ILLUSTRATED KEY TO THE FAMILIES OF OCTOCORALLIA

by

Gary C. Williams

California Academy of Sciences

 

ORDER HELIOPORACEA

2 FAMILIES

ORDER PENNATULACEA

14 FAMILIES

ORDER
ALCYONACEA

30 FAMILIES

TOTAL

46 FAMILIES OF OCTOCORALS

 

Couplet Number

Description

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1A

Rigid skeleton of pure crystalline aragonite (Helioporacea)

2

1B

Skeletal components absent or if present then composed predominantly of calcite and/or gorgonin

3

2A

Massive skeleton formed of fused corallites, powder blue in color. Sclerites absent

HELIOPORIDAE

2B

Polyps retractile within rigid cylindrical calyces of nonspicular crystalline aragonite. Polyps with calcitic sclerites

LITHOTELESTIDAE

3A

Colonies with a basal muscular peduncle for anchoring in soft substrata. Polyps trimorphic or quadrimorphic; oozooid present (Pennatulacea)

4

3B

Colonies without a basal peduncle. Polyps monomorphic or dimorphic, oozooid absent (Alcyonacea)

18

4A

Adjacent polyps free, not fused to any degree

5

4B

Proximal portions of adjacent autozooids fused to some degree, forming polyp leaves or raised ridges, or joined only at the bases

15

5A

Colonies cordate/foliate; rachis greatly flattened, lying on surface of substratum

RENILLIDAE

5B

Colonies cylindrical, capitate, clavate, or elongate; rachis erect, not lying on substratum

6

6A

Autozooids distributed evenly on all sides of rachis, or proximal portion of rachis with a single longitudinal furrow or V-shaped region devoid of polyps

7

6B

Autozooids confined to a terminal cluster, or arranged biserially along rachis, or in whorls of two to four arranged sparsely along rachis, or arranged on three sides of rachis with a naked dorsal tract along entire length of rachis

8

7A

Siphonozooids without calyces

VERETILLIDAE

7B

Siphonozooids with conspicuously bifurcated, spiculated calyces

ECHINOPTILIDAE

8A

Autozooids arranged in a terminal cluster at the end of a long slender stalk

UMBELLULIDAE

8B

Autozooids arranged along the sides of the rachis

9

9A

Colonies cylindrical or clavate with distal portion somewhat wider than rest of colony. Polyps arranged biserially and individually (not in oblique rows), or disposed on three sides of rachis with a naked dorsal tract along the entire length of the rachis

KOPHOBELEMNIDAE

9B

Colonies elongated and narrow with uniform thickness, or if clavate then polyps arranged in oblique rows. Polyps arranged biserially or in isolated pairs or whorls

10

10A

Colonies without sclerites. Polyps arranged biserially without calyces

ANTHOPTILIDAE

10B

Colonies with or without sclerites, and polyps arranged in pairs or whorls of 2-4, without calyces

11

11A

Rachis with or without sclerites Polyps arranged in pairs or whorls of 2-4, without calyces

12

11B

Rachis with sclerites. Polyps arranged biserially, with calyces

13

12A

Rachis with spindles or rods (<0.10 mm)

SCLEROPTILIDAE

12B

Rachis without sclerites or with minute irregularly-shaped rods (>0.05 mm)

CHUNELLIDAE

13A

Autozooids tubular with calyces having eight conspicuous terminal teeth; siphonozooids and autozooids morphologically similar

FUNICULINIDAE

13B

Calyces with zero to eight terminal teeth. Siphonozooids and autozoods very different morphologically

14

14A

Polyps arranged in oblique or transverse rows along the rachis. Colonies often somewhat clavate

STACHYPTILIDAE

14B

Autozooids arranged in one to three longitudinal rows along the rachis; colonies elongate, not clavate

PROTOPTILIDAE

15A

Autozooids disposed on raised ridges or pads that are obliquely arranged along the rachis

16

15B

Autozooids disposed on conspicuous polyp leaves that emanate laterally along the rachis in two opposite longitudinal series

17

16A

Rachis with sclerites. Polyps with bifurcated, spiculiferous calyces

HALIPTERIDAE

16B

Rachis without sclerites. Polyps without calyces

ANTHOPTILIDAE

17A

Polyp leaf sclerites reduced (ovals and plates) or absent. Siphonozooids few and sparsely distributed

VIRGULARIIDAE

17B

Polyp leaf sclerites are numerous and conspicuous (spindles and needles). Siphonozooids numerous to congested and densely-set

PENNATULIDAE

18A

Permanently solitary octocorals composed of a single large polyp

TAIAROIDAE

18B

Colonial octocorals; polyps multiple, produced by vegetative budding

19

19A

Polyps separate, joined only at the proximal bases by stolons or multilayered platforms

20

19B

Polyps partly united laterally or contained in a common coenenchyme

23

20A

Calcareous skeleton absent

CORNULARIIDAE

20B

Calcareous skeletal elements present

21

21A

Colonies with stolons forming rigid multi-layered platforms above the substratum

TUBIPORIDAE

21B

Colonies arborescent with a reduced stolon, or colonies with conspicuous stolons not forming rigid multi-layered platforms

