Sepia filibrachia Reid & Lu, 2005, n. sp.
Creators: name: Reid, Amanda L.
name: Lu, And Chung-Cheng
Publisher: name: Zenodo
Year: 2005
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Cephalopoda
Sepiida
Sepiidae
Sepia
Sepia filibrachia

description: Sepia filibrachia n. sp. (Figs 17–33, 35; Table 3)
Sepia mestus. — Adam and Rees, 1966: 45 –48 (in part), pl. 13, figs. 74 and 75, pl. 46, fig. 274;
Khromov, 1987: 183–184, fig. 2j–n.
Type material: Holotype. ɗ (47.0 mm ML), mature, TAIWAN: Kaohsiung, Ling Yuan, 22º28´N 120º24´E, 40 m, 7.iii.1998, coll. L.H. Fong (NMNS 4417­001).
Paratypes. TAIWAN: 1ɗ (49.3 mm ML), Mu­Do­Yu, Peng­Hu, 23º44´N 119º35´E, 70 m, 20.x.1996 (NMNS 4417­002); 1ɗ (61.7 mm ML), Peng­Hu, purchased fresh in Ma­ Kung Third Fish Market, 23º33´N 119º33´E, 2.iv.2002, coll. C.W. Ho and W.S. Chung (NMNS 4417­003); 1ɗ (61.2 mm ML), 1Ψ (69.5 mm ML), Peng­Hu, purchased fresh in Ma­Kung Third Fish Market, 23º33´N 119º33´E, 2.iv.2002, coll. C.W. Ho and W.S. Chung (MV F103992); 1ɗ (36.1 mm ML), 2Ψ (44.4, 48.5 mm ML), Ma­Kung, Peng­Hu, 23º34.045´N 119º34.137´E, 4.vi.2002 (NMNS 4417­004); 2Ψ (54.4 mm ML), Wu­chi, Taichung, 24º17´N 120º30´E, 26.iii.1998 (NMNS 4417­005); 1Ψ, 67.6 mm ML, Taichung, purchased fresh in Wu­Chi Harbour Fish Market, 24º17´N 120º30´E, 5.iii.2002, coll. C.C. Lu (NMNS 4417­006).
Additional material: VIETNAM: Gulf of Tonkin: 1ɗ (37.0 mm ML), 1Ψ (46.9 mm ML), Guryanova, 46 m, 7.xii.1961, coll. ‘Pelamida’ (ZIL); 1Ψ (46.5 mm ML), Guryanova, 18º40´N 106º47´E, 55–66 m, 9.i.1961, coll. ‘Pelamida’ (ZIL). TAIWAN: 1ɗ (57.3 mm ML), 2Ψ (65.1, 66.7 mm ML), Miao­Li, 22º29´18.6´´N 120º22´22.7´´E, 50– 40 m, 26.v.2002, coll. N.H. Jang­Liaw (NMNS 4417­007); 1Ψ (36.9 mm ML), 22º51.378´N 120º02.936´E, 104 m, 14.ii.1998, coll. S.C. Fong on ‘Ocean Researcher No. 3’, cruise 411 (NMNS 4417­008); 1Ψ (63.7 mm ML), Peng­Hu, purchased fresh in Ma­Kung Third Fish Market, 23º33´N 119º33´E, 1.iv.2002, coll. C.W. Ho and I.L. Lu (NMNS 4417­009); 1ɗ (54.9 mm ML), 4Ψ (59.5–68.2 mm ML), Peng­Hu, purchased fresh in Ma­Kung Third Fish Market, 23º33´N 119º33´E, 2.iv.2002, coll. C.W. Ho and W.S. Chung (NMNS 4417­ 010); 1ɗ (55.6 mm ML), 1Ψ (47.8 mm ML), Taichung, purchased fresh in Wu­Chi Harbour Fish Market, 24º17´N 120º30´E, 24.vii.2001, coll. M.M. Hsueh (NMNS 4417­011); 1ɗ (51.3 mm ML), Miao­Li, 24º28´36.7´´N 120º21´25.7´´E, depth unknown, 26.v.2002, coll. N.H. Jang­Liaw (NMNS 4417­012); 1ɗ (57.2 mm ML), 3Ψ (53.1–64.5 mm ML), Peng­Hu, purchased fresh in Ma­Kung Third Fish Market, 23º33´N 119º33´E, 7.iv.2001, coll. W.S. Chung (NMNS 4417­013); 1ɗ (50.5 mm ML), 6Ψ (48.0– 62.8 mm ML), Taichung, purchased fresh in Wu­chi Harbour Fish Market, 24º17´N 120º30´E 26.iii.1998, coll. C.T. Wu (NMNS 4417­014).
