Appendix C. Character descriptions. Morphological matrix of character states can be found in Table Calcified outer shell: (0)




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Appendix C. Character descriptions. Morphological matrix of character states can be found in Table 3.
1. Calcified outer shell: (0) absent; (1) present. A calcified outer shell is no longer present in extant cephalopods except for species within the Nautliloidea.

2. Siphuncle: (0) absent; (1) present (Young and Vecchione, 1996). The presence of a siphuncle is a synapomorphy of all cephalopods (Salvini-Plawen and Steiner, 1996).

3. Inner shell sac: (0) absent; (1) present. All coleoid cephalopods have an internal shell sac, which secretes the internal shell. In the Octopoda sensu Leach (= Incirrata sensu Grimpe) an embryonic shell sac/gland is present during embryonic development, shell material is not always secreted such as in the case of the family Argonautidae (Boletzky, 1982; Naef, 1928).

4. Morphology of inner shell: (0) chambered with siphuncle; (1) uncalcified gladius; (2) uncalcified fin supports; (3) uncalcified stylets. In previous analyses the presence of a phragmocone as well as a separate character for fin supports were considered (Young and Vecchione, 1996). However, due to the variability among coleoid internal shells, separate states have been identified. All character states are included in a single character because the origins of each shell type are likely homologous due to the presence of a shell gland (see character 3). Only those taxa that have a shell sac that secretes shell material are considered. Sepiidae exhibit a chambered internal shell while Spirulidae have an internal, calcified, chambered shell with a siphuncle. The teuthid gladius differs greatly from other internalized shells within the Coleoidea, but is the most common (Toll 1982). While the Octopoda do not have an uncalcified inner shell, stylets are present in many families (with a shell sac in embryonic stage) that is very similar to those present in the Cirroctopoda (gladius modified for fin supports). However, the fin supports in the Cirroctopoda differ greatly from both the gladius as well as the stylets, so a separate character state is provided.

5. Conus morphology: (0) conus absent (1) primary conus present; (2) secondary conus present; (3) pseudoconus present. (Toll, 1982). The primary conus is small and cuplike or sub triangular in outline and exhibits a cone field and a rostrum. The ventral rim forms a broad U- shaped border or is completely transverse. The primary conus is considered homologous to the phragmocone portion of the ancestral shell (Jeletzky, 1966). The secondary conus is a more derived state, formed by ventral curvature and midventral fusion of the posterolateral edges of the vanes (Toll, 1982). Because it is formed from the vanes, the secondary conus is presumed to be derived from the proostracum portion of the ancestral shell and is never found in association with a rostrum. The pseudoconus state occurs when the posterolateral edges of the vanes overlap but no fusion occurs. Conus morphology has been expanded to include all conuses formed by the infolding of the posterolateral edges of the vanes with or without fusion (this state is applicable only to some genera of Cranchiids) (Toll, 1982).

6. One pair of fins: (0) absent; (1) present. At least one pair of fins is present in most cephalopods (Salvini-Plawen and Steiner 1996). The fins are attached to the cartilage-enforced shell epithelium forming an articulated capsule adjacent to the shell sac (Naef, 1921/23).

7. Additional fins (with postembryonic fin developing second and posterior to adult fin): (0) absent; (1) present at some point in life cycle. In decabrachians the fins typically insert on a flattened cartilage (which attaches to the shell sac) with a straight medial ridge. During development a juvenile fin develops first, followed by an adult fin. The juvenile fin is subsequently reabsorbed during growth while the adult fins enlarge (Boletzky, 1982; Naef, 1928). However, in some cases, two sets of fins remain, such as in Vampyroteuthidae (separated by light organs) and some teuthids (although the second fin is often broken off). Within the Teuthida, Chiroteuthidae, Grimpoteuthidae, Batoteuthidae, Joubiniteuthidae, and Mastigoteuthidae all species possess some form of additional fins.

