Schindleria qizma, Ahnelt & Macek & Robitzch, 2023

Ahnelt, Harald, Macek, Oliver & Robitzch, Vanessa, 2023, A new species of Schindleria (Teleostei: Gobiiformes: Gobiidae) from the Red Sea (Saudi Arabia) with a specialized caudal-fin complex, Vertebrate Zoology 73, pp. 313-323 : 313

Schindleria qizma sp. nov.

Figures 2 , 3 , 4 , 5 , 6 , 7

Holotype.

NMW 99999. Female, 10.6 mm SL, north Al Fahal reef, sheltered side, north-central Red Sea, Thuwal, Saudi Arabia, 19th February 2015, V. Robitzch.

Paratypes.

NMW 10000. Female, 10.7 mm SL, 22nd February 2015 and NMW 100001. Female, ~10.9 mm SL, 17th June 2015 2015. Otherwise, same data as the holotype.

Diagnosis.

A member of the SDF group of Schindleria , which can be distinguished from all members of the LDF group by a combination of following characters: (i) the dorsal fin about the same or nearly the same length of the anal fin (vs. dorsal fin distinctly longer than anal fin), (ii) a relatively short (5.8 % of SL vs. 8.7% of SL) and deep (2.2% of SL vs. 1.5% of SL) caudal peduncle, (iii) a straight (vs. flexed) urostyle, fewer procurrent rays (0-2 vs. 5-8), and absence of teeth in both jaws (vs. both jaws with teeth).

From the four other species of the SDF group (i.e., S. brevipinguis , S. edentata , S. parva and S. pietschmanni ), S. qizma can be distinguished as follows: (i) anal-fin rays (11 vs. 10 in S. brevipinguis , 13 in S. edentata , 9 in S. parva and 14-17 in S. pietschmanni ), (ii) a shorter preanal-fin length (60.2% of SL vs. 71.4% in S. brevipinguis , 64.8% in S. edentata , 71.8% in S. parva and 65.6% in S. pietschmanni ), (iii) a shorter head (12.4% of SL vs. 14.3% in S. brevipinguis , 14.9% in S. edentata and 19.1% in S. parva ), (iv) a shorter snout (18.6% of head length vs. 25.0% in S. brevipinguis , 23.1% in S. edentata and ~29% in S. parva ), (v) a shorter tail (excluding caudal fin) (its length 32.6% in SL vs. 39.4% in S. brevipinguis , 36.2% in S. edentata and 39.4% - 49.2% in S. pietschmanni ) (vi) a larger eye (35.3% of head length vs. 33.3% S. brevipinguis , 27.7% in S. edentata and ~23% in S. parva ), (vii) a straight, unflexed urostyle, dorsally enclosed by the hypural cartilage (vs. posterior tip flexed, hook-like, attached to the anterior, upper-edge of the hypural cartilage), (viii) head depth ± increasing continuously (vs. increasing steeply [except S. pietschmanni ]) and (ix) an urogenital papilla with two long, flat, and bilobed projections in females (vs. an urogenital papilla without such projections).

Schindleria qizma can be further distinguished from S. pietschmanni by (i) number of dorsal fin rays (13 vs. 15-19), (ii) toothless jaws (vs. jaws with numerous tiny teeth), (iii) deeper body (body depth at anus 8.2%-9.6% SL vs. 5.5%), (iv) a deeper head (53.4% in head length vs. 34.3 %), (v) a short urostyle (3.6% of SL vs. 5.8% of SL), (vi) fewer procurrent rays (0-2 vs. 6-7), (vii) smaller adult size (<13mm TL vs.>17 mm TL) and (viii) females with few (11 vs.>40), very large (3.5 - 4.6% SL vs. 1.2% - 1.8% SL) eggs vs. more (in total) and smaller () eggs.

Schindleria qizma can be further distinguished from S. parva by (i) toothless jaws (vs. premaxillary with many tiny teeth), (ii) a shorter predorsal-fin length (59.4% of SL vs. 63.6% of SL), (iii) more dorsal-fin rays (13 vs. 9-10), (iv) more anal-fin rays (11 vs. 7-9), and (v) females with few eggs (11 vs. 60).

