are folded against the roof of the mouth, pointing posteriorly. The skull has a series of interacting elements that ensure that the fangs rotate into biting position when the jaws open. Solenoglyphous snakes open their mouths almost 180 degrees, and the fangs swing into a position to allow them to penetrate deep into the prey. While solenoglyph venom is typically less toxic than that of
1109:
378:
585:
654:
699:
31:
75:
682:) have shortened maxillae bearing few teeth except for a substantially enlarged fang pointing downwards and completely folded around the venom channel, forming a hollow needle. Because the fangs are only a fraction of an inch long in even the largest species, these snakes must hang on, at least momentarily, as they inject their venom. Some
538:
617:
called "rear-fanged". In order to envenomate prey, an opisthoglyphous snake must move the prey into the rear of its mouth and then penetrate it with its fangs, presenting difficulties with large prey although they can quickly move smaller prey into position. The opisthoglyphous dentition appears at
972:
A snake has from 175 to more than 400 vertebrae in its backbone. The means by which vertebrae are secured are twofold: either a ball and socket joint, or zygopophyses, which stick out from each vertebra to poke rear-pointing projections from the vertebrae ahead of it. This results in a spine
790:
I. Quadrate articulating with the cranium, supratemporal absent; mandible much shorter than the skull, with coronoid bone; maxillary small, on lower aspect of cranium; pterygoids not extending to quadrate; nasals forming long sutures with the premaxillary, prefrontals, and frontal:
807:
A. Mandible with coronoid bone; nasals in sutural contact with frontals and prefrontals; transverse bone short, not projecting much beyond cranium; maxillary not half as long as mandible, which is not longer than skull (to occiput):
1063:), may be expanded and plate-like above, and short or moderately long transverse processes to which the ribs are attached by a single facet. The centra of the anterior vertebrae emit more or less developed descending processes, or
566:) have no specialized teeth; each tooth is similar in shape and often size. When teeth vary in size, as in some bird eaters, they do not vary in shape. Most aglyphous snakes are non-venomous; some, like
365:, in which the skull is very compact and the maxillary much reduced. In the former this bone is loosely attached to the lower aspect of the cranium; in the latter, it borders the mouth and is
437:. It allows the maxilla to pivot in the plane of the photograph, and while it does not increase gape, it does facilitate the complex action by which the snake draws prey into its mouth.
245:, which may be very long, and the maxillary often emits a process towards the palatine, the latter bone being usually produced inwards and upwards towards the anterior extremity of the
762:
Common names for the various types of snake dentition originate largely from older literature, but still are encountered in informal publications. Aglyphous snakes are commonly called
514:. The latter form an "inner row" of teeth that can move separately from the rest of the jaws and are used to help "walk" the jaws over prey. Several snake lineages have evolved
889:
Quadrate longer than supratemporal; maxillary much longer than quadrate, nearly straight in front of prefrontal; a large vacuity between the frontal bones and the basisphenoid:
613:, which normally angle backward and are grooved to channel venom into the puncture. Since these fangs are not located at the front of the mouth, this arrangement is
1143:, attached to the lower branch of the first bifurcate transverse process of the lumbar vertebrae, bearing three short bones, the longest of which, regarded as the
369:
joined to the premaxillary and the prefrontal. Both the transverse bone and the supratemporal are absent, but the coronoid element is present in the mandible.
637:, respectively, after each underestimated the effects of the bite and failed to seek medical help. Opisthoglyphous snakes are found mostly in the families
920:
2. Maxillary much abbreviated and erectile; supratemporal not half as long as skull; mandible much longer than skull; basioccipital with a strong process.
750:
is solenoglyphous but the fangs swing out sideways, allowing it to strike without opening its mouth, perhaps allowing it to hunt in small tunnels.
1285:
882:
b. Maxillary not half as long as mandible, which is longer than skull; supratemporal not half as long as skull, projecting beyond cranium.
427:. It is highly mobile in most directions, allowing a wider gape (i.e., the snake can open its mouth wider) and greater jaw flexibility.
1260:
1092:
In the caudal region, elongate transverse processes take the place of ribs, and the haemapophyses are paired, one on each side of the
800:
II. Quadrate suspended from the supratemporal; mandible at least as long as the skull; pterygoids extending to quadrate or mandible.
1055:
in addition to the cup-and-ball on the centrum, and interlock by parts reciprocally receiving and entering one another, like the
297:
618:
least two times in the history of snakes. The venom of some opisthoglyphous snakes is strong enough to harm humans; notably,
35:
529:
Most snakes can be placed into one of four groups, based on their teeth, which correlate strongly with venom and lineage.