8. Nuchal cartilage: (0) absent; (1) present and exposed; (2) present but not exposed (Young and Vecchione, 1996). The nuchal cartilage supports the head component of the nuchal locking apparatus, the muscles of the collar, head, and shell sac attach to the cartilage. The head of cuttlefishes and squids is well separated from the body by a neck (nuchal construction), believed to be the primitive character state. In some sepiolids the mantle dorsally fuses with the head and is connected by a narrow or wide cutaneous nuchal band (Sepiolinae, Sepiolina, Stoloteuthis, Iridoteuthis, Sepiadariidae). In Idiosepiidae the mantle is not fused with the head, but no nuchal cartilage is present. All remaining squids and cuttlefish have nuchal cartilage connecting the mantle to the head. Nuchal cartilage is present in the Vampyroteuthidae but no longer supports a locking apparatus instead providing a site for muscle attachment. The lack of exposure in Vampyroteuthis is likely to be apomorphic and was therefore coded as a separate state.

9. Chromatophores: (0) absent; (1) present. Chromatophores are vesicular cells that expand due to contractile radiating fibers, found only in coleoid cephalopods (Naef, 1921/23; Salvini-Plawen and Steiner, 1996).

10. Buccal crown: (0) absent; (1) present (Young and Vecchione 1996). The buccal crown consists of muscular buccal supports and connective membranes that surround the lips and mouth. The inner ring of tentacles in Nautilus is homologous to the buccal crown in decabrachians (Naef, 1921/23). In Idiosepius, the buccal crown is apparent in dissected animals, just barely intercalated within the arms of the animal.

11. Buccal membrane connective attachment to arms IV: (0) dorsal; (1) ventral (Roper, 1969; Roper et al., 1969; Young et al., 1998; Young and Harman, 1998). The arms of squids and cuttlefish are attached to the outer membrane surrounding the mouth by a cutaneous and muscular buccal membrane attachment. The major function of the buccal attachment is to hold the arms together in a cone during swimming (Naef, 1921/23). The Vampyroteuthidae, Cirroctopoda and Incirrata have no buccal attachments; the arms are muscular hydrostats. The buccal membrane is attached to the dorsal side of arms I and II, ventral side of arms III, and either dorsal or ventral to arms V.

12. Buccal lappet number: (0) 6; (1) 7; (2) 8 (Roper et al., 1969). The buccal membrane is star shaped, and consists of 6, 7, or 8 rays. Initially 8 lappets are present, though those extending to the first and fourth set of arms may merge together.

13. Beak: (0) absent; (1) present (Salvini-Plawen and Steiner, 1996; Waller, 1998). A beak is present both in the coleoid and nautiloid cephalopods (with calcified additions to the edge in the latter).

14. Radular apparatus: (0) absent; (1) present (Haszprunar, 2000; Salvini-Plawen and Steiner, 1996). While the radula is lost in some molluscs, such as the cirroctopods, a radular apparatus, consisting of a radular sac and odontophore is still present.

15. Circumoral appendages (arms): (0) absent; (1) present (Waller, 1998). The cephalopod head bears an outer circle of at least eight arms that are believed to be derived from the molluscan foot (Naef 1921/23).

Note on arm numbering:

Octobrachia Vamp/Decabrachia

1 I

II

2 III?



3 IV

4 V
Embryological and developmental studies indicate that arms II (rather than arms III) are the pair likely lost by the Octobrachia (Naef 1928). In this case, Arms I, II, III, IV, and V will be used to describe individual arm pairs.

16. Arms II: (0) unmodified; (1) filaments; (2) absent (Young and Vecchione, 1996). Arms II are present in decabrachians, absent in octopods, and modified into filaments in Vampyroteuthis. Early growth stages provide evidence that vampyroteuthid filaments are arms II.

17. Arms IV: (0) unmodified; (1) tentacles (Young and Vecchione, 1996). Modification of Arms IV is one of the significant characters used to separate decapods from octopods. Arms IV are unmodified in octobrachians and vampyromorphs, and modified into tentacles in decabrachians.