Diagnosis. Arms 1 and 2 longer than arms 3 and 4 in both sexes; all arms attenuate at distal tips. Arm suckers tetraserial proximally, biserial on extreme distal tips. Hectocotylus absent. Club with four suckers in transverse rows; suckers of inner 2–3 rows slightly larger than rest; dorsal and ventral protective membranes not fused at base of club; dorsal protective membrane longer than ventral protective membrane. Cuttlebone sulcus shallow, wide, flanked by rounded ribs; inner cone limbs not raised to form ledge posteriorly. Paired dorsal eyespots absent.
Description. Small species; ML males 36.1–50.6– 61.7 mm (SD, 8.9); females 46.5– 59.3– 69.5 mm (SD, 8.4). Mantle oval; MWI males 51.2–59.4– 66.2 mm (SD, 4.5); females 52.8–57.5– 62.1 mm (SD, 3.8); dorsal anterior margin triangular, acute; mantle extending to level of posterior margin of eyes; AMHI males 10.2–13.0– 16.6 mm (SD, 1.8); females 11.1–12.7–14.0 mm (SD, 0.9). Ventral mantle margin weakly convex; VMLI males 84.0– 89.0– 93.2 mm (SD, 2.9); females 84.0– 88.7–91.9 mm (SD, 2.4). Fins narrow; FWI males 5.1–9.8– 13.2 mm (SD, 2.2); females 7.4–9.7– 12.4 mm (SD, 1.8); anterior origin posterior to mantle margin; FIIa males 3.3–5.7– 7.3 mm (SD, 1.3); females 2.4–4.1– 5.7 mm (SD, 1.1); rounded posteriorly; with wide gap between; FIIp males 4.5–8.7– 14.4 mm (SD, 3.0); females 4.7–8.3– 15.4 mm (SD 4.0). Funnel short, robust, broad; extends beyond level of anterior rim of eye; FuLI males 26.8–32.9– 38.2 mm (SD, 3.6); females 23.9–30.8– 35.3 mm (SD, 3.5). Funnel free portion approximately one­half funnel length; FFuI males 5.5– 13.6– 17.5 mm (SD, 3.3); females 11.0– 15.4–19.4 mm (SD, 2.8). Funnel organ (Fig. 17) dorsal elements inverted V­shaped with low medial swelling, anterior papilla absent; ventral elements oval with acute anterior tips. Mantle­locking cartilage curved, with semicircular ridge; funnel­locking cartilage with depression that corresponds to ridge (Figs 18, 19). Head short; HLI males 23.5–28.8– 34.9 mm (SD, 3.5); females 19.4–26.1– 33.6 mm (SD, 4.3); broad, narrower than mantle; HWI males 41.5–43.4– 45.4 mm (SD, 1.3); females 31.7–38.9– 43.7 mm (SD, 3.5). Eyes moderate size; EDI males 8.9–12.0– 14.8 mm (SD, 1.9); females 8.4–11.2– 13.4 mm (SD, 1.6); ventral eyelids present.
Arms. Ranges for arm length indices, arm sucker diameter indices and arm sucker counts are shown in Table 3. Male and female arms differ in relative lengths. Male and female arms 1 and 4 slightly longer than rest; arm 4 equal to, or slightly shorter than arm 1; all arms attenuate at distal tips, particularly arms 1 and 2 (Table 3). Protective membranes in both sexes narrow. Arm webs shallow between all arms. Arm sucker arrangement same in both sexes: arms 1–4 suckers tetraserial proximally, biserial on extreme distal tips (most obvious on arms 1 and 2). Chitinous rims of arm suckers with blunt rounded teeth on distal half of inner ring (Fig. 20), teeth absent on proximal half of ring (Fig. 21); infundibulum with 5–6 rows of hexagonal processes, inner 2–4 (variable) rows with elongate rounded pegs, pegs becoming smaller towards periphery of sucker; peripheral sucker rim processes radially arranged, elongate, without pegs. Sucker counts range from 55–148; females with slightly higher average counts than males (Table 3).
