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Description

Description. Meristic characters are summarised in Table 1 and morphometric characters in Table 2 in comparison with A. sophiae. Twelve of 14 meristic characters are significantly different (p<0.05) for males, although ranges overlap, the characters not significantly different being pelvic fin rays counts and precaudal vertebrae. Nine of 13 meristic characters are significantly different (p<0.05) for females, although ranges overlap, the characters not significantly different being anal and pelvic fin rays counts, gill rakers and precaudal vertebrae. Tests for normality and heteroscedasity show that 8 morphometric characters can be compared between species as ratios with t-tests in females but only one in males. Males are more similar morphometrically than females. The 8 significantly different (p<0.05) characters in females are predorsal length, head depth and prepelvic length, all in standard length, and interorbital width, postorbital length, mouth width and anal fin length, all in head length, and head depth in head length. The sole male character is head width in head length.
Males are more distinct on the PCA (Fig. 2), where meristic and morphometric values are combined, than females (Fig. 3). The first 5 eigenvectors explain over 57% of total variance for males (Table 3) and also for females (Table 4). Discriminant function analyses for males show the variables with the best discriminating power are pectoral fin rays, caudal peduncle length, scales to pelvic fin and postorbital length and for females are pectoral fin rays, scales to dorsal fin, predorsal length and total scales (Table 5).
Description of pigmentation is based on preserved fish only (Fig. 1). Male pigmentation is as follows. The dorsal surface of the head and the upper flank are more heavily pigmented with melanophores than more ventral areas. The belly and lower head are unpigmented. The chin and snout have dense melanophores and a rim of melanophores underscores the eye.
The dorsal, anal and caudal fins in males have wide clear margins. This is also seen in the material from Basrah, Iraq (BM(NH) 1982.9.2:326–328). The caudal fin in the type series of the new species is darker just proximal to the clear margin, lighter in mid-fin and dark again at the base. The dorsal fin has irregular pigmentation on the membranes and, to a lesser extent, on the rays. The pigmentation may involve an overall darker colour in contrast to the light margin or may have some pattern to it. The pattern is often elongate and short blotches with no regular arrangement and sometimes may appear as up to 5 wavy and oblique bands. Dark pigmentation is found just behind the first ray on the fin membrane. The anal fin is darkest just proximal to the clear margin. Up to the last 6 membranes of the anal fin are dark and this pigment may be broken up in as many as 4 elongate bars along each membrane. A similar pattern is found in some dorsal fins and the general effect on both fins is that the postero-dorsal (anal fin) and postero-ventral (dorsal fin) parts of these fins are the darkest. The dorsal, anal and caudal fins generally have more pigment on the membranes than the rays and in some this is quite distinctive, making the rays stand out.
The pectoral and pelvic fins in males are generally clear or somewhat milky and opaque and lack melanophores. The distal parts of the membranes between the last 5 rays of the pectoral fin and the small membrane area of the pelvic fins can be pigmented.
Males have flank bars circling the caudal peduncle and reaching the anal fin base but fading ventrally on the lower part of the anterior flank, not reaching the ventral margin of the belly and becoming progressively shorter and less distinct the more anterior they are. Bars are 2–5 times broader than the pale interspaces.
Females have a similar head and dorsal and ventral body pigmentation but it is much lighter than in males. Fins have little or no pigmentation. The proximal third to half of the dorsal fin rays and membranes, particularly the anterior ones, have pigment in some fish but this is weakly expressed compared to the condition in males. Some fish have a few faint melanophores lining the anal fin rays.
The most distinctive feature in these females is a spot, oval to lozenge-shaped, at the central base of the caudal fin. The spot has the greatest concentration of melanophores of any pigmentation feature.
The flank in females can have up to 14 thin, dark, wavy and irregular vertical patches of pigment. These patches may be interrupted in their vertical extent and are weakly expressed anteriorly. They fade ventrally, ending above the lower edge of the caudal peduncle and above the anal fin base, and are absent on the lower anterior flank. The patches are light and not as contrasting with the lighter interspaces as the bars found in males. Patches are thin, half to one third of the width of the interspaces. Very often the patches are broken up into spots and elongate blotches of various sizes, and a regular barred appearance is not usual. The spots and blotches are all smaller than the eye size by at least half. Material from Basrah, Iraq figured by Berg (1949; Fig. 5 herein) has the spots emphasised but material from Basrah (BM(NH) 1982.9.2:326–328) examined for this study has a more blotchy appearance and spots are not well-defined.

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