18. Horizontal arm septa inserted in the arm muscles: (0) absent; (1) present (Young and Vecchione, 1996). The Cirroctopoda possess a horizontal septum that inserts in the circular muscle layer that forms the outer and thinner portion of the cylindrical muscular wall of the arm; the septum which is orally concave in cross section and divides the muscular tube within each arm into oral and aboral regions. Japetella diaphana was coded as “?” because similar septa are present, they are inserted as two membranes, extending in an oral/aboral plane internal to arm muscles, and it is unclear whether the two states evolved independently. This character was coded directly from Young and Vecchione (1996).

19. Cirri on arms: (0) absent; (1) present (Young and Vecchione, 1996). Cirri are elongate, fleshy, finger-like papillae or palps located along the lateral edges of the oral surface of the arms, particularly in cirrate octopods. The cirri on cirroctopod arms appear may not be homologous to trabeculae found in some decabrachias. Therefore, the presence of cirri is considered an independent character state.

20. Suckers: (0) absent; (1) present (Salvini-Plawen and Steiner, 1996). The suckers of decabrachians are thought to be homologous with the octobrachian form, which is considered the more primitive state (Naef 1921/23).

21. Acetabulum composition lining suckers: (0) cuticular rings; (1) neither cuticular nor horny rings; (2) horny rings (Young and Vecchione 1996). An acetabulum lines the inside of the sucker ring on all coleoids; decabrachians have horny rings, octobrachians exhibit cuticular rings, and vampyromorphs have neither.

22. Sucker stalk: (0) absent; (1) present (Young and Vecchione 1996). Decabrachian suckers are not attached directly to the arm, but connected by a flexible stalk while octobrachian suckers are attached directly to the arm (Naef 1921/23). The suckers of V. infernalis are not attached directly to the arm but do not have “decabrachian-like” stalks and were therefore coded as “?”. This character was modified from Young and Vecchione (1996, character 9) to account for the unknown state of Vampyroteuthis.

23. Sucker symmetry; (0) radial; (1) bilateral (Young and Vecchione, 1996). Decabrachian suckers are bilateral while those of Vampyroteuthis and the Octobrachia exhibit radial symmetry.

24. Armature I-III series: (0) in two rows; (1) in more than two rows; (2) in one row (Young and Vecchione, 1996). Sucker or hook series refers to that in the midarm, not at the tip where numerous rows of suckers can occasionally be observed.

25. Tentacle sucker series: (0) in up to four rows; (1) in greater than four rows. (Roper et al., 1969) Refers to rows of either hooks or suckers on the mid-portion of the tentacle club. This character is only applicable to decabrachians and subsequently coded as n/a in all other taxa.

26. Suckers on buccal membrane: (0) absent; (1) present (Roper, 1969). Small suckers are located on the oral region of the buccal crown in several decabrachian families: Chtenopterygidae, Bathyteuthidae, Loliginidae and Sepiidae. This character is only applicable to decabrachians.

27. Hooks on arms I-III: (0) absent; (1) present (Roper et al., 1969; Young and Harman, 1998). Hooks are modified suckers found on the arms of several decabrachian families.

28. Hooks on tentacles (arms IV); (0) absent; (1) present (Roper et al. 1969; Young and Harman,1998). This character is only applicable to decabrachians.

29. Tentacles (arms IV) in adults: (0) absent; (1) present. This character refers to taxa in which tentacles were present during development but are autotomized prior to or upon maturation. In the case of the Gonatidae, some females autotomize their tentacles during reproduction, however this is not synapomorphic for the family. This character is only applicable to decabrachians.

30. Tentacle locking apparatus: (0) absent; (1) present on carpus only; (2) present on manus and carpus (Young and Harman, 1998). The locking apparatus on the tentacle stalk consists of several suckers with smooth rings and tubercles (knobs) present on the carpal region of the club, which correspond to alternating rings and knobs on the opposite tentacle. The apparatus is applicable only in decabrachians and is highly variable in structure. Young and Harman (1998) used the presence of a tentacle locking apparatus to further investigate the relationships among enoploteuthid-like families.