Schindleria qizma can be further distinguished from S. brevipinguis by (i) a shorter predorsal-fin length (59.4% SL vs. 64.3% SL), (ii) a shorter preanal length (54% SL vs. 61.2% SL), (iii) a shallower body (5.9% SL at pectoral-fin base vs. 9.3% SL, 7.6% SL at base of 4th anal-fin ray vs. 11.5% SL), (iv) a narrower (51.9% head length vs. 57%) and shallower head (53.4% head length vs. 59.6%), (v) mouth cleft oblique (vs. nearly vertical), (vi) a narrower interorbital width (25.4% head length vs. 35.2%), (vii) a shorter tail (32.6% SL vs. 39.4%), (viii) a deeper caudal peduncle (35.6% caudal peduncle length vs. 25%), and (ix) a shorter urostyle (3.6% SL vs. 6.3%).

Schindleria qizma can be further distinguished from S. edentata by (i) fewer dorsal-fin rays (13 vs. 15) and (ii) fewer anal-fin rays (11 vs. 13), (ii) a shorter tail (32.6% SL vs. 36.2%), (iii) the shape of the postabdominal region (continuously decreasing in depth vs. evenly deep in anterior half but rapidly decreasing in depth in posterior half), (iv) a shallower body at base of 4th anal-fin ray (7.6% SL vs. 10.9%), (v) a greater eye diameter (35.6% head length vs. 27.7%, 139.3% interorbital width vs. 111.1%), (vi) a narrower interorbital width (25.4% head length vs. 30.8%), (ii) larger maximum width of pectoral radial plate (76.8% pectoral radial plate length vs. 36.4%), (viii) a deeper caudal peduncle (35.6% of caudal peduncle length vs. 25.6%), and (ix) a shorter urostyle (3.6% SL vs. 5.8% SL).

Description.

Morphometric (Table 1 ) and meristic information (Table 2 ) is given separately for the holotype and the paratypes. Body slender, elongate, somewhat compressed; body depth increases only very slightly from head to anus; head short and oval in lateral view, with head profile gradually rising posteriorly (Fig. 3A ); snout short and rounded; jaws short and posteriorly just reach a vertical line through the anterior quarter of orbit; lower jaw only slightly projecting; mouth somewhat superior; no teeth on premaxilla or on dentary (Fig. 4 ); premaxilla long, thin with shallow, indistinct post-maxillary process; maxilla also long, thin, anteriorly hook-like and only slightly widened distally; postabdominal region distinctly shorter than abdomen region, ends in an elongated, relatively short caudal peduncle (Fig. 2 ); urostyle conical, relatively short, just about length of last 2 1/2 caudal vertebrae; tip of urostyle not flexed but straight, ends in middle of cartilage of hypural plate (Figs 5 , 6 ); hypural plate large, triangular; externally, the preserved body without pigmented except for black eyes; all three females have few (10-11) but very large (3.5% - 4.6% of SL) eggs (Fig. 2 ) in the abdominal cavity, arranged in two rows anteriorly, but just a single row posteriorly.

If different, values for paratypes are given in parentheses: first dorsal fin and pelvic fin absent; dorsal-fin rays 13; anal-fin rays 11; principle caudal-fin rays 7+6=13, all segmented once, none branched; caudal fin truncated; procurrent rays 1 (0-1) dorsal and 2 (0-1) ventral, when present short, with no additional spine (Fig. 6 ); base of first dorsal-fin ray at myomere 21, that of last dorsal-fin ray at myomere 34; base of first anal-fin ray at myomere 22 and that of last at myomere 34; 37 myomeres total, 21 precaudal and 16 caudal; 38 total vertebrae (including urostyle), with 22 precaudal and 16 caudal; 5 branchiostegal rays; a relatively wide pectoral-radial plate, of paddle-like shape, distally only slightly wider than at its origin; gut straight; female urogenital papilla conspicuous, slightly bulbous with opening flanked by two long, flat, bilobed projections (Fig. 7 ); swim bladder small, oval-shaped, inconspicuous, pigmented dorsally, located at myomeres 14/15, in posterior half of abdomen (Fig. 2 ).

