Microphis vaillantii, (JUILLERAT, 1880)

MICROPHIS VAILLANTII (JUILLERAT, 1880) View in CoL

( TABLE 4; FIGS 4–6)

Material examined

Holotype: MNHN-IC-A-2359, male, 121.3 mm SL. Madagascar.

Others: MNHN-IC-2022-0150 (tag R12 ), female, 95.5 mm SL, Roches Beauvallon , Reunion Island, 18 Jan. 2021, Valade et al. coll. MNHN-IC-2022-0151 (tag R14 , R16 , R18 , R20 , R21 , R22 , R24 , R26 , R27 ), 6 females, 3 males, 93.7–119.5 mm SL, Roches Beauvallon, Reunion Island, 19 Oct. 2021, Valade et al. coll .

Diagnosis: The species has a head length of 10 to 12% of SL and 33–34 tail rings.

Description: Morphomeristic data is given in Table 4. Holotype counts are given first, followed in brackets, by other specimens counts.

The body is smooth, tapered and covered in dermal plates forming a series of rings. Dorsal fin rays 60 (55– 60). Caudal fin rays nine. Pectoral fin rays 19 (17–19). Trunk rings 17 (17), tail rings 34 (33–34). Subdorsal trunk rings 4.5 (3.5–4.5), subdorsal tail rings 8.5

G

O PfB

G

(8.0–8.5) and total subdorsal rings 13 (12–13). Anal fin is atrophied and located near the urogenital papilla. Pelvic fins absent. Head length (10 to 12% of SL); short (inferior or equal to 5% of SL) and thin snout (equal to 1% of SL). Size up to 121.3 mm SL.

Operculum without ridge and pectoral-fin base without distinct ridge. Scutella not keeled. Absence of lateral snout ridge ( Fig. 5A). Absence of supraopercular ridge ( Fig. 5A). One supraorbital ridge from the naris to the middle of the eye ( Fig. 5A, B). Discontinuous ridge on the head from the mouth to the middle of the eye and to the middle of the head to the middle of the first trunk ring ( Fig. 5B). Pattern of lateral trunk and tail ridges, superior trunk and tail ridges are discontinuous with lateral trunk ridge confluent with the inferior tail ridge under the dorsal fin ( Fig. 5C). The section of trunk V-shaped, while section of tail is square-like. There is a sexual dimorphism, with a brood pouch for males. Brood pouch is located under trunk with pouch plates slightly convergent and pouch folds are absent; begins on the first trunk ring and ends at the urogenital papilla. Eggs are small, deposited in a single layer of four to five rows with about a hundred eggs per pouch.

Colour in preservation: Male and female body are greyish. The operculum has an iridescent appearance. Usually with a dark lateral stripe, above the lateral trunk ridge, from the tip of the snout to the beginning of the tail. Scutella on the tail are circled with a black stripe. Caudal fin brownish to black, while other fins are translucent.