252:
The quadrate is usually large and elongate, and attached to the cranium through the supratemporal (often regarded as the
357:
The deviation from the normal type is much greater still when we consider the degraded wormlike members of the families
898:
Quadrate not longer than supratemporal; maxillary little longer than quadrate, strongly curved in front of prefrontal:
906:
Quadrate longer than supratemporal; maxillary little longer than quadrate, nearly straight in front of prefrontal:
856:
Supratemporal not half as long as skull, projecting but slightly beyond cranium; mandible much longer than skull:
686:
have modified fang tips allowing them to spray venom at an attacker's eyes. This form of dentition is unique to
1194:
1051:, just below the base of the neural spine. Thus the vertebrae of snakes articulate with each other by eight
511:
269:
1320:
732:, this system allows them to deeply inject large quantities of venom. This form of dentition is unique to
622:
354:
in front of the frontals; the dentary may be freely movable, and detached from the articular posteriorly.
989:
953:
847:
Supratemporal not half as long as skull, projecting far beyond cranium; mandible much longer than skull:
342:; the pterygoids may taper and converge posteriorly, without any connection with the quadrate, as in the
234:
1024:
992:, all of which, except the first or first three, bear long, movable, curved ribs with a small posterior
865:
Supratemporal not half as long as skull, not projecting beyond cranium; mandible not longer than skull:
193:
276:
required by the passage of prey, often much exceeding the size of the mouth. For the same reason, the
1199:
1001:
838:
Supratemporal half as long as skull, projecting far beyond cranium; mandible much longer than skull:
414:
343:
242:
377:
1064:
351:
238:
147:
1069:
1059:
joints. The precaudal vertebrae have a more or less high neural spine which, as a rare exception (
840:
609:("rearward grooves") snakes possess venom injected by a pair of enlarged teeth at the back of the
246:
159:
1325:
891:
667:
334:
315:
is reduced to a pair of cartilaginous filaments situated below the trachea, and united in front.
229:
are long and parallel to the axis of the skull, the latter diverging behind and extending to the
80:
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908:
366:
139:
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1256:
1056:
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123:
1043:, broad, flattened, and overlapping, and of a pair of anterior wedge-shaped processes called
1217:
Animales venenosos. Vertebrados terrestres venenosos peligrosos para el ser humano en España
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170:
754:(blind burrowing snakes) typically have few teeth, often only in the upper or lower jaw.
346:; the supratemporal may be much reduced, and wedged in between the adjacent bones of the
584:
947:
683:
626:
546:
390:
382:
226:
155:
151:
63:
1246:
Rose, Walter; The reptiles and amphibians of southern Africa; Pub: Maskew Miller, 1950
265:) the transverse bone is forked and articulates with the two branches of the maxilla.
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is provided with additional articular surfaces in the form of pre- and post-
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30:
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Engelmann, Wolf-Eberhard. Snakes (No. 05352). Publisher
Bookthrift 1982.
1016:, the ribs or transverse processes have the branches regularly superposed.
996:
at the base, the last of these ribs sometimes forked; two to ten so-called
338:); the maxillary may be much abbreviated and movable vertically, as in the
537:
471:: the joint between the supratemporal and parietal. Immobile, except for
993:
793:
712:
610:
410:
285:
208:
104:
46:
774:; and both Proteroglyphous and Solenoglyphous snakes are referred to as
207:
is single and small and as a rule, connected with the maxillary only by
1166:
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849:
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of the mandible; the pterygoid is connected with the maxillary by the
1152:
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465:: allows the lower jaws to bow outwards, further increasing the gape.
1100:
the seven or eight last vertebrae are enlarged and fused into one.
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29:
519:
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985:
59:
945:
The vertebrae number 130 to 500 - in the
European forms 147 (
100:
to allow the snake to swallow prey far larger than its head.
173:
is situated, on each side, between the frontal bone and the
1307:
External and
Internal snake anatomy with postmortem images.
158:. The basioccipital may bear a curved ventral process or
1027:, with the nearly hemispherical or transversely elliptic
518:
which is typically delivered by specialized teeth called
177:, and may or may not be in contact with the nasal bone.
1169:, and rudimentary femur, the ischium forming a ventral
572:, are considered mildly venomous. The feature is not a
1203:, 2nd edition. London: Methuen & Co., Ltd., 1913.
