Gaza cubana Clench & Aguayo, 1940

Simone, Luiz Ricardo L. & Cunha, Carlo M., 2006, Revision of genera Gaza and Callogaza (Vetigastropoda, Trochidae), with description of a new Brazilian species, Zootaxa 1318 (1), pp. 1-40 : 14-15

Gaza cubana Clench & Aguayo, 1940

( Figs. 20–23 , 53, 54 , 83–88 )

Gaza superba cubana Clench & Aguayo, 1940: 81–82 (pl. 15, fig. 3). Clench & Abbott 1943: 3 (pl. 3, fig. 1–2).

Gaza cubana: Abbott 1974: 49 (fig. 375a).

Types: Holotype MCZ 135151 (examined).

Type locality: CUBA, Santa Ciara , off Sagua la Grande 23º21’N 79º56’W .

Diagnosis: Shell color white iridescent, pale purple on first whorls; surface smooth, glossy, spire about 2/3 of body whorl high; about five whorls. Protoconch without hole in adult. Body whorl with very low, weak spiral lines, almost smooth. Height/width 1.59 on average. Umbilicus about 3/4 covered by callus. Orifices in anterior part of mesopodium: 7 on left, 6 on right side. Number of epipodial tentacles: 5 on right, 6 on left side. Rachidian tooth with squared base, about 1/10 of total radular width; about 20 tall, slender marginal teeth.

Distinctive description

Shell ( Figs. 20–23 ): Shell discoidal; spire low, its height about a half of body whorl height and about half its volume. Protoconch dome­shaped, smooth, glossy, of two whorls ( Figs. 20, 21 ). Spire profile forming flat dome; whorls convex, suture well marked. Body whorl possessing low, blunt carina at periphery. Sculpture similar to that of G. compta , with about 20 spiral lines on penultimate whorl. Spire with first four whorls smooth, gradually spiral lines appearing, becoming more developed on last two whorls; axial sculpture weak, almost absent, more developed in peri­umbilical area. Callus covering about 3/4 of umbilicus ( Figs. 22, 23 ); thin connection with beginning of last whorl; callus edge thicker.

Head­foot ( Figs. 83–85, 88 ): Snout about 1/3 of head­foot width; distal end flat, with numerous almost uniformly sized papillae, slightly larger (50%) at edge, smaller close to mouth. Foot’s anterior orifices: 7 on left, 6 on right side ( Fig. 88 ). Posterior half of epipodium with long, slender epipodial tentacles, 5 on right, 6 on left side ( Fig. 84 ); anterior epipodial tentacle larger, inserted in distal edge; remaining epipodial tentacles up to 3 times shorter, inserted in ventral surface of epipodium. Posterior part of epipodium, surrounding opercular pad, with series of small, papillae rounded at tip ( Fig. 83 : op), separated from each other by distance equivalent to their width, somewhat irregularly sized.

Operculum: Similar to Gaza compta .

Mantle organs ( Figs. 86, 87 ): Gill about same length as pallial cavity. Anterior end of gill pointed. Left gill filaments with about same area as right filaments, both possessing pointed projection oriented towards opposite sides ( Fig. 87 ). Rectum about 1/6 of pallial cavity width, sigmoid, posterior region with loop turned to left surrounding kidney, close to median line abruptly curving anteriorly, gradually towards right up to anus. Anus located about 1/6 of mantle cavity length posterior from mantle border.

Digestive system ( Figs. 85, 86 ): Foregut characters similar to those of G. compta . Radula ( Figs. 53, 54 ) similar to that of G. compta , except by marginal teeth with about 50% wider cutting edge, each marginal tooth with about 12 sub­terminal cusps. Transverse muscles separating anterior region of esophagus from odontophore about 50% shorter, more concentrated in anterior half of esophagus. Internal folds of esophagus possessing similar distributed folds, but taller, more glandular. Rectum about 1/6 of pallial cavity width, weakly looped, with a “U”­shaped loop in its posterior 2/3 into pallial cavity (concavity right).

Measurements of shells (in mm): Holotype = 23.5 x 15.0; UMML 308136, #1, 27.6 x 17.3; #2, 27.2 x 18.7.

Distribution: Gulf of Mexico.

Habitat: About 400 m depth.

Material examined: Holotype. MEXICO; Yucatan; 20º22’N 87º11’W, 434 m depth, UMML 308136 , 2 specimens (Pillsbury 602 col., 16/iii/1967; J.F. Quinn Jr. det.).

Figures

FIGURES 11–23. Gaza spp. Figs. 11–15: G. superba Paralectotype USNM 94992. Figs. 11–13: Shell in apertural, apical and umbilical views. Fig. 14: Detail of umbilical area. Fig. 15: Operculum, outer view. Scale bar = 10 mm. Figs. 16–19: G. daedala Holotype BMNH. Figs. 16–18: Shell in apertural, apical and umbilical views. Fig. 19: Detail of umbilical area. Scale bar = 5 mm. Figs. 20–23: G. cubana Holotype MCZ 135151. Figs. 20–22: Shell in apertural, apical and umbilical views. Fig. 23: Detail of umbilical area. Scale bar = 5 mm.

FIGURES 49–57. Radulae in SEM. Figs. 49–52: Gaza compta. Fig. 49–51: Holotype. Figure 49: entire shell; scale bar = 100 µm. Fig. 50: Detail of central and lateral teeth; scale bar = 50 µm. Fig. 51: Same, detail of marginal region; scale bar = 50 µm. Fig. 52: Paratype, central region; scale bar = 50 µm. Figs. 53–54: G. cubana. Fig. 53: Entire shell; scale bar = 100 µm. Fig. 54: Lateral teeth, scale bar = 100 µm. Figs. 55–57: G. fischeri. Fig. 55: Entire shell, scale bar = 100 µm. Fig. 56: Detail of central and lateral teeth; scale bar = 100 µm. Fig. 57: Detail of lateral region; scale bar = 50 µm.

FIGURES 83–88. Gaza cubana anatomy. Fig. 83: Head­foot, dorsal­slightly right view, operculum removed. Fig. 84: Same, left view. Fig. 85: Head and haemocoel, ventral view, foot and columellar muscle removed. Fig. 86: Pallial cavity hoof and part of mid gut as in situ, ventral view, some adjacent visceral structures also shown. Fig. 87: Gill, transversal section in its middle region. Fig. 88: Foot, head removed, foot anterior orifices (fo) shown. Scale bars = 2 mm.