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Biology Letters
ELECTRONIC SUPPLEMENTARY MATERIAL
A Middle Triassic thoracopterid from China highlights the evolutionary origin of
over-water gliding in early ray-finned fishes
Guang-Hui Xu1, Li-Jun Zhao2 and Chen-Chen Shen1
1Key
Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of
Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
2Zhejiang
Museum of Natural History, Hangzhou, Zhejiang 310014, China
(a) Methods
Illustrations were drawn manually, and then prepared using Adobe Photoshop and Illustrator software packages
(CS4). The relative position of fins and scale count are expressed in a scale formula following Westoll [1].
Characters were mainly adopted or modified from Xu et al. [2]. They were treated as unordered and weighted
equally. The data matrix was subjected to the parsimony analysis in PAUP* (version 4.0b10) [3]. Tree searches
were conducted using the branch-and-bound algorithm. WinClade 1.00.08 [4] was used to trace the character
transformation in the cladogram.
(b)
Taxonomic comments on ‘Thoracopterus’ wushaensis
‘Thoracopterus’ wushaensis [5] is a recently reported thoracopterid on the basis of five specimens from the same
fossil beds as those of Potanichthys xingyiensis [2]. The fossil locality of ‘Thoracopterus’ wushaensis is about 5
km away from the type locality of Potanichthys in Xingyi, Guizhou Province, China. Both taxa are ‘four-winged’
thoracopterid gliders because they have wing-like paired fins and an asymmetrical caudal fin with the lower caudal
lobe noticeably larger than the upper lobe, resembling Thoracopterus and Gigantopterus [6]. Comparison within
the Thoracopteridae, ‘Thoracopterus’ wushaensis [5] and Potanichthys [2] are more closely related to
Gigantopterus than to Thoracopterus in having an almost naked body. ‘Thoracopterus’ wushaensis should be
moved out of the genus Thoracopterus; it is probably a younger synonym of Potanichthys xingyiensis. However, a
detailed comparison between these two taxa is still difficult, because the holotype of ‘Thoracopterus’ wushaensis
was poorly preserved and incompletely described ([5]; see below); a morphological redescription and a taxonomic
revision of this taxon are pending. Thus, ‘Thoracopterus’ wushaensis has not been included in this analysis.
Supplementary Figure S1. Holotype of ‘Thoracopterus’ wushaensis (from [5]).
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(c)
Strict consensus of six MPTs
Supplementary Figure S2. Strict consensus of six MPTs (TL=142 steps, CI= 0.6127, RI= 0.7901, RC= 0.4841),
illustrating phylogenetic positions of Wushaichthys and Peripeltopleurus within the Neopterygii. Character
changes indicated with solid circles are unique.
(d)
Material examined and references.
BMNH, Natural History Museum, London, UK;
IVPP, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
PIMUZ, Paläontologisches Institut und Museum, Uiversität Zürich, Zürich, Switzerland
ZMNH, Zhejiang Museum of Natural History, Hangzhou, China
Amia calva: Grande and Bemis [7]
Lepisosteus osseus: Grande [8]
Exocoetus and Cypselurus: Breder [9]
Dapedium: Patterson [10,11]; Thies and Herzog [12]
Dorsetichthys (Pholidophorus) bechei: Patterson [11]; Arratia [13]
Leptolepis coryphaenoides: Patterson [11]; Arratia [14]
Perleidus: BMNH P16247, 16248, 19580–19584, 19587–19592, 19595–19599, 19603–19620, 19622, 19623;
Lehman [15]; Patterson [11]
Semionotus elegans: Olsen and McCune [16]; Cavin [17]; López-Arbarello [18]
Watsonulus eugnathoides: Olsen [19]; Grande and Bemis [7]
Peltopleurus rugosus: Bürgin [20], PIMUZ T2904
Gigntopterus teller: Griffith [6]
Luganoia lepidosteoides: Bürgin [20]
Peripeltopleurus vexillipinnis: Bürgin [20], PIMUZ A/I 3687, T4332, 193, 473, 495, 718, 737, 1136
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Peripeltopleurus hypsisomus: Bürgin [20], PIMUZ T1211, 2150, 2869
Potanichthys xingyiensis: Xu et al. [2]
Thoracopterus niederristi: Griffith [6], Lehman [21], BMNH P1098
‘Thoracopterus’ martinisi: Tintori and Sassi [22]
‘Thoracopterus’ magnificus: Tintori and Sassi [22]
Australosomus kochi: Nielsen [23], BMNH P17141–17143, 17156, 17157, 17160, 17161, 20940–20945
(e)
Characters and character states used in the phylogenetic analysis.
1.
Skull: no more than one-fourth of total length (0); roughly one-third of total length (1).
2.
Post-temporal fossa: rudimentary (0); well developed (1); lost (2).