1151:
which usually appears externally on each side of the
455:
to upturn slightly, increasing gape and assisting in
304:
and a few other small families, are connected at the
1047:, fitting into a pair of corresponding concavities,
150:, or a simple knob formed by the basioccipital; the
786:Modifications of the skull in the European genera:
1067:, which are sometimes continued throughout, as in
744:A few snakes do not conform to these categories.
130:region. The nose is less ossified, and the paired
973:well-adapted to the snake's method of movement.
318:There are various modifications according to the
824:1. Maxillary elongate, not movable vertically.
385:, with visible kinetic joints labeled. Red =
8:
1272:Campbell, Sheldon; Shaw, Charles E. (1974).
122:, which is large and extends forward into a
134:are often attached only at their base. The
96:is a very complex structure, with numerous
322:. A large hole may be present between the
272:are more or less movable to allow for the
1120:No living snake shows any remains of the
423:: the joint between the quadrate and the
1208:
1116:showing the bones inside the anal spurs
1012:with simple transverse processes. When
433:: the joint between the prefrontal and
308:by a very extensible elastic ligament.
831:a. Maxillary half as long as mandible.
188:behind, rarely also above, and in the
103:The typical snake skull has a solidly
817:B. No coronoid bone; nasals isolated.
7:
984:(composed of two vertebrae) without
782:Taxonomic key of skull modifications
200:between it and the prefrontal bone.
280:of the lower jaw, which consist of
25:
1000:without ribs, but with bifurcate
729:
296:elements, with the addition of a
1004:(lymphapophyses) enclosing the
758:Informal or popular terminology
417:to the joint in mammalian jaws.
381:Lateral view of the skull of a
268:The quadrate and maxillary and
184:, usually present, borders the
1:
1184:: a single bone on each side.
1147:, terminates in a claw-like
1274:Snakes of The American West
1342:
1008:; and a number of ribless
118:extending downward to the
50:consists primarily of the
34:Skelton of a snake at the
1215:Bruna Azara, C. (1995). "
766:; opisthoglyphous snakes
373:Joints of the snake skull
443:: the joint between the
1236:LD50 for various snakes
1195:George Albert Boulenger
936:Maxillary bone hollow:
512:lateral pterygoid plate
66:remnants of the limbs.
1117:
1035:vertebrae), while the
927:Maxillary bone solid:
718:
672:
603:
556:
398:
326:and the basisphenoid (
270:palatopterygoid arches
85:
38:
36:Natural History Museum
1124:, but remains of the
1111:
1025:ball and socket joint
701:
656:
587:
540:
380:
154:is excluded from the
77:
33:
1200:The Snakes Of Europe
1002:transverse processes
413:and quadrate. It is
110:, with the separate
990:precaudal vertebrae
954:Coluber leopardinus
494:are located on the
235:articular extremity
27:Skeleton of a snake
1118:
968:Vertebrae and ribs
719:
673:
668:Ophiophagus hannah
604:
557:
399:
142:and formed by the
86:
81:Python reticulatus
39:
1287:978-0-394-48882-0
1057:mortise and tenon
1006:lymphatic vessels
629:were killed by a
599:Heterodon nasicus
552:Python bivittatus
205:premaxillary bone
194:supraorbital bone
136:occipital condyle
126:extending to the
16:(Redirected from
1333:
1292:
1291:
1269:
1263:
1253:
1247:
1244:
1238:
1233:
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1213:
1159:Leptotyphlopidae
1010:caudal vertebrae
998:lumbar vertebrae
978:vertebral column
451:. It allows the
259:In rare cases, (
182:postfrontal bone
21:
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1336:
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1278:Alfred A. Knopf
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1104:Vestigial limbs
1023:have the usual
980:consists of an
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684:spitting cobras
680:forward grooved
676:Proteroglyphous
659:proteroglyphous
651:
607:Opisthoglyphous
590:opisthoglyphous
582:
564:lacking grooves
535:
522:located on the
484:
482:Snake dentition
391:slightly mobile
375:
344:Amblycephalidae
313:hyoid apparatus
243:transverse bone
171:prefrontal bone
114:and the united
72:
28:
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18:Opisthoglyphous
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1299:External links
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1261:978-0896731103
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1128:are found in:
1114:Boelens python
1112:Skeleton of a
1105:
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722:Solenoglyphous
704:solenoglyphous
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627:Robert Mertens
620:herpetologists
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547:Burmese python
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383:Burmese python
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156:foramen magnum
152:supraoccipital
116:parietal bones
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1321:Snake anatomy
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1305:Snake Anatomy
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594:hognose snake
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387:highly mobile
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352:median suture
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112:frontal bones
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78:The skull of
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19:
1276:. New York:
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1098:rattlesnakes
1094:haemal canal
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1070:Tropidonotus
1068:
1041:zygapophyses
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975:
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841:Tropidonotus
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776:front-fanged
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726:pipe grooved
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679:
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649:Proteroglyph
643:Homalopsidae
623:Karl Schmidt
615:vernacularly
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605:
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580:Opisthoglyph
574:synapomorphy
567:
563:
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558:
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528:
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445:frontal bone
440:
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409:between the
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363:Glauconiidae
356:
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267:
260:
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251:
247:basisphenoid
220:
213:
202:
198:intercalated
179:
168:
160:hypapophysis
148:exoccipitals
120:basisphenoid
102:
87:
79:
62:, with only
42:
40:
1182:Typhlopidae
1149:pelvic spur
1082:Ancistrodon
1037:neural arch
988:; numerous
939:Ancistrodon
892:Coelopeltis
772:back-fanged
768:rear-fanged
747:Atractaspis
708:rattlesnake
694:Solenoglyph
359:Typhlopidae
335:Coelopeltis
218:is narrow.
