Table 3 List of irregular sea urchin taxa included in this study.

Echinoneoida Clark, 1925

Echinoneidae Agassiz & Desor, 1847

Echinoneus cyclostomus Leske, 1778

MRI (66 μm)³, dissection

NHM 1969.5.1.105, ZMB 4963

[50], this study

Cassiduloida Agassiz & Desor, 1847

Apatopygidae Kier, 1962

Apatopygus recens (Mortensen, 1948)

Dissection

ZMK Mortensen collection

this study

Cassidulidae Agassiz & Desor, 1847

Cassidulus caribaearum de Lamarck, 1801

MRI (81 μm)³

CASIZ 112632

[70], this study

Rhyncholampas pacificus (Agassiz, 1863)

Dissection

-

[13]

Echinolampadidae Gray, 1851

Echinolampas depressa Gray, 1851

MRI (81 μm)³

USNM E32955

this study

Neolampadidae Lambert, 1918

Neolampas rostellata Agassiz, 1869

MRI (81 μm)³, dissection

MNHN EcEh 330

this study

Clypeasteroida Agassiz, 1835

Clypeasteridae Agassiz, 1835

Clypeaster annandalei Koehler, 1922

Dissection

-

[51]

Clypeaster destinatus Koehler, 1922

Dissection

-

[51]

Clypeaster europacificus Clark, 1914

Dissection

CASIZ 101408

this study

Clypeaster humilis (Leske, 1778)

Dissection

-

[51]

Clypeaster rarispinus de Meijere, 1903

Dissection

-

[51]

Clypeaster reticulatus (Linnaeus, 1758)

MRI (81 μm)³

USNM 34282

[51], this study

Clypeaster rosaceus (Linnaeus, 1758)

MRI (96 μm)³, dissection

ZMB 2520

[13], this study

Arachnoididae Duncan, 1889

Arachnoides placenta (Linnaeus, 1758)

MRI (81 μm)³, dissection

ZMB 1439, CASIZ 93620, CASIZ 103170, CASIZ 94172

[51], this study

Laganidae Agassiz, 1873

Laganum bonani Klein, 1734

Dissection

-

[51]

Laganum decagonale de Blainville, 1827

Dissection

-

[51]

Laganum depressum Agassiz, 1841

MRI (86 μm) ³, dissection

NHM 1932.4.28.227-34

[51], this study

Laganum joubini (Koehler, 1922)

MRI (44 μm) ³

NHM 1979.1.25.52-60

this study

Laganum laganum (Leske, 1778)

MRI (81 μm)³

CASIZ 94344

[51], this study

Peronella lesueuri (Agassiz, 1841)

MRI (81 μm)³, dissection

MNHN EcEh 79

[51], this study

Peronella orbicularis Leske, 1778

MRI (81 μm)³, dissection

MNHN EcEh 77

[52], this study

Fibulariidae Gray, 1855

Echinocyamus pusillus (Müller, 1776)

MRI 20 × 18 × 18 μm³

-

[52], this study

Rotulidae Gray, 1855

Fibulariella acuta (Yoshiwara, 1898)

Dissection

CASIZ uncataloged material

this study

Rotula deciesdigitata (Leske, 1778)

MRI (81 μm)³, dissection

ZMB 2169

[53], this study

Echinarachniidae Lambert, 1914

Echinarachnius parma (de Lamarck, 1816)

Dissection

ZSM 20011676, CASIZ 157683

[40, 45, 51, 54], this study

Dendrasteridae Lambert, 1900

Dendraster excentricus (Eschscholtz, 1831)

Dissection

-

[54–58], this study

Scaphechinus griseus (Mortensen, 1927)

Dissection

-

[59]

Scaphechinus mirabilis Agassiz, 1863

Dissection

-

[59]

Scaphechinus tenuis (Yoshiwara, 1898)

Dissection

CASIZ 110668

this study

Sinaechinocyamus mai (Wang, 1984)

Dissection

CASIZ uncatalogued material

this study

Astriclypeidae Stefanini, 1912

Astriclypeus mannii Verrill, 1867

Dissection

-

this study

Echinodiscus auritus Leske, 1778

Dissection

-

[51]

Mellitidae Stefanini, 1912

Encope stokesii Agassiz, 1841

Dissection

CASIZ 3387

this study

Leodia sexiesperforata (Leske, 1778)

Dissection

-

[59]

Mellita quinquiesperforata (Leske, 1778)

