Acroteriobatus Giltay, 1928

Weigmann, Simon, Ebert, David A. & Séret, Bernard, 2021, Resolution of the Acroteriobatus leucospilus species complex, with a redescription of A. leucospilus (Norman, 1926) and descriptions of two new western Indian Ocean species of Acroteriobatus (Rhinopristiformes, Rhinobatidae), Marine Biodiversity 51, pp. 1-30 : 3-28

Genus Acroteriobatus Giltay, 1928

Type species: Rhinobatus (Syrrhina) annulatus Smith in Müller & Henle, 1841 by subsequent designation

Table 1 Acroteriobatus andysabini sp. nov., morphometrics and meristics

Individual values forthe juvenile maleholotype (SAIAB 97396) and one female paratype (SAIAB 189815), ranges for allother SAIAB and CAS as well as the two larger MNHN paratypes (n = 9), and means and standard deviations (SD) for all nine SAIAB and CAS as well as the two larger MNHN type specimens are presented. Proportional values are expressed as percentages of total length (TL) 70% ethanol preserved except for minimum, maximum, and mean of TL in mm

Table 2 Acroteriobatus stehmanni sp. nov., morphometrics and meristics

Individual values for the adult male holotype (ZMH 25553) and one adult female paratype (ZMH 25557), ranges for all other ZMH paratypes (n = 6), as well as means and standard deviations (SD) for all eight ZMH type specimens are presented. Proportional values are expressed as percentages of total length (TL) 70% ethanol preserved except for minimum, maximum, and mean of TL in mm

Table 3 Acroteriobatus leucospilus , morphometrics and meristics

Individual values for the subadult male syntype (BMNH 1905.6.8.12) and the juvenile male syntype (BMNH 1920.7.23.1), ranges for all examined nontype specimens (n = 9), as well as means and standard deviations (SD) for all 11 examined specimens are presented. Proportional values are expressed as percentages of total length (TL) 70% ethanol preserved except for minimum, maximum, and mean of TL in mm

Key to the 10 valid species of Acroteriobatus

1 Snout dorsally with elongated bluish-gray spots, giving it a stripe-nosed color pattern (6 species) ………................................ 2

- Snout dorsally lacking a stripe-nosed pattern, ventrally plain light to white without a dark blotch (4 species) ............................. 7

2 Snout short and obtusely angled (~88°), disc heart-shapedwith convexanterior margins ……… A. salalah (NW Indian Ocean: Socotra Islands to Pakistan)

- Snout longer and narrowly pointed, disc wedge-shaped with nearly straight to slightly concave anterior margins ...................... 3

3 Snout with only a few, somewhat elongated bluish-gray spots, giving it a very reduced stripe-nosed appearance, maximum size of 622 mm TL …................................................................……… A. stehmanni sp. nov. (NW Indian Ocean: Socotra Islands)

- Snout with pronounced stripe-nosed pattern, maximum size of 750 mm TL or larger ………………..................................... 4

4 Snout with orange stripes between the elongated bluish-gray spots, snout acutely angled at 59–64°, only few bluish-gray spots on disc, tail, and fins; maximum size of 750–790 mm TL ………………...............................................................................… 5

- Snout without orange stripes, snout lessacutely angled at 68–85°, pronounced pattern of bluish-gray spots on disc, tail, and fins; maximum size of 960 mm TL or larger ……………..........................................................................................................…… 6

5 Dorsal surface greenish brown with numerous large dark brown blotches all over the dorsal surface; ventral surface may be covered with small dark spots ………………………………………… A. zanzibarensis (NW Indian Ocean: Zanzibar, Kenya)

- Dorsal surface sandy brown with a strong orangish touch, particularly on snout, and without distinct dark blotches; no specimens withdark ventral spots apart fromunderside of snout known ..........................…… A. variegatus (N Indian Ocean: India, Sri Lanka)

6 Snout angle 79–85°, nasal lamellae 45–48, bluish-gray but no dark brown spots dorsally on central disc, outer edges of pelvicfin margins white, lateral tail folds striped orange and white, ventral snout with black blotches or spots, maturing size above 602 mm TL, maximum size of more than 1000 mm TL ……………… A. andysabini sp. nov. (W Indian Ocean: Madagascar)

- Snout angle 68–81°, nasal lamellae 37–41, no bluish-gray but dark brown spots dorsally oncentral disc, outer edges of pectoral-and pelvic-fin margins blue, lateral tail folds white or striped blue and brown, ventral surface plain white, maturing size of 415–565 mm TL, maximum size of 960 cm TL ………………… A. leucospilus (W Indian Ocean: South Africa to Tanzania)

7 Disc shovel-shaped, snout obtusely angled at ~95°, posterior margin of each spiracle with only one dermal fold …….................................................................................................… A. blochii (SE Atlantic Ocean: South Africa to Namibia)

- Disc wedge-shaped, snout acutelyangled at ~60–70°, eachspiracle with twodermal folds on posterior margin ………................. 8

8 Dorsal surfacebrownish with numerous smallsymmetrically arranged ocelliconsisting of awhite center surroundedby adarker brown rim, snout tip very narrowly pointed, disc narrow (length 1.3–1.4 times width) ........ A. omanensis (NW Indian Ocean: Gulf of Oman)

- Dorsal surface with dark spots or small ocelli, but each ocellus either consisting of a small central dark spot surrounded by a dark-edgedpale ringor with bluish-gray centersurrounded bya dark brown ring, snout tip less narrowly pointed, disc relatively broad (length ~1.1 times width) …………….......................................................................................................……………... 9

9 Dorsal surface light brown with a more or less symmetrical pattern of either dark spots (Natal area) or small ocelli, each consisting of a small central dark spot surrounded by a dark-edged pale ring (South African Cape Province) …….................................................................................… A. annulatus (SE Atlantic and W Indian oceans: South Africa)

- Dorsal surface brownish with numerous irregularly shaped ocelli with bluish-gray centers surrounded by a dark brown rim ……...................................................................................................................… A. ocellatus (SW Indian Ocean: South Africa)