Hectocotylus absent.
Tentacular club approximately same length in males and females; ClLI males 9.2– 11.3– 12.8 mm (SD, 1.3); females 10.5–11.3– 12.4 mm (SD, 0.6). Club slightly recurved; short; sucker­bearing face flattened (Fig. 22). Club with four suckers in transverse rows; ClRC males 3–4–4 (SD, 0.3); females 4; 14–16 suckers in longitudinal series; TrRC males 12–16–19 (SD, 2); females 14–17–20 (SD, 2). Suckers differing in size; several suckers of inner 2–3 rows slightly larger than rest (second row from dorsal side with largest suckers). Distal tip of club without pair of slightly larger suckers. ClSI males 0.89–1.07– 1.25 mm (SD, 0.12); females 0.82–0.97– 1.11 mm (SD, 0.13); dorsal and ventral marginal longitudinal series of suckers differing slightly in size; dorsal marginal longitudinal series of suckers slightly larger than those in ventral marginal series; ClSId males 0.38–0.73– 1.09 mm (SD, 0.26); females 0.47–0.57– 0.74 mm (SD, 0.09); ClSIv males 0.26–0.53– 0.83 mm (SD, 0.20); females 0.43–0.47– 0.54 mm (SD, 0.04). Sucker dentition: half inner ring circumference in both sexes with blunt, distally rounded teeth (Fig. 23), remaining half with blunt projections (Fig. 24); infundibulum with five rows of hexagonal processes, innermost with blunt rounded pegs, pegs smaller towards periphery of sucker; at periphery, processes smaller, elongate­rectangular, without pegs (similar to arm suckers). Swimming keel of club extends slightly beyond carpus. Dorsal and ventral protective membranes not fused at base of club; joined to stalk (Fig. 22); dorsal membrane forms shallow cleft at junction with stalk; dorsal and ventral membranes differing in length; dorsal membrane same length as swimming keel, extends beyond carpus along stalk, wider than ventral membrane; ventral membrane terminates at posterior end of carpus.
Males Females Gills with 22–28 lamellae per demibranch; GiLC males 22–23–28 (SD, 1.9); females 24–25–26 (SD, 0.7). Gill length: GiLI males 24–31– 35 mm (SD, 3.0); females 27–31– 36 mm (SD, 3.3).
Digestive tract. Buccal membrane without suckers. Upper beak (Fig. 25) rostrum pointed, short, length approximately equal to width, cutting edge straight; hood high above crest posteriorly; crest curved, lateral wall shallowly indented posteriorly; wings and hood narrow and short; jaw angle slightly less than 90º, slightly acute; hood and crest dark brown. Lower beak (Fig. 26) rostrum protrudes only slightly, cutting edge slightly curved; hood low on crest; crest straight, no indentation on lateral wall edge; lateral wall edge angled posteriorly, not perpendicular to crest; hood and wings, width narrow; hood notch shallow, broad; wings widely spaced; crest narrow; rostrum pigmented dark brown, wings dark brown on inner margin only, rest of wing light brown, crest dark brown. Radula (Fig. 27) teeth homodont; rhachidian teeth with truncate bases, slender, triangular, sides straight; first lateral teeth similar length and width to rhachidian teeth, symmetrical; second laterals longer than first, assymetrical, with mesocone displaced toward centre of radula, distinctly curved on lateral margin, with broad heels; marginal teeth elongate with long tapered and curved mesocone. Digestive tract: (not illustrated) as for Sepia mestus.