31. Luminous bacteriogenic, round, bilobed organ located ventrally on ink sac: (0) absent; (1) present (Herring, 1988; McFall-Ngai and Ruby, 1998; Montgomery and McFall-Ngai, 1992). Bacteriogenic light organs are found in two families, the Sepiolidae and Loliginidae (Young, 1977). It is unclear whether the presence of a bacteriogenic light organ is a synapomorphy, therefore only genera within the Sepiolidae are considered here.

32. Luminous autogenic organs with a centrally situated luminous body distributed across mantle and arms: (0) absent; (1) present (Chun, 1914; Herring, 1988). Luminescent organs are found in almost all decabrachians, however they are morphologically and biochemically diverse (Herring, 1988). The presence of light organs across the mantle and arms pertains to one specific family, the Histioteuthidae.

33. Photophores containing collagen light guides: (0) absent; (1) present (1990; Young and Harman, 1998). Collagen light guides are found only in the photophores of the Enoploteuthidae, Lycoteuthidae, and Pyroteuthidae.

34. Funnel: (0) absent; (1) present (Waller, 1998). The presence of a funnel (called hyponome in nautiloids) is a synapomorphy of the Cephalopoda.

35. Funnel: (0) attached to ventral mantle; (1) not attached to ventral mantle; (2) fused to mantle (Young and Vecchione, 1996). Funnel-mantle fusion is present in the Cranchiidae and absent in all other decabrachians. In most octopods, cirroctopods, and V. infernalis the funnel and ventral mantle are attached with a narrow ventral slit present. While the mantle-funnel attachment in the Vampyromorpha is though to be reminiscent of the funnel-mantle locking cartilage of the decabrachians, it was treated as a separate character state.

36. Funnel locking apparatus: (0) absent; (1) present (Roper et al. 1969; Young and Vecchione 1996). Most often, individuals that do not exhibit mantle/funnel attachment possess a funnel locking apparatus. However, there are some cases in which there is no funnel/mantle attachment and no funnel locking apparatus, such as in the cirroctopods.

37. Funnel locking apparatus morphology: (0) simple, straight; (1) triangular, round; (2) inverted T or -| shaped; (3) oval with projecting knobs (Nesis, 1987; Roper et al., 1969). The funnel locking apparatus is a lock and key structure used to keep the mantle from inverting during rapid movement. The morphology varies greatly, particularly among decabrachians. The most common type is the simple, straight found in many oegopsids, sepiolids, and sepiids.

38. Funnel valve; (0) absent; (1) present (Young and Vecchione, 1996). The funnel valve is a one-way muscular flap located on the inner dorsal wall of the funnel.

39. Closed circulatory system: (0) absent; (1) present (Waller, 1998; Haszprunar, 2000). A closed circulatory system is synapomorphic for the cephalopods (Boletzky, 1987; Budelmann et al., 1997).

40. Ink sac: (0) absent; (1) present (Salvini-Plawen and Steiner, 1996). The presence of an ink sac is unique to the cephalopods (although secondarily absent in some octobrachians).

41. Cerebral (pretrochal) eyes: (0) absent; (1) present (Haszprunar, 2000). Synapomorphic character for the Monoplacophora, Scaphopoda, Bivalvia, Gastropoda, and Cephalopoda.

42. Cornea: (0) absent; (1) one-part cornea present; (2) two-part cornea present (Young and Vecchione, 1996). The one-part cornea is the transparent protective outer membrane covering the eye in so-called myopsid cephalopods as well as the Sepiidae and Sepiolidae while all other Decabrachia lack a cornea. Octopods, and cirroctopods have a fully closed, or two-part cornea.

