Iridoteuthis Naef, 1912

Reid, Amanda L., 2021, Two new species of Iridoteuthis (Cephalopoda: Sepiolidae: Heteroteuthinae) from the southwest Pacific, with a redescription of Stoloteuthis maoria (Dell, 1959), Zootaxa 5005 (4), pp. 503-537: 504-505

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Iridoteuthis Naef, 1912


Genus Iridoteuthis Naef, 1912  

Type species. Stoloteuthis iris Berry, 1909   , type locality Hawaiian Islands , off Molokai I   .

Diagnosis (after Harman & Seki, 1990; Young & Vecchione, 2007; this study). Ventral shield present;>80%

VML. Mantle-head fusion wide. Body very deep dorso-ventrally, with pronounced convex mid-dorsal arch. Posterior fin lobe angled posteriorly, elbow-shaped. Distal free portion of funnel swollen dorsally. Funnel-locking apparatus a curved groove and deep angular pit; mantle-locking cartilage elbow-shaped. Visceral photophore round, convex, with pair of protruding, cylindrical photophore tubes positioned anteriorly on each side. Webs extend slightly beyond halfway along arms, except 4 th pair. Arms 3 with prominent aboral keel, or ‘flag’. Arms 4 with a greater number of suckers than remaining arms in both sexes. Distal tip of club recurved and joined to tentacle stalk. Tentacle organ extends along sucker-bearing face of the club from beyond sucker-bearing portion of club to recurved distal tip. Club suckers smaller distally than proximally. Club sucker outer ring plates uniform width, without distinct ‘pegs’. Females with fleshy bursa copulatrix on left side.

definitions are indicated by an asterisk (*). OBL and VSL follow measurement introduced in Fernández-Álvarez et al.

(2021). Indices (I) (shown in square brackets) are calculated by expressing each measure as a percentage of mantle length.

For paired structures, such as arms, unless left (L), or right (R) is specifically designated, the structure in the best condi-

tion of the pair was measured.

Arm Length— AL: length of each designated (i.e. 1, 2, 3, 4) arm [L, left; R, right] measured from first basal (proximal-most)

sucker to distal tip of [ALI].

Arm Sucker Count *— ASC: total number of suckers on each designated arm (e.g. ASC2).

Arm Sucker diameter— AS: diameter of largest sucker on each designated (i.e. 1, 2 etc.) arm [ASIn].

Club Length— ClL: length of tentacular club measured from proximal-most basal suckers (carpus) to distal tip of club [ClLI].

Club Row Count— ClRC: number of suckers in transverse rows on tentacular club.

Club Sucker diameter— ClS: diameter of largest sucker on tentacular club [ClSI].

Egg Diameter— EgD: diameter of largest egg present in the ovary or oviduct [EgDI].

Eye Diameter— ED: diameter of eye orbit [EDI].

Fin Insertion— FI: length of fin as joined to mantle [FII].

Fin Insertion anterior *— FIa: anterior origin of fin measured from mantle margin to anterior-most junction of fin and mantle [FIIa].

Fin Width— FW: greatest width of single fin [FWI].

Free Funnel length— FFu: the length of the funnel from the anterior funnel opening to the point of its dorsal attachment to the head [FFuI].

Funnel Length— FuL: the length of the funnel from the anterior funnel opening to the posterior margin measured along the ventral midline [FuLI].

Gill Lamellae Count— GiLC: number of gill lamellae per demibranch, excluding the terminal lamella.

Gill Length *— GiL: length of the gill [GiLI].

Head Length— HL: dorsal length of head measured from point of fusion of dorsal arms to middle of occipital band [HLI].

Head Width— HW: greatest width of head at level of eyes [HWI].

Mantle Length— ML: dorsal mantle length. Measured from middle of occipital band to posterior apex of mantle.

Mantle Width— MW: greatest straight-line ventral width of mantle [MWI].

Occipital Band Length *— OBL: length of band of integument joining anterio-dorsal mantle to head, measured over dorsal convex ‘hump’ [OBLI].

Spermatophore Length— SpL: length of spermatophore [SpLI].

Spermatophore Width— SpW: maximum width of spermatophore [SpWI].

Ventral Mantle Length *— VML: length of mantle measured along ventral midline [VMLI].

Ventral Shield Length *— VSL: length of ventral shield measured along ventral midline [VSLI].