Male reproductive tract (Fig. 28). Testis on left posterior side of viscero­pericardial coelom; at distal end, convoluted vas deferens opens into broad, cone­shaped mucilaginous gland, then narrower, curved, spermatophoric gland. Close to junction with lobeshaped accessory gland and gland appendix, delicate ciliated canal joins spermatophoric gland; distal deferent canal connects appendix of accessory gland to spermatophore storage sac; genital orifice opens dorsal to left gill in anterior end of mantle cavity. Spermatophores (Figs 29, 30): cement body bipartite; aboral end elongate barrel­shaped, truncate posteriorly, connects to sperm reservoir via narrow duct; oral end of cement body elongate, pear­shaped, approximately three­quarters length of, and very slightly narrower than aboral end, connects to aboral end via short neck; middle tunic commences along aboral part of cement body; ejaculatory apparatus coiled, extends into oral dilation of spermatophore. Spermatophores 2.7–3.3–4.0 mm long (SD, 0.6); 0.1–0.2– 0.3 mm wide (SD, 0); SpLI 5.8–6.8– 7.5 mm (SD, 0.8); SpWI 4.7–5.6– 6.7 mm (SD, 0.7).
Female reproductive tract. Ovary hangs from dorsal wall of posterior viscero­pericardial coelom. Oviduct thin­walled, continuous with body cavity; distally with thickened, glandular walls (oviducal glands). Nidamental glands in mature animals occupy large portion of ventral side of mantle cavity. Accessory nidamental glands anterior to nidamental glands. Eggs spherical; 2.7–3.8– 5.2 mm diameter (SD, 1.0); EgDI 5.5–6.8– 9.2 mm (SD, 1.7). Buccal membrane in females without spermathecae.
Cuttlebone (Figs 31–33). Cuttlebone length approximately equal to mantle length. Subdermal cartilaginous layer between cuttlebone and skin absent. Cuttlebone calcified. Phragmocone equal in length to dorsal shield. Cuttlebone outline oval; CbL males 35.7– 50.9– 62.2 mm (SD, 8.7); females 44.7–58.3– 68.8 mm (SD, 8.8); CbWI males 39.1–41.8– 44.0 mm (SD, 1.6); females 40.8–42.8– 46.1 mm (SD, 1.5); not strongly convex in lateral view; CbBI males 9.5–10.6– 12.6 mm (SD, 0.9); females 10.7–12.2– 13.8 mm (SD, 1.1). Bone acuminate, acute anteriorly; bluntly rounded posteriorly; not strongly recurved ventrally. Dorsal surface creamy white; evenly convex; calcified with very fine reticulate sculpture; posterior end of bone not covered with smooth glaze­like substance. Dorsal median rib absent; lateral ribs absent; dorsal median groove absent. Very narrow rim of chitin surrounds entire margin of cuttlebone. Spine present; short, pointed; straight; SLI males 4.2–6.5– 8.5 mm (SD, 1.4); females 3.6–5.5– 7.5 mm (SD, 1.3); directed dorsally; with ventral keel; cuttlebone smooth between spine and outer cone; ventral notch at base of spine absent. Dorso­posterior end of cuttlebone without median longitudinal ridge anterior to spine. Striated zone flat, or very slightly concave; extends laterally to inner cone; not separated from outer cone by smooth marginal zones; StZI males 54.0– 64.3–71.5 mm (SD, 6.6); females 52.9–67.8– 76.3 mm (SD, 7.4). Last loculus flat; LoLI males 20.4– 27.4– 39.8 mm (SD, 7.1); females 17.7–26.3– 41.3 mm (SD, 7.0); approximately half as long as striated zone; LoLI/StZI(%) males 28.5–44.2– 73.8 mm (SD, 16.5); females 23.2– 40.3–78.0 mm (SD, 16.5). Sulcus extends along striated zone only; shallow, wide (sometimes with deeper narrow median furrow); flanked by rounded ribs. Last loculus with shallow median indentation, not very pronounced. Anterior striae slightly convex to straight, or blunt inverted V­shape. Limbs of inner cone extend anteriorly to end of striated zone; inner cone lateral limbs not separated from outer cone by two distinct smooth zones. Inner cone limbs narrow anteriorly, broaden posteriorly; not raised to form ledge posteriorly; only outer margin slightly thickened, shiny; without calcareous ribs radiating into outer cone. Outer cone present; calcified; wide; narrow anteriorly, broadens posteriorly; lateral limbs flared ventro­laterally; limbs forming thin rim ventral to spine.