3.
Sub-temporal fossa: present (0); absent (1).
4.
Dilatator fossa above hyomandibular facet: absent (0); present (1).
5.
Lateral cranial canal: absent (0); present (1).
6.
Posterior myodome: present (0); absent (1).
7.
Posterior myodome: paired (0); enlarged into a median cavity (1).
8.
Anterior myodome: present (0); absent (1).
9.
Number of anterior myodome: paired (0); a median single (1).
10.
Parasphenoid/basioccipital contact: absent (0); present (1).
11.
Basipterygoid process: present (0); absent (1).
12.
Internal carotid foramen on parasphenoid: absent (0); present (1).
13.
Efferent pseudobranchial foramen on parasphenoid: absent (0); present (1).
14.
Pterotic: present (0); absent (1).
15.
Intercalar: present (0); absent (1).
16.
Extrascapular: present (0); absent (1).
17.
Sphenotic with small dermal component: absent (0); present (1).
18.
Rostral as a discrete element: present (0); absent (1).
19.
Shape of rostral: as a deep cap on snout apex (0); reduced to a narrow tube (1).
20.
Rostral/frontal contact: absent (0), present (1).
21.
Anteriormost lacrimal: as part of orbital ring (0); anterior to orbital ring (1).
22.
Tube-like canal bearing anterior arm of antorbital: absent (0); present (1).
23.
Foramen for olfactory nerves on premaxilla: absent (0); present (1).
24.
Peg-like anterior process of maxilla: absent (0); present (1).
25.
Nasal involvement of anterior border of orbit: present (0); absent (1).
26.
Antorbital involvement of anterior border of orbit: present (0); absent (1).
27.
Posttemporal: contacts extrascapular anteriorly (0); contacts the extrascapular anterolaterally and separates
this bone from contact with its counterpart (1).
28.
Parietal as a discrete element: present (0); absent (1).
29.
Nasal process of premaxilla that tightly sutured to frontals: absent (0); present (1).
30.
Premaxillae: paired (0); fused (1).
31.
Number of lacrimal bones: single (0); two or more (1).
32.
Vomers in adults: paired (0); fused (1).
33.
Frontal: elongated (0); laterally expanded (1).
34.
Supraorbital sensory canal: ending at frontal (0); ending at parietal (1).
35.
Infraorbitals posterior to antorbital and below dermosphenotic: two or three elements (0); four or more
elements (1).
4
36.
Supraorbitals (including adnasal): absent (0); present (1).
37.
Number of supraorbitals between adnasal and dermosphenotic: single (0); two or more (1).
38.
Suborbitals: present (0); absent (1).
39.
Number of suborbitals: single element (0); two or more (1).
40.
Dermohyal: present (0); absent (1).
41.
Mobile premaxilla: absent (0); present (1).
42.
Maxilla free from preopercle: absent (0); present (1).
43.
Mobile maxilla in cheek: absent (0); present (1).
44.
Supramaxilla: absent (0); present (1).
45.
Number of supramaxilla: one (0); two (1).
46.
Supra-angular: present (0); absent (1).
47.
Coronoid process: absent (0); present (1).
48.
Suspensorium angle: acute (0); nearly vertical (1).
49.
Symplectic: absent (0); present (1).
50.
Symplectic involment of jaw joint: absent (0); present (1).
51.
Quadratojugal: present (0); absent (1).
52.
Shape of quadratojugal: plate-like (0); splint-like (1).
53.
Uncinate processes on epibranchials: absent (0); present (1).
54.
Number of hypobranchials: three (0); four (1).
55.
Opercle: larger than subopercle (0); roughtly equal to or smaller than subopercle (1).
56.
Shape of preopercle: boomerang-shaped (0); narrow and vertical, bearing a tapering anterior process (1);
oval-shaped (2); crescent-shaped (3); L-shaped (4).
57.
Hinge position of jaws: far backwards from posterior margin of orbital (0); near or well anterior to post
margin of orbital (1).
58.
Suborbital/maxilla contact: absent (0); present (1).
59.
Interopercle: absent (0); present (1).
60.
Median gular: present (0); absent (1).
61.
Lateral gular: present (0); absent (1).
62.
Presupracleithrum: present (0); absent (1).
63.
Posterior margin of maxilla: straight or slightly convex (0); concave with a posterior maxillary notch (1).
64.
Clavicle: present (0); absent (1).
65.
Clavicle: large, cap anterior end of cleithrum (0); reduced into small plates on postbranchial lamina of
cleithrum (1).
66.
Fringing fulcra: absent (0); present (1).
67.
Pectoral fin enlarged as wing: absent (0); present (1).
68.
Diural caudal skeleton: absent (0); present (1).
69.
