Chondrichthyes Cladogram

As with all phylogenetic studies, this one is a work in progress as of early 2001. It will change with the addition of more fish and more information.

Character matrix
No.	Character	State 0	State 1	State 2	State 3	State 4
0	mineralized endoskeletal tissue	perichondral bone	prismatic calcified cartilage	superficially continuous	trabecular
1	ampullary system	not present	skin tight/ thin if present	rostral ampullary dome
2	supraorbital cartilage	present	absent
3	frontal clasper	absent	median	single pair	median, extremely elongate	multiple pairs
4	anterior braincase opening	closed / small opening	large / precerebral fontanelle
5	rostrum:basal plane	180 degrees	greater than 180 degrees
6	ethmoid % of neurocranium	<25%	25-40	40-50	>50
7	orbital % of neurocranium	35-46	>46	<35%
8	postorbital % of neurocranium	25-40	15-25	>40	<15%
9	anterior ventral braincase	narrow	wide
10	posterior ventral braincase	narrow	wide
11	palatine area shape	generalized	medial shelf
12	palatoquadrate: basitrabecular articulation	present	absent	fused
13	pq-postorbital articulation	absent	under postorbital process	on posterior side of postorbital process	otic-postotic
14	basitrabecular process attitude	in line with postorbital	flared ventrolateral to postorbital	flared antero-ventrolaterally	absent
15	basitrabecular/pq articular position	postorbital	orbital	antorbital	absent
16	suspensorium	autodiastyly	hyostyly	amphistyly	holostyly	methyostyly
17	extravisceral cephalic cartilages	prominent labials	few/reduced labials	none	Pre-mandibular jaw bones
18	palatoquadrate anteriad	separate	median symphysis	parallel (parasymphysial) extension
19	palatoquadrate- otic process shape	slight/ postorbital	dorsally recurved	posteriorly extended	dorsally expanded
20	meckel's-quadate articulation	postorbital	orbital	preorbital
21	mandibular mineralization	bone	prismatic calcified cartilage	solid fibrocartilage	other mineralization
22	Upper parasymphysial cartilage(s)	small	visible, moderate	anteriorly extended	absent
23	Lower symphysial element	present between mandibles	extended anteriad	absent
24	gill openings	single opercular valve	separate gill openings
25	epihyal	opercular support	mandibular support
26	branchial denticles	present	absent
27	ventral hyoid and branchials	normal	anteriorly elongate
28	branchial basket	subotic to postcranial	subcranial	principally postcranial
29	tooth families per jaw	about 10- 15	> 15	< 9	< 4
30	extended neurocranial rostrum	absent	present
31	functional jaw tooth families	1-2 per family	pavement occlusion	reduced or absent
32	tooth shapes on jaw	homodont	heterodont	teeth & tooth plates	plates alone
33	occlusion	cutting / piercing	crushing / grinding	both	absent/na
34	lower symphysial family	generalized	prominent	whorl	fused plate	absent
35	upper parasymphysial family	generalized	prominent	whorl	fused plate	absent
36	tooth cusps on jaw	single	multiple in-line	reduced / suppressed	absent
37	cusp shape	high, sharp	low, rounded	bladed	heterodont	absent
38	crown base	generalized	lingual, labial ridges	lingual basin	basin and ridges	absent
39	tooth root	short below crown	long below crown	extended lingual	fused	below lingual edge
40	root shape	straight below crown	lingual s-shape	lingual shelf	fused	below lingual edge
41	enameloid layers	radial crystallite	complex	absent
42	orthodentine	present	absent
43	osteodentine	absent	present
44	paired, upper dental positions	> 3 (teeth)	2 anterior, 1 posterior	1 anterior, 1 posterior	1 posterior	absent
45	paired anterior lowers	> 3 (teeth)	2 anterior	1 anterior	absent
46	middle, lower condition	tooth	whorl	plate	absent
47	posterior dental histology	coronal tooth tissues	tritoral dentine	pleromin tritors	other	absent