43. Extra-ocular eye muscles: (0) absent; (1) present (Haszprunar and Wanninger, 2000). Extra-ocular eye muscles are autoapomorphic for cephalopods although distinct differences occur between the nautiloids, decabrachians and octobrachians (Budelmann et al., 1997).

44. Paired statocysts: (0) present; (1) absent (Haszprunar and Wanninger, 2000; Salvini-Plawen and Steiner, 1996). In the Mollusca paired statocysts are restricted to the conchiferan classes. Codings taken directly from primary literature sources (Nesis, 1987).

45. Statocyst outer capsule: (0) absent; (1) present (Young and Vecchione, 1996). Coleoid cephalopods have one pair of statocysts situated in the occipital region of the head capsule, which allow for orientation and balance relative to gravitational direction (Nesis, 1987). An outer fluid-filled sac is present in the V. infernalis, octopods and cirroctopods. A single sac embedded in cartilage is present in all other coleoids. Codings for this character were taken directly from Young and Vecchione (1996).

46. Stellate ganglia: (0) absent; (1) present (Salvini-Plawen and Steiner, 1996). Stellate ganglia are present in all cephalopods.

47. Photosensitive vesicles: (0) within cephalic cartilage; (1) above funnel; (2) on stellate ganglia (Young and Vecchione, 1996). Photosensitive vesicles function in the detection of light but vary in location across cephalopods.

48. Inferior frontal lobe system of the brain: (0) absent; (1) partially present; (2) present (Nixon and Young, 2003; Young and Vecchione, 1996). An inferior frontal lobe system is present in the octobrachia.

49. Superior buccal lobe: (0) widely separated from brain; (1) adjacent to brain; (2) fused to brain (Young and Vecchione, 1996). The position of the buccal lobe relative to the supraesophageal mass varies among cephalopods depending on the distance between the buccal mass and brain.

50. Branchial canal: (0) absent; (1) present; (2) secondary reduction of canal (Young and Vecchione, 1996). The branchial canal allows for the passage of seawater between gill lamellae and is present in all coleoids except for the Sepiolidae, Sepiidae, and Spriulidae.

51. Relative position of DGDA: (0) lies in nephridial coel; (1) not in nephridial coel (Young and Vecchione, 1996). Digestive gland duct appendages are present in all coleoid cephalopods although their location is variable.

52. Posterior salivary gland: (0) absent; (1) posterior to brain; (2) proximal to buccal mass (Young and Vecchione 1996). The primitive location of the posterior salivary gland is posterior to the cephalic cartilage, however in Cirroctopoda it is located proximal to the buccal mass.

53. Enlarged coelomic cavity with large amounts of ammonium chloride (0) absent; (1) present. While many cephalopods possess ammonium chloride in their mantle, the family Cranchiidae is the only group to exhibit a modified coelomic cavity to house large amounts of ammonium chloride. This character was coded from primary literature (Denton and Gilpin-Brown, 1973).

54. Ctenidia: (0) absent; (1) present (Giribet and Wheeler, 2002; Haszprunar and Wanninger, 2000; Salvini-Plawen and Steiner, 1996; Waller, 1998). Gills with filaments or leaflets are present in all molluscan classes except for the Scaphopoda and Solenogastres (Giribet and Wheeler, 2002; Reynolds, 2002).

55. Gill lamellae attachment: (0) free; (1) sessile (Young, 1964). Gill lamellae hang free in V. infernalis and decabrachians whereas the lamellae of octopods are sessile. Young (1964) believed that the combination of gill lamellae attachment and branchial canal (character 50) morphology could indicate the primitive nature of the vampyromorph gill.

56. Gill number: (0) one pair; (1) two pairs; (2) more than two pairs (3) single post-torsional left (Haszprunar, 2000). Coleoid cephalopods have a single pair of gills, while Nautilus has two pairs. Other mollusks such as the Polyplacophora have more than two pairs, while some gastropods have a single post-torsional left gill (Hazprunar, 2000).