Division of hypurals into dorsal and ventral groups (a gap between hypurals 2 and 3): absent (0); present (1).
70.
Dorsal and anal fins: rays more numerous than radials (0); rays and radials equal (1).
71.
Pelvic fin enlarged as wing: absent (0); present (1).
72.
Dense lepidotrichial segments of pectoral fin rays between innermost principle pectoral fin ray and body:
absent (0); present (1).
73.
Anal fin: larger than or equal to dorsal fin (0); smaller than dorsal fin (1).
74.
Hooklets on anal fin of supposed male: present (0); absent (1).
75.
Dorsal and anal fin rays: segmented throughout length (0); segmented distally (1).
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76.
Caudal fin: forked (0); unforked (1).
77.
Caudal fin: lower lobe slightly shorter than or equal to upper lobe (0); lower lobe longer than upper lobe
present (1).
78.
Uroneural: absent (0); present (1).
79.
Median caudal neural spines: absent (0); present (1).
80.
Body scales: body fully covered (0); reduced to a few (no more than four) rows of scales in caudal region (1);
entirely lost (2).
81.
Scale shape: rhomboid (0); circular to cycloid (1).
82.
Dorsal ridge scales (with posteriorly directed spines): absent (0); present (1).
83.
Horizontal row of scales along lateral line: slightly deeper than those scales above or below lateral line (0);
much deeper than those scales above and below lateral line (1); lost (2).
84.
(f)
Ossified vertebral centra: absent (0); present (1).
Data matrix of taxa and characters
‘T’. magnificus and ‘T’. martinisi respectively represent ‘Thoracopterus’ magnificus and ‘Thoracopterus’ martinisi.
The states of three characters (nos. 4, 7, 58) are constant throughout the selected taxa and are not included when
performing this phylogenetic analysis.
0000000001 1111111112 2222222223 3333333334 4444444445 5555555556 6666666667 7777777778 8888
Taxa
1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234
Australosomus
0001001000 0000000000 00?00?00?? 0?0000-000 0000-0000- 0000000000 0000000000 0000000000 0000
Dapedium
0101101001 111?00?001 000?100010 0001010011 01110?1110 ???0041010 100??10001 00101000?0 0100
Gigantopterus
0??1??1??? ?????0?00? 000010?10? 0?10011??? 00?0-??1?? ????010?0? ??0??01001 111?1010?1 0020
Leptolepis
0101101011 1110000010 0001100010 0101011001 1111101110 1-10041010 1101-00011 0010100110 1001
Luganoia
0??1??1??? ?????0?1-- 00001-0111 0?01011010 0010-?11?? 00??101000 1?0??00??1 001011-??0 0010
Peltopleurus
0??1??1??? ?????0?000 0000000000 0?00011010 0000-?01?? ????00000? ??0??10??1 0011100??0 0010
Perleidus
0001101??0 100000?000 0000000000 0?01011000 0000-001?? ????100000 000??10001 0010100??0 0000
Dorsetichthys
0101101011 1110000010 0001100010 0101111001 1111101110 0110041010 100??10011 0010100110 0000
Semionotus
0101?????1 1001101011 1111110010 1001111001 0111001110 0111031011 1000110001 0010100010 0100
Potanichthys
1????????1 ?00????000 000010?101 0?1001101? 0000-?01?? ????01000? ??0??01001 1111101011 0020
Wushaichthys
0????????? ?????0?000 0000101101 0?1001001? 0000-?01?? 1-??010?00 0000010??1 0011100??0 0010
Peripeltopleurus
0????????? ?????0?000 0000101101 0?1001101? 0000-?01?? 1-??010?00 000??10??1 0011101??0 0010
Thoracopterus
0????????? ?????0?001 000010110? 0?10010??? 0000-?01?? ????010?0? ??0??01??1 111?101??0 0010
‘T’. magnificus
0????????? ?????0?000 0000101101 0?100??00? 0000-?01?? ????010000 ?00??01001 111?101012 -020
‘T’. martinisi
0????????? ?????0?000 0000101101 0?100??00? 0000-?01?? ????010000 ?00??01001 111?101012 -020
Watsonulus
0101101000 100?00?011 0111100010 0001111011 0111001111 ??11020010 1010010001 00101000?0 0000
Amia
0111001001 0001001011 0111100010 000110-1-1 0111001111 1-11031-10 1010100001 001011-010 1001
Cypselurus
01010011-1 0110010011 000010-010 011000-1-1 1110-11110 1-10041-11 1101-01111 1010101110 1001
Exocoetus
01010011-1 0110010011 000010-010 011000-1-1 1110-11110 1-10041-11 1101-01111 0010101110 1001
Lepisosteus
021111-1-1 1001101011 1111110010 1000111010 0100-01110 0111041001 1000110001 000011-010 0101
6
(g)
1
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