214:The paired
132:nasal bones
1315:Categories
1189:References
1061:Xenopholis
1045:zygosphene
1033:procoelous
951:) to 330 (
740:Exceptions
663:king cobra
639:Colubridae
635:twig snake
569:Thamnophis
474:Dasypeltis
457:swallowing
449:nasal bone
389:, green =
329:Psammophis
274:distension
233:or to the
138:is either
1326:Skeletons
1177:Aniliidae
1171:symphysis
1161:: ilium,
1139:: a long
1096:. In the
1049:zygantrum
909:Tarbophis
868:Coronella
706:snake. A
661:snake. A
631:boomslang
592:snake. A
560:Aglyphous
545:snake. A
543:aglyphous
500:lower jaw
415:analogous
393:, blue =
367:suturally
340:Viperidae
306:symphysis
294:articular
254:squamosal
227:pterygoid
140:trilobate
128:ethmoidal
108:braincase
64:vestigial
56:vertebrae
1226:: 32-40.
1221:Bol. SEA
1089:genera.
1087:European
1085:, among
994:tubercle
794:Typhlops
764:fangless
724:snakes (
713:Crotalus
678:snakes (
611:maxillae
562:snakes (
510:and the
486:In most
411:mandible
395:immobile
298:coronoid
286:splenial
231:quadrate
209:ligament
146:and the
105:ossified
47:skeleton
1167:ischium
1137:Pythons
1029:condyle
859:Coluber
850:Zamenis
710:skull (
688:elapids
665:skull (
596:skull (
549:skull (
524:maxilla
504:maxilla
498:of the
496:dentary
463:Green B
441:Green A
435:maxilla
348:cranium
300:in the
290:angular
282:dentary
262:Polemon
190:pythons
175:maxilla
162:in the
124:rostrum
1284:
1259:
1165:, and
1153:cloaca
1126:pelvis
1079:, and
1076:Vipera
1053:joints
1021:centra
930:Vipera
872:Contia
734:vipers
633:and a
533:Aglyph
506:, the
502:, the
488:snakes
405:: the
320:genera
292:, and
164:vipers
98:joints
58:, and
1163:pubis
1145:femur
1141:ilium
1014:bifid
982:atlas
520:fangs
516:venom
492:teeth
431:Red C
421:Red B
407:joint
403:Red A
216:vomer
186:orbit
94:snake
92:of a
90:skull
70:Skull
52:skull
44:snake
1282:ISBN
1257:ISBN
1135:and
1133:Boas
1019:The
986:ribs
976:The
811:Eryx
641:and
625:and
469:Blue
453:nose
447:and
361:and
311:The
302:boas
278:rami
225:and
221:The
203:The
180:The
169:The
88:The
60:ribs
1219:".
1197:.
770:or
715:sp.
588:An
541:An
256:).
241:or
196:is
1317::
1280:.
1224:11
1073:,
957:).
870:,
778:.
736:.
702:A
690:.
657:A
645:.
526:.
490:,
332:,
288:,
284:,
249:.
211:.
192:a
166:.
54:,
41:A
1290:.
1173:.
1155:.
942:.
933:.
895:.
875:.
862:.
853:.
844:.
814:.
797:.
717:)
671:)
602:)
576:.
555:)
477:.
459:.
397:.
84:.
20:)
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