57. Nidamental glands: (0) absent; (1) present (Young and Vecchione, 1996). Nidamental glands are large, paired organs that are involved in secreting a layer of coating on eggs or egg masses and found in most decabrachians and Nautiloidea.

58. Right oviduct: (0) absent; (1) present (functional or non-functional) (Young and Vecchione, 1996). In coleoid cephalopods a left oviduct is always present, however the right is not. This character was modified from Young and Vecchione (1996, character 30) to consider Idiosepiidae, in which both oviducts are present, but the right is non-functional (Nesis, 1987).

59. Oviducal gland symmetry: (0) radial; (1) bilateral; (2) asymmetrical (Young and Vecchione 1996). The oviducal glands surround the oviducts and provide a layer of coating on eggs or egg masses. Decabrachian oviducal glands are bilateral whereas cirroctopods and octopods exhibit radial symmetry. Vampyroteuthis appears to exhibit neither radial nor bilateral symmetry.

60. Oviducal gland position: (0) gland terminal (located at end of oviduct); (1) gland subterminal (Young and Vecchione 1996). The oviducal glad can be positioned at either the end of the oviduct, (in decabrachians and Nautiloidea) or midway along the oviduct (in octobrachians).

61. Arm I hectocotylization: (0) absent; (1) present. Hectocotylization refers to the modification of one of the arms in male cephalopods for the transfer of sperm to the female (Young and Vecchione, 1996). Hectocotylization can occur on different arm pairs, but is not thought to be homologous and is therefore coded independently. Arms I are hectocotylized only in families Histioteuthidae and Sepiolidae.

62. Arm IV hectocotylization: (0) absent; (1) present (Young and Vecchione, 1996). As the homology of Arms III in octopods and Arms IV in decabrachians is only hypothesized, hectocotylization was coded as present in taxa with an unmodified arm IV (octobrachia).

63. Arm V hectocotylization: (0) absent; (1) present (Young and Vecchione, 1996). Arm V is hectocotylized in several decabrachian families.

64. Yolky, meroblastic egg, with non-spiral cleavage and direct development: (0) absent; (1) present (Boletzky, 2003; Waller, 1998). Most molluscs exhibit spiral cleavage and some form of a larval stage, except for the cephalopods which have direct development and non-spiral cleavage (coded from primary literature, see above).

65. Spermatophores with an ejaculatory apparatus: (0) encapsulated coil; (1) present; (2) absent (modified from Young and Vecchione, 1996). A complex ejaculatory apparatus is present in all coleoid cephalopods except Cirroctopoda, which produce sperm packets. The Nautiloidea and other molluscs lack an ejaculatory apparatus. This character was coded directly from Young and Vecchione (1996).


SPERM CHARACTERS


Sperm morphology has been studied in a wide range of cephalopods (see summary in Healy 1996) such as: Nautilus pompilus (Arnolds and Williams-Arnold, 1978), Vampyroteuthis infernalis (Healy 1989, 1990a), Spirula spirula (Healy 1990a), Opisthoteuthis persephone (Healey, 1993), Eledone cirrhosa (Maxwell, 1974; Ribes et al., 2002), Sepia officinalis (Maxwell, 1975), Loligo forbesi (Maxwell 1975), and Alloteuthis subulata (Maxwell 1975).

66. Acrosomal vesicle: (0) present; (1) absent (Healey, 1990a, 1990b, 1996; Ribes et al., 2002).

67. Large, dense plug within nuclear fossa (=extracellular rod): (0) absent; (1) present (Healy, 1993, 1996). A large, dense plug within the nuclear fossa is shared among Vampyroteuthis infernalis and Octopus spp. According to Healy (1993: 113) “the plug is so distinctive in its ultrastructure that there seems little chance of it having evolved independently in Vampyroteuthis and Octopus.”

68. Curved nucleus: (0) absent; (1) present (Healy 1990b). A curved nucleus is present in Sepiidae, Loliginidae, Rossia (but not Heteroteuthis).