22

22A

Colonial growth form richly arborescent. Polyps non-retractile, calyces absent

COELOGORGIIDAE

22B

Colonies composed of retractile polyps with cylindrical, conical, or mound-like calyces

CLAVULARIIDAE

23A

Colonies composed of one elongated axial polyp with many short lateral polyps (autozooids) embedded in the thick coenenchyme of the axial polyp wall

PSEUDOGORGIIDAE

23B

Single dominant axial polyp lacking; smaller polyps in dimorphic taxa are siphonozooids, not autozooids

24

24A

Coenenchyme not differentiated into outer and inner layers. Gastric cavities of polyps extend throughout height of colony

25

24B

Coenenchyme differentiated into outer and inner layers (cortex and medulla), or internal calcareous and/or proteinaceous axis present

29

25A

Sclerites composed of anhedral rods or nodules

XENIIDAE

25B

Sclerites of composed of subhedral or euhedral crystals

26

26A

Polyparium composed of branches or clusters of polyps, which is retractile into a common basal stalk or trunk

PARALCYONIIDAE

26B

Polyparium, if composed of branches or clusters of polyps, not retractile into common basal stalk or trunk. If polyparium is retractile, then not composed of branches or clusters of polyps

27

27A

Polyps often grouped in clusters or restricted to branch tips of the polypary

NEPHTHEIDAE

27B

Polyps evenly distributed on the surface of the polypary

28

28A

Colonies with a rigid consistency, outer surface rough, containing large tuberculate sclerites, longitudinally placed. Polyps retractile into mostly prominent calyces

NIDALIIDAE

28B

Colonies usually fleshy, sclerites generally not in the form of longitudinally disposed large spindles. Calyces absent except in a few species

ALCYONIIDAE

29A

Coenenchyme differentiated into an outer cortex and an inner medulla. Medulla composed entirely of free but densely set sclerites

30

29B

Colony with axial support composed of inseparably fused sclerites, or sclerites united by horny proteinaceous material (gorgonin) and/or CaCO3, or entirely proteinaceous and permeated by varying amounts of non-spicular CaCO3, or totally calcified without sclerites or horn

33

30A

Colonies dimorphic

PARAGORGIIDAE

30B

Colonies monomorphic

31

31A

Cortex and medulla separated by a ring of longitudinal boundary canals

32

31B

Cortex and medulla not separated by a ring of longitudinal boundary canals

BRIAREIDAE

32A

Sclerites of the medulla are mostly smooth and curved, partly fused to form a network

SUBERGORGIIDAE

32B

Sclerites of the medulla include tuberculate or somewhat branched rods or spindles

ANTHOTHELIDAE

33A

Axis jointed (segmented); with alternating nodes and internodes

34

33B

Axis not jointed; continuous and uniform, without alternating nodes and internodes

36

34A

Axis with sclerites

35

34B

Axis without sclerites

ISIDIDAE

35A

Branches arise from proteinaceous nodes

MELITHAEIDAE

35B

Branches arise from calcareous internodes

PARISIDIDAE

36A

Polyps dimorphic

CORALLIIDAE

36B

Polyps monomorphic

37

37A

Central axis proteinaceous with ridges and grooves, the ridges are spiny resembling the stem of a black coral or rosebush

DENDROBRACHIIDAE

37B

Central axis smooth or longitudinally grooved, but not with conspicuous spiny ridges

38

38A

Central axis with hollow, cross-chambered core (Suborder Holaxonia)

39

38B

Central axis with solid core (Suborder Calcaxonia)

42

39A

Chambered core of axis surrounded by smooth sclerites bound together by sheaths of horn-like material

KEROEIDIDAE

39B

Chambered core of axis surrounded by horn-like layers that may contain non-spicular calcareous material

40

40A

Polyps non-retractile. Polyps covered in spindles that often forming chevrons

ACANTHOGORGIIDAE

40B

Polyps retractile. Polyps without sclerites that form chevrons

41

41A

Polyps usually with sclerites comprising some form of crown and points. Sclerites >0.3 mm in length

PLEXAURIDAE

41B

Polyps without sclerites or with small rodlike bodies. Sclerites <0.3 mm in length

GORGONIIDAE

42A

Sclerites include many double heads

ELLISELLIDAE

42B

No double heads are present

43

43A

Colonies zooxanthellate, in shallow water (<50 m). Sclerites are irregularly shaped ovals, rodlets, and crosses (<0.1 mm in length)

IFALUKELLIDAE

43B

Colonies azooxanthellate, in deeper water (mostly >50 m). Sclerites are mostly derived from scales (>0.1 mm in length)

44

44A

Surface of axis longitudinally grooved, usually gray to black, sometimes with a metallic luster

PRIMNOIDAE

44B

Surface of axis smooth, not grooved, with a metallic luster of greenish, bronze, or gold

CHRYSOGORGIIDAE