Coloration in life.

Unknown.

Coloration preserved.

The entire body, including the head, is uniformly whitish. The iris of the eye is black and capped dorsally with an iridescent silvery layer spotted with numerous melanophores (Fig. 3 ). The black pigment cap on the swim bladder is visible through the body wall (Fig. 2 ). The fins are translucent.

Distribution.

Schindleria qizma is so far only known from Al Fahal reef in the north-central Red Sea, Thuwal, Saudi Arabia, 22°18 ’24.54” N, 38°57 ’47.25” E (Fig. 1 ).

Etymology.

The name ‘qizma’ comes from the Arabic word ‘qizm’ (مزق), which means dwarf. It is a noun in apposition and refers to the very small size of the species.

Figures

Figure 1. Published records of Schindleria in the Red Sea: star = S. qizma n. sp., in Thuwal; filled circle = S. elongata, S. nigropunctata (Fricke & Abu El-Regal, 2017 a, b), S. praematura (Abu El-Regal and Kon, 2019), and S. edentata (Ahnelt et al., 2022), all in Hurghada; black square = Schindleria sp. (Al-Solami and Abu El-Regal, 2020) and S. parva (Abu El-Regal et al., 2021), both in Jeddah; empty circle = Schindleria sp., in Thuwal (Robitzch et al., 2021). The map is from https: // www. landkartenindex. de / kostenlos / cliparts / cliparts _ gruppe _ 1 / saudiarabien. gif.

Figure 2. Holotype of Schindleria qizma (NMW 99999), female, 10.6 mm SL; Thuwal, Saudi Arabia. Same specimen shown in reflected (white) and transmitted light (dark). Arrows indicate position of swim bladder. Scale bar = 1 mm.

Figure 3. Paratype of Schindleria qizma (NMW 100000), female, 10.7 mm SL; Thuwal, Saudi Arabia. A head in lateral view. B head in dorsal view. Scale bar = 0.5 mm.

Figure 4. Head of Schindleria qizma, paratype (NMW 100000), 10.7 mm SL, lateral view. Note toothless jaws. DEN = dentary; MX = maxilla; PMX = premaxilla. Scale bar = 0.1 mm.

Figure 5. Comparison of caudal-fin skeleton in Schindleria. A Schindleria qizma (NMW 100000), paratype, 10.7 mm SL, preserved in ethanol, not stained: urostyle straight and ending inside hypural plate. B Schindleria sp. (uncatalogued), 16.9 mm SL, preserved in ethanol, stained with cephalopod ink. C Schindleria sp. (CAS 38797), 17.7 mm SL, cleared (muscles were digested) and stained with Alcian blue; procurrent rays not shown. B, C flexed urostyle, hook-like tip fused to hypural plate. HPU = haemal spines of preural vertebrae; hy = hypural plate; NPU = neural spines of preural vertebrae; pu 2 and pu 3 = second and third preural vertebra; ur = urostyle; 1 - 6 = procurrent rays, last ray elongated. Scale bar = 0.5 mm.

Figure 6. Caudal-fin skeleton in Schindleria qizma; A holotype (NMW 99999), 10.6 mm SL; B paratype (NMW 100001), ~ 10.9 mm SL; C paratype (NMW 100000), 10.7 mm SL. hy = hypural plate; ur = urostyle, straight and inserted into hypural plate. Each arrow indicates a procurrent ray; asterisk = no procurrent ray developed. Scale = 0.5 mm.

Figure 7. Comparison of urogenital region in Schindleria females. A Schindleria qizma (NMW 99999), holotype, 10.7 mm SL; asterisks indicate paired bilobed projections on left and right side of urogenital opening; arrow indicates urogenital opening covered by mucus. B Schindleria qizma, (NMW 100000), paratype, 10.7 mm SL. C Schindleria praematura (NMW 86241), 18.5 mm SL; urogenital papilla with two short, hornlike projections. A 1 = first anal-fin ray; UG = urogenital papilla; a = anterior; v = ventral. Scale = 0.5 mm.