69. Membrane skirt: (0) absent; (1) present (Healy, 1996). A membrane skirt is present in Sepiidae, Loliginidae, and Rossia.

70. Two longitudinal furrows in the nucleus, each accommodating an elongate mitochondrion: (0) absent; (1) present (Healy, 1996). The presence of such a structure is considered autapomorphic for Nautiloidea.

71. Mitochondrial midpiece: (0) absent; (1) present (Healey, 1990a, 1996). Present in all molluscan classes, but not all cephalopods.

72. Mitochondrial spur: (0) absent; (1) present (Healy, 1990a). Mid-piece formation occurs late in spermiogenesis in all cephalopods, however the spur varies morphologically. The mitochondrial spur occurs in Sepiida, Teuthida and Rossia (Healey, 1990a, 1990b; Maxwell, 1975).

73. Periflagellar mitochondrial sleeve: (0) absent; (1) present (Healy, 1990a). A periflagellar mitochondrial sleeve is present in Spirulidae and Heteroteuthis forms the midpiece.

74. Nucleus with eccentrically positioned flagellum: (0) absent; (1) present (Healy, 1996). An eccentrically positioned or offset flagellum is found in Rossia, Loliginidae, and Sepiidae.


OUTGROUP CHARACTERS

Several large-scale molluscan studies were evaluated to determine informative outgroup characters for the Cephalopoda (Giribet and Wheeler, 2002; Haszprunar, 2000; Haszprunar and Wanninger, 2000; Ponder and Lindberg, 1997; Reynolds, 2002; Salvini-Plawen and Steiner, 1996; Waller, 1998; Wanninger and Haszprunar, 2002). Codings for outgroups were taken directly from primary literature sources listed for each character. More detailed descriptions for each character can be found in those sources.

75. Type of outer shell: (0) univalve with one aperture present; (1) univalve with two apertures present; (2) bivalve shell (Giribet and Wheeler, 2002). One aperture is present in gastropods and nautioids, two in scaphopods.

76. Eight external shell plates: (0) absent; (1) present (Giribet and Wheeler, 2002). An autapormophy for the class Polyplacophora.

77. Cuticle with spicules: (0) absent; (1) present (Giribet and Wheeler, 2002). Found in the Caudofoveata, Solenogastres and Polyplacophora.

78. Mantle covering dorsal surface: (0) absent; (1) present (Giribet and Wheeler, 2002; Lee et al., 2003; Salvini-Plawen and Steiner, 1996). The dorsal surface of mantle is covered in Gastropods and Cephalopods.

79. Tubular protochonch: (0) absent; (1) present (Giribet and Wheeler, 2002; Ponder and Lindberg, 1997). The presence of a tubular protoconch is an autapomorphic character for the Gastropoda.

80. Specific head retractor: (0) absent; (1) present (Haszprunar, 2000). The Gastropoda and Cephalopoda exhibit a free head that is retractable by a separate head retractor. Haszprunar described the state in gastropods, limpets in particular as having “a distinct insertion scar of the head retractor” while in cephalopods he called them the anterior pair of the “depressors infundibuli.” In the Scaphopoda, only the buccal cone is free while the cerebral and buccal masses remain fixed.

81. Lateral body compression: (0) absent; (1) present (Giribet and Wheeler, 2002). Bivalvia exhibits a body form that has been laterally compressed.

82. Torsion: (0) absent; (1) present (Giribet and Wheeler, 2002; Ponder and Lindberg, 1997).

83. Operculum: (0) absent; (1) present (Giribet and Wheeler, 2002; Ponder and Lindberg, 1997). An operculum is present in all Gastropoda in the larval stage but is secondarily lost in some adults.

84. Differentiated head: (0) present; (1) absent (Giribet and Wheeler, 2002; Ponder and Lindberg, 1997). A differentiated head is present in all molluscs except for the Bivalvia.