48	anterior and middle dental surfaces	coronal tooth tissues	limited tritors	complete coverage	bone, no tritor	absent
49	anterior dental histology	coronal tooth tissues	tritoral dentine	pleromin tritors	bone, no tritor	absent
50	scale type	placoid	zonal growth	fused placoid	absent	ganoid
51	head scale coverage	generalized	both generalized & specialized	specialized areas only	absent
52	head scale modifications	generalized	enlarged scales/spines	plates	absent
53	head dermal bones	absent	present
54	head lateral line scales	small, simple, oriented	thin rings	bones	canal(s) enclosed in plates	absent
55	ethmo-rostral scales	generalized	spikes	enlarged denticles	few plates	absent
56	supraorbital scales	generalized	enlarged scales/spines	plates	absent
57	otic scales	generalized	enlarged scales/spines	plates	absent
58	occipital scales	generalized	enlarged scales/spines	absent
59	mandibular squamation	generalized	posterior specialization	longitudinal specialization (plates)	absent
60	mandibular bones	present	absent
61	posterior mandibular scales	generalized	small sharp spine	broad spine	buttressed plate	absent
62	basitrabecular rim scales	generalized	few large denticles	plate	plate and spine	absent
63	body scales	generalized	generalized and specialized areas	only specialized areas	absent
64	enlarged paired dorsal body scales	generalized	1st dorsal to caudal	between fins	past 2nd dorsal	absent
65	dorsal fin squamation	complete covering	crest of fin only	upon radials	absent
66	squamation /sex	monomorphic	sexually dimorphic
67	lateral line scales of body	small, simple, oriented	rings	canal through scales	none
68	pectoral fin position	ventrolateral	mid-flank	nape of the neck
69	pectoral girdle	principally endoskeletal	principally exoskeletal
70	coracoid length	normal	extended anteriorly	truncated anteriorly
71	pectoral radials	no radials on girdle	~ 50% on metapterygium	most on girdle
72	pectoral fin	uniserial	partially biserial	entirely biserial
73	pectoral basals	unibasal	metapterygium dominant	tribasal	multibasal
74	pectoral post-metapterygial axis	absent	1-4 small elements	>4 small elements
75	pelvic girdle mineralization	bone	prismatic calcified cartilage	solid, 3-dimensional
76	pelvic dorsal process	absent	short	tall
77	pelvic basipterygium	minor or absent	elongate	triangular
78	pelvic radials	majority on girdle	~ 50% on basipterygium	majority on basipterygium
79	prepelvic tenaculum	absent	adjacent to fin	anterior to fin
80	anal fin and/or anal plate	absent	present
81	dorsal fin numbers	two fins	one fin
82	dorsal spines	anterior fin only	two spines	no spines
83	anterior dorsal fin	large	small flap	absent	rod
84	anterior dorsal fin and/or spine support	basal plate / radials	synarcuum	on head	shoulder girdle	absent
85	anterior dorsal spine	superficial insertion	long, mobile	deeply fixed	absent
86	anterior dorsal presence	found in both sexes	absent in both sexes	sexually dimorphic
87	anterior dorsal fin/spine development	at birth	at puberty
88	anterior dorsal spine shape	posteriorly directed, narrow	triangular	forwardly curved	absent
89	anterior dorsal spine enameloid, den	present	absent	no spine
90	posterior dorsal fin	short	elongate	absent
91	posterior dorsal fin base	all radials	basal plate & radials	basal plate	other
92	posterior dorsal spine	absent	superficial insertion	deeply fixed
93	caudal fin	heterocercal	extended heterocercal	homocercal	diphycercal
94	caudal endoskeleton	serial hypochordal	epichordal component	fusions / expansions	homocercal
95	notochordal calcification	uncalcified	chordacentra	complete centra
96	vertebral arcual mineralization	uncalcified	regionalized	entire column

Top of page