Microphis nicoleae, Haÿ & Mennesson & Lord & Keith, 2023

MICROPHIS NICOLEAE SP. NOV.

( TABLE 4; FIGS 9–11)

ZOOBANK REGISTRATION: urn:lsid:zoobank. o r g: a c t: C B C 4 7 8 F D - 3 A 8 D - 4 0 B 3 - A 1 A D - D76AFA9B688F

Material examined

Holotype: MNHN-IC-2019-0082 (tag 19193), male, 110.72 mm SL. Vage River , Kolombangara ( Solomon Islands), 18 Nov. 2015, Keith et al. coll.

Paratypes: MNHN-IC-2021-0336 (tag 14961, 14962, 14963), 3 females, size range 64.27–83.69 mm SL. Ovana River, Ranongga ( Solomon Islands), 25 Oct. 2016, Keith coll. MNHN-IC-2021-0337 (tag 19199), female, 67.52 mm SL. Liva River , Kolombangara ( Solomon Islands), 11 Nov. 2015, Keith et al. coll. MNHN-IC-2021-338 (tag 17692, 17693), 2 males, size range 93.66–104.79 mm SL. Hoskin River , New Britain ( Papua New Guinea), 27 Oct. 2018, Keith et al. coll. MNHN-IC-2021-0339 (tag 19071), male, 105.26 mm SL. Ou River , New Britain ( Papua New Guinea), 29 Oct. 2018, Keith et al. coll. MNHN-IC-2021-0340 (tag 19171, 19173, 19174, 19175), 1 male and 3 females, size range 73.43–93.45 mm SL. Gavuvu River , New Britain ( Papua New Guinea), 27 Oct. 2018, Keith et al. coll .

Diagnosis: Microphis nicoleae differs from its congeners by the following combination of morphological characters: 16–19 pectoral fin rays, 36–38 dorsal fin rays, 28–30 tail rings and 7.5–9.5 subdorsal tail rings.

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

The body is smooth, tapered and covered in dermal plates forming a series of rings. Dorsal fin rays 33 (34– 38). Caudal fin rays nine. Pectoral fin rays 16 (16–19). Trunk rings 16 (16), tail rings 30 (28–30). Subdorsal trunk rings one (0.5–1.5), subdorsal tail rings seven (7.0–8.5) and total subdorsal rings eight (7.5–9.5). Anal fin is atrophied and located just after the urogenital papilla. Pelvic fins absent. Head length (10 to 12% of SL); short (inferior or equal to 5% of SL) and thin snout (inferior or equal to 2% of SL). The snout shape does not differ from the other congeners, M. retzii and M. torrentius . Size up to 110.7 mm SL.

Operculum with a complete longitudinal ridge with supplemental ridges below the longitudinal ridge ( Fig. 11A). Pectoral-fin base with a complete distinct ridge ( Fig. 11A). Two distinct superimposed lateral snout ridges from the head of the mouth to the end of the eye ( Fig. 11A). Discontinuous supraorbital ridge from the naris to the near end of the operculum ( Fig. 11A, B). Complete supraopercular ridge over the entire length of the operculum ( Fig. 11A). Discontinuous ridge on the head from the mouth to the middle of the second trunk ring ( Fig. 11B). Scutella keeled on the side of the tail and often keeled on the side of the trunk ( Fig. 11C). 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. 11C). 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 located under trunk with pouch plates slightly convergent and pouch folds absent; begins on the first trunk ring and ends at the urogenital papilla. Eggs are small, deposited in a single layer of three to four rows with about a hundred eggs per pouch.

Colour in preservation:. Male and female body brownish and, in general, the coloration appears darker on the back than on the belly. Some specimens may show white vertical stripes along the body. Some specimens may show a dark stripe on the side of the snout and the operculum. Caudal fin brownish, while other fins are translucent.