Dissection

-

[40, 54, 60, 61], this study

Holasteroida Durham & Melville, 1957

Corystidae Foster & Philip, 1978

Corystus relictus (de Meijere, 1902)

Dissection

ZMK Mortensen collection

this study

Urechinidae Duncan, 1889

Antrechinus nordenskjoldi (Mortensen, 1905)

Dissection

ZMH E7350

this study

Urechinus naresianus Agassiz, 1879

Dissection

NHM 1903.8.1.100-104

[28, 62], this study

Plexechinidae Mooi & David, 1996

Plexechinus aoteanus McKnight, 1974

Dissection

ZMH E7345

this study

Pourtalesiidae Agassiz, 1881

Pourtalesia hispida Agassiz, 1879

Dissection

ZMH E7349

this study

Pourtalesia jeffreysi Wyville Thomson, 1872

MRI (81 μm)³, dissection

ZSM 20011456

[62], this study

Pourtalesia wandeli Mortensen, 1905

MRI (86 μm)³

NHM 1976.7.30.76-95

this study

Spatangoida Agassiz, 1840

Aeropsidae Lambert, 1896

Aeropsis fulva (Agassiz, 1881)

Dissection

CASIZ 113902

this study

Hemiasteridae Clark, 1917

Hemiaster expergitus (Lovén, 1874)

Dissection

NHM 1914.1.30.66-9

this study

Hemiaster hickmanni Koehler, 1914

Dissection

-

[63]

Paleopneustidae Agassiz, 1904

Paleopneustes cristatus Agassiz, 1873

Dissection

-

[64]

Paleopneustes tholoformis Chesher, 1968

Dissection

-

[64]

Prenasteridae Lambert, 1905

Prenaster enodatus (Chesher, 1968)

Dissection

-

[64]

Schizasteridae Lambert, 1905

Abatus cavernosus (Philippi, 1845)

MRI (81 μm)³

ZMB 5854

this study

Abatus cordatus (Verrill, 1876)

Dissection

ZMB 5437

this study

Aceste ovata Agassiz & Clark, 1907

Dissection

-

[63]

Brisaster antarcticus (Döderlein, 1906)

Dissection

AAD uncataloged material

this study

Brisaster fragilis (Duben & Koren, 1846)

Dissection

ZMB 2766

this study

Brisaster latifrons (Agassiz, 1898)

Dissection

-

Sampson (unpublished data)

Hypselaster kempi (Koehler, 1914)

Dissection

-

[63]

Schizaster canaliferus (de Lamarck, 1816)

Dissection

-

[9, 65]

Brissidae Gray, 1855

Brissus agassizii Döderlein, 1885

Dissection

-

this study

Brissus unicolor (Leske, 1778)

Dissection

-

[9, 66]

Meoma ventricosa (Lamarck, 1816)

Dissection

-

[67], this study

Metalia sternalis Lamarck, 1816

Dissection

-

[13]

Brissopsidae Lambert, 1905

Brissopsis alta Mortensen, 1907

Dissection

-

[64]

Brissopsis atlantica Mortensen, 1907

Dissection

-

[64]

Brissopsis elongata Mortensen, 1907

Dissection

-

[64]

Brissopsis lyrifera (Forbes, 1841)

Dissection

ZMB 7259

[9, 64], this study

Brissopsis mediterranea Mortensen, 1913

Dissection

-

[64]

Loveniidae Lambert, 1905

Echinocardium cordatum (Pennant, 1777)

MRI (81 μm)³, dissection

-

[12, 15, 68], this study

Echinocardium flavescens (Müller, 1776)

Dissection

-

[9]

Lovenia subcarinata (Gray, 1845)

Dissection

-

[4]

Spatangidae Gray, 1825

Plethotaenia angularis Chesher, 1968

Dissection

-

[64]

Plethotaenia spatangoides Agassiz, 1883

Dissection

-

[64]

Pseudomaretia alta (Agassiz, 1863)

MRI (81 μm)³

ZSM 20011608

this study

Spatangus purpureus Müller, 1776

MRI (81 μm)³, dissection

ZMB 3236

[8, 9, 17, 66], this study

Maretiidae Lambert, 1905

Maretia planulata (de Lamarck, 1816)

Dissection

-

[4]

Asterostomatidae Pictet, 1857

Elipneustes denudatus (Koehler, 1914)

Dissection

-

[63]

Heterobrissus hemingi (Anderson, 1902)

Dissection

-

[63]

Heterobrissus niasicus (Döderlein, 1901)

Dissection

-

[69]