Schindleria edentata, Ahnelt & Robitzch & El-Regal, 2022

Ahnelt, Harald, Robitzch, Vanessa & El-Regal, Mohamed Abu, 2022, A new species of toothless, short dorsal-fin Schindleria (Gobiiformes: Gobiidae) from the Red Sea (Egypt), Vertebrate Zoology 72, pp. 551-559 : 551

Schindleria edentata sp. nov.

Figures 1 , 2

Schindleria sp. Abu El-Regal & Kon (2008).

Schindleria sp. Fricke & Abu El-Regal (2017a, b).

Schindleria sp. Abu El-Regal & Kon (2019).

Holotype.

BMNH 2007.5.20.1. Male, 9.0 mm SL. Red Sea, Egypt, Hurghada, reef lagoon, 27.285°N, 33.772778°E. 05 February 2005, M. Abu El-Regal.

Diagnosis. A member of the SDF group of Schindleria , which can be distinguished from all members of the LDF group by the combination of following characters (i) length of dorsal fin nearly equal to that of anal fin (vs. dorsal fin significantly longer than anal fin); (ii) body deeper (10.8% in SL vs. 4.5-5.4% in SL); (iii) body depth significantly increasing from pectoral-fin base to 4th anal-fin ray (vs. not or only slightly increasing); (iv) head short and wide with steep profile (vs. elongated and narrow with flat profile) and (v) both jaws toothless (vs. both jaws with teeth).

From the other species of the SDF group, Schindleria edentata can be distinguished as follows 15 dorsal-fin rays (vs. 9-13 in S. parva and S. brevipinguis , 16-18 in S. pietschmanni ), 13 anal-fin rays (vs. 7-11 in S. parva and S. brevipinguis , 19-21 in S. Schindleria pietschmanni ), preanal-fin length 64.8 % SL (vs. 72% in S. parva , 66.7% in S. brevipinguis , 54% in S. Schindleria pietschmanni ), predorsal-fin length 60.9% SL (vs. 65.0% in S. parva , 63.0% in S. brevipinguis , 58.3% in S. pietschmanni ); length of tail excluding caudal fin 36.2% SL (vs. 28.2% in S. parva , 39.4% in S. brevipinguis , 42.1% in S. pietschmanni ), length of urogenital papilla 4.8% SL (vs. 3.0% in S. parva , 7.6% in S. brevipinguis and <0.5% in S. pietschmanni ), eye diameter 27.7% HL vs. 20.0% in S. parva , 31.1% in S. brevipinguis , 23.1% in S. pietschmanni ), mouth terminal (vs. superior in S. parva , S. pietschmanni , S. brevipinguis ).

Schindleria edentata can be further distinguished from S. brevipinguis and S. pietschmanni by a wider head (35.9% HL vs. 55.7% in S. brevipinguis , 43.2% in S. pietschmanni ) and a lower number of caudal procurrent rays (4/4 vs. 6/6 in S. brevipinguis and S. pietschmanni ).

Schindleria edentata can be further distinguished from S. parva and S. pietschmanni by its toothless jaws (vs. upper jaw toothed in S. parva both jaws toothed in S. pietschmanni ), and head shape (stubby, oval with steep profile vs. elongated, narrow with flat profile in S. parva and S. pietschmanni ).

Schindleria edentata can be further distinguished from S. parva by fewer myomeres (36 vs. 39), the first dorsal-fin inserted at myomere 21 (vs. myomere 24), the first anal-fin ray at myomere 23 (vs. myomere 26) and a greater body depth at pectoral-fin base (7.3% SL vs. 5%).

Schindleria edentata can be further distinguished from S. brevipinguis by a shorter caudal peduncle (8.2% SL vs. 11.5%), pectoral-radial plate longer than wide (vs. nearly as long as wide) and a pigmented swim bladder (vs. unpigmented swim-bladder).

Description.

Morphometric information for the holotype is given in Table 1 and meristic data in Table 2 . Body elongate, increases gradually in depth from about myomere 8 to about middle of tail, rapidly decreasing in depth to end in long narrow caudal peduncle, length ca. 25% of SL); head oval with steep profile; snout short, rounded; jaws short, reaching below origin of eye; lower jaw curved towards midline (Fig. 2 ).

First dorsal fin and pelvic fin absent; dorsal-fin rays 15; anal-fin rays 13; pectoral-fin rays 14; principle caudal-fin rays 7+6=13; caudal fin truncated; procurrent rays 4 dorsal and 4 ventral; procurrent rays gradually increasing in length, last procurrent ray simple, with no additional spine, not distinctly elongated; base of first dorsal-fin ray at myomere 21, that of last dorsal-fin ray at myomere 35; base of first anal-fin ray at myomere 22, that of last anal-fin ray at myomere 35; total number of myomeres 36 with 21 abdominal and 15 caudal; vertebrae 37,with 21 abdominal and 16 caudal (incl. urostyle); Branchiostegal rays 5; pectoral-radial plate longer than wide, of paddle-like shape, narrow at origin and wide distally; gut straight; male urogenital papilla elongated, tubular, tapering towards posteriorly curved tip, tip without distinct lobes at opening; swim bladder small, inconspicuous, pigmented dorsally, located at myomere 13, in posterior half of abdomen,.

Coloration in life.

Transparent; the only pigment is a melanophore cap on top of the swim bladder and the black pigmentation of the eye (see also Abu El-Regal and Kon 2008).

Coloration preserved.

Due to subsequent preservation artifacts, the entire specimen is now dark brown to blackish (Fig. 1A ).

Distribution.

Schindleria edentata is only known from a shallow (7 m) reef lagoon near Hurghada (Egypt), Red Sea (27.285°N, 33.772778°E) (Fig. 3 ).

Habitat.

The bottom of the lagoon was sandy and covered with algae and seagrass. The specimen was sampled at a depth of 1 m.

Etymology.

The name Schindleria edentata , derived from the Latin e = without, and dentatus = toothed, refers to the absence of teeth in both jaws, an adjective.

Figures

Figure 1. A Holotype of Schindleria edentata (BMNH 2007.5.20.1), male, SL 9.0 mm; Egypt, Hurghada. Arrows indicate position of broken-off first and second dorsal fin rays. Scale bar = 1 mm. Photo H. Ahnelt. B Same specimen, but photo taken shortly after initial collection. Grey arrow indicates position of last dorsal fin ray, black arrow indicates position of swim bladder. Scale = 1 mm. Photo M. Abu El-Regal.

Figure 2. Holotype of Schindleria edentata (BMNH 2007.5.20.1), male, SL 9.0 mm; head in lateral view. Scale bar = 0.2 mm. Photo H. Ahnelt.

Figure 3. Records of Schindleria in the Red Sea. Circle = S. elongata, S. nigropunctata, Hurghada (Fricke & Abu El-Regal, 2017 a, b) and S. praematura, Hurghada (Abu El-Regal and Kon 2019); black star = sampling site of S. edentata nov. spec., Hurghada; black dot = Schindleria sp., Thuwal (Robitzch et al. 2021); black square = S. parva, Jeddah (Abu El-Regal et al. 2021); empty square = Schindleria sp., Jeddah (Al-Solami and Abu El-Regal 2020). Map is based on https: // www. landkartenindex. de / kostenlos / cliparts / cliparts _ gruppe _ 1 / saudiarabien. gif