Papillae and pigmentation. Body papillae present; dorsal mantle covered with numerous small papillae, or with series of elongate papillae along each side, close to base of each fin (irregular). Ventral mantle with scattered papillae at base of fins; head papillae absent. Arm papillae absent. Ground colour (alcohol preserved specimens) dark brown; arms without markings. Dorsal mantle chromatophores concentrated medially over cuttlebone. Paired dorsal eye spots absent; fins pale. Fins without markings at base. Ventral pigment present, pale.
Remarks. The specimens from the Gulf of Tonkin are clearly misidentified as S. mestus, differing from that species in a number of characters. Sepia filibrachia is a small species, ranging up to 69.5 mm ML, while S. mestus attains sizes up to 124 mm ML. The arms of S. mestus are subequal in length and are not attenuated distally; those of S. filibrachia differ in their relative lengths, with arms 1 and 4 longer than the remaining arms. In all but one specimen examined, arm 1 is longer than arm 4. The distal arm tips are attenuated in S. filibrachia, with biserial suckers at their tips, while the arms are short and robust and suckers are all tetraserial in S. mestus. The relative arm lengths are much greater in S. filibrachia than in S. mestus (compare Tables 2 and 3). The club has 5–6 suckers in transverse rows in S. mestus, and only 4 in S. filibrachia. The relative sizes of these suckers differ to a greater degree in S. filibrachia than they do in S. mestus (compare Figs 5 and 22). The club protective membranes are joined at the base of the club in S. mestus and separate in this species. The spermatophores of the two species differ: the primary difference is seen in the cement body, which is bipartate in S. filibrachia, but not so in S. mestus. With respect to the cuttlebone, the striae are less arched in S. filibrachia than they are in S. mestus, and the sulcus, while absent in S. mestus, is distinct in S. filibrachia and flanked by rounded ribs that give the striae a wavy appearance (compare Figs 15 and 32, 33). Sepia filibrachia lack the dorsal eyespots and ventral wrinked skin pads that are seen in S. mestus. Sepia filibrachia is similar to S. grahami Reid, 2001, particularly in the form of the cuttlebone, which is almost indistinguishable in the two species. The arms of S. grahami are subequal in length and not attenuate, while in S. filibrachia the arm lengths differ as described above and are attenaute distally. Sepia grahami has tetraserial suckers only, while those at the arm tips are biserial in S. filibrachia. The club swimming keel extends well beyond the carpus in S. grahami, and only slightly beyond it in S. filibrachia. The shape of the oral portion of the cement body is cylindrical in S. grahami and pear­shaped in S. filibrachia. The cuttlebone sulcus is narrow and not flanked by rounded ribs in S. grahami, and the striae are an inverted U­shape, while in S. filibrachia the sulcus is wide, flanked by rounded ribs and the striae are slightly convex to straight, or a blunt inverted Vshape. A pair of dorsal eyespots is present in S. grahami, but not seen in S. filibrachia.
Distribution (Fig. 35). Taiwan, Mu­Do­Yu, 23º44´N 119º35´E, Peng­Hu and Wu­chi, Taichung 24º17´N 120º30´E. South China Sea, Hainan Island, Haikou. 20º40´N 107º56´E; 18º40´N 106º47´E; 11º25´N 109º15´E. Vietnam, Gulf of Tonkin, Guryanova. Depth range 34–95 m (live animals).
Etymology. The specific name is derived from the Latin filum, meaning ‘thread’, or ‘string’, and brachium, ‘arm’ and refers to the nature of the arms in this species. Gender feminine.
description: Published as part of Reid, Amanda L. & Lu, And Chung-Cheng, 2005, with a redescription of Sepia mestus Gray, 1849 (Cephalopoda: Sepiidae) from eastern Australia, pp. 1-22 in Zootaxa 911 on pages 13-21, DOI: 10.5281/zenodo.171017