85. Snout: (0) absent; (1) present (Ponder and Lindberg, 1997). This character refers to only those molluscs with a differentiated head (Bivalvia coded as inapplicable), particularly the Gastropoda.

86. Ventral surface of foot: (0) present; (1) absent (Giribet and Wheeler, 2002). The cephalopods are coded as “?” because it is unclear where the ventral surface of the foot is located.

87. Position of anus: (0) opposite oral opening; (1) near mouth opening at ventral side (Haszprunar, 2000). An “ano-pedal flexure” is shared among the Scaphopoda, Gastropoda, and Cephalopoda whereas anterior-posterior axis predominates the rest of the mollusca (Ponder and Lindberg, 1997; Waller, 1998)

88. Cartilagenous cranium: (0) absent; (1) present (Waller, 1998). The cartilaginous cranium is formed to accommodate an extensive fusion of ganglia and is unique to the Cephalopoda.

89. Mantle lobes: (0) absent; (1) present (Giribet and Wheeler, 2002; Salvini-Plawen and Steiner, 1996). Mantle lobes are found only in the Scaphopoda and Bivalvia.

90. Posterior pedal gland: (0) absent; (1) present (Giribet and Wheeler, 2002). All bivalves have a posterior pedal gland in the juvenile state, which is commonly absent in adults.

91. True pedal ganglia: (0) absent; (1) present (Haszprunar, 2000). True pedal ganglia are found in Bivalvia, Scaphopoda, and Cephalopoda whereas elongate, pedal cords are found in the Gastropoda and Polyplacophora.

92. Hydrostatic muscular system: (0) absent; (1) present (Haszprunar, 2000). Gastropods and cephalopods share a “hydrostatic muscular system” (Haszprunar 1988: 405), wherein the extension of body parts occurs via muscle contraction rather than hemolymphatic pressure. Shimek and Steiner (1997) believe the same is true for the dentalid scaphopod foot, which can be extended and utilized rapidly.

93. Adductor muscles: (0) absent; (1) present (Giribet and Wheeler, 2002). Adductor muscles are present in the class Bivalvia.

94. Cephalic tentacles: (0) absent; (1) present (Giribet and Wheeler, 2002; Ponder and Lindberg, 1997; Salvini-Plawen and Steiner, 1996). Cephalic tentacles are likely a synapomorphy for the Gastropoda. Ponder and Lindberg (1997) and Giribet and Wheeler (2002) did not consider the innervated structures of other molluscs as true cephalic tentacles and these were therefore coded as (1) in the present study only for the gastropods.

95. Labial palps: (0) absent; (1) present (Giribet and Wheeler, 2002). Labial palps are present in the class Bivalvia.

96. Kidneys: (0) tubular; (1) sac-shaped; (2) U-shaped (Giribet and Wheeler, 2002). Kidneys are present throughout the Mollusca but vary morphologically.

97. Protonephridia: (0) absent; (1) present (Haszprunar, 2000). The presence of protonephridia in molluscan larvae has previously been established for several molluscans (Bartolomaeus, 1989; Haszprunar, 2000; Haszprunar et al., 2000). However, no such protonephridia have been observed in the cephalopoda (Haszprunar, 2000).

98. True gonoducts: (0) absent; (1) present (Haszprunar, 2000). True gonoducts are present only in the Cephalopoda and Polyplacophora, although a secondary form does occur in the other molluscan classes.

99. Number of coelomoducts: (0) one; (1) two (Haszprunar, 2000). Nautilus is the only mollusc to exhibit two coelomoducts.

100. Captacula: (0) absent; (1) present (Giribet and Wheeler, 2002; Reynolds, 2002). Captacula are retractile feeding tentacles unique to the Scaphopoda.



101. Osphradia: (0) present; (1) absent (Giribet and Wheeler, 2002). Osphradia are present in all molluscan classes except for Scaphopoda and Monoplacophora. Osphradia are absent in coleoid cephalopods. Nautilus possesses osphradia, also referred to as “interbranchial papillae” (Naef 1921/23).





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