A new species of Sicyopterus (Teleostei: Gobioidei: Sicydiinae) from Papua New Guinea Author Lord, Clara Author Keith, Philippe Author Causse, Romain Author Amick, Peter text Cybium 2020 44 2 127 136 http://dx.doi.org/10.26028/cybium/2020-442-004 journal article 284896 10.26028/cybium/2020-442-004 07444398-4c39-4364-b689-d5c23dfcc690 2101-0315 10493488 Sicyopterus elomionearum n. sp. ( Figs 2-5 , Tabs II-V) Diagnosis A Sicyopterus with 3 clefts (one anteriorly and 2 midlaterally) on upper lip, with smooth lip and with a second dorsal fin with 1 spine and 10 segmented rays. Courting male coal black with a pearl white necklace. 63-69 scales in lateral series, 27-33 in transverse forward and 21-23 in transverse back series. Table II. – Scale counts in Sicyopterus n. sp. and related species

Lateral series
48	49	50	51	52	53	54	55	56	57 58	59	60	61	62	63	64	65	66	67	68	69
S. sarasini	1	1	2	1	– 1	2	4	2	4	4	3	1
S. erythropterus	2	– 1 1 (males)			1	2	1 1 (females)
S. japonicus	1	1	1	1	1
S. parvei	1	1 –	1
S. nsp	2	2	2	–	3	–	1

Predorsal midline series
0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19 20		21 22		23 24		25	26	27	30	31	32	//40
S. sarasini	2	1	–	1	1	1	–	–	2	2	–	3	1	4	–	2	2	1	–	1
S. erythropterus	1	–	–	1	–	–	–	– – – (males)					1	–	1	–	–	1	1	–	– – – 1 (females)				–	2
S. japonicus	1	1	–	1	–	–	2
S. parvei	1	1	–	1
S. nsp	1	–	–	1	–	–	5	–	2	//1

Transverse backward series
14	15 16		17	18	19	20	21 22		23
S. sarasini	2	5	11	9
S. erythropterus	3	3	–	2	–	1
S. japonicus	1	2	1	1
S. parvei	1	–	–	2
S. nsp	7	2	1

Transverse forward series
14	15	16	17	18	19	20 21		22	23	24	25	26 27		28	29	30	31	32	33
S. sarasini	1	1	–	–	–	–	1	–	1	1	2	4	7	4	4	–	–	1
S. erythropterus	1	1	1	2	2	1	1
S. japonicus	3	2
S. parvei	1	2
S. nsp	2	5	–	1	–	1	1

Zigzag series
12	13	14	15	16	17	18	19
S. sarasini	1	2	9	12	1
S. erythropterus	1	3	3	2
S. japonicus	1	2	–	2
S. parvei	1	1	1
S. nsp	3	7

Table III. – Diagnostic morphometrics in Sicyopterus n. sp. and related species expressed to the nearest whole percent of standard length.

Head length
20	21	22	23 24		25	26 27		28	29	30
S. sarasini	1	6	8	6	4
S. erythropterus	3	5	1
S. japonicus	1	–	–	4
S. parvei	2	–	–	1
S. nsp	1	1	3	1	1	1	2

Preanal length
49	50	51	52	53	54	55	56	57	58	59	60	61	62
S. sarasini	3	1	3	4	5	4	2	–	–	2	1
S. erythropterus	2	1	–	1	3	–	1
S. japonicus	1	–	1	1	2
S. parvei	1	1	1
S. nsp	2	3	1	3	–	–	–	1

Table IV. – Fin lengths in males of Sicyopterus n. sp. and related species expressed to the nearest whole percent of standard length.

Second dorsal fin length
27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48	49	50	51	52	53	54	55	56	57	58
S. sarasini	1	1	1	–	1	–	–	2	–	1	1	3	3	1	2	–	–	1
S. erythropterus	1	–	1	1	1	–	–	1
S. japonicus	1	–	–	–	–	–	1
S. parvei	1	–	1
S. nsp	1	1	1	1	–	1	–	–	1	–	–	–	–	1

Anal fin length
25	26	27	28	29	30	31	32	33	34	35	36 37		38	39	40	41	42	43	44	45
S. sarasini	1	–	1	1	2	1	2	1	3	2	1	1	1
S. erythropterus	1	1	2	–	1
S. japonicus	2
S. parvei	1	–	–	–	–	1
S. nsp	1	–	–	1	1	–	–	–	–	1	–	1

Table V. – Fin lengths in females of Sicyopterus n. sp. and related species expressed to the nearest whole percent of standard length.

Second dorsal fin length
24	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48	49	50
S. sarasini	1	–	1	1	–	–	1	1	1	2
S. erythropterus	1	1	–	–	–	–	1	1
S. japonicus	1	–	–	–	1	1
S. parvei	1
S. nsp	1	–	1	–	–	–	–	–	1

Anal fin length
23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40
S. sarasini	1	–	1	–	–	2	–	1	1	1	1
S. erythropterus	1	–	–	1	2
S. japonicus	1	–	–	–	–	–	–	–	–	1	–	1
S. parvei
S. nsp	1	–	–	–	1	–	–	1

Figure 3. – Diagrammatic illustration of urogenital papilla in Sicyopterus elomionearum n. sp. (ventral view): 1. anus; 2. urogenital papilla; 3. anal fin. A : Male; B : Female. Figure 2. – Diagrammatic illustration of head in Sicyopterus elomionearum n. sp. showing cephalic sensory pore system and cutaneous sensory papillae. A : Dorsal view; B : Lateral view; C : Ventral view. Known and described from 10 specimens from streams of West New Britain , Papua New Guinea , totalling 6 males and 2 females , size range 23.6-82.2 mm SL. Material examined Holotype . – MNHN 2019-0107 (tag MP-10634), male, 69.4 mm SL. Elnge Creek , New Britain ( Papua New Guinea ), 12 Nov. 2015 , Amick et al . coll. Paratypes . – MNHN 2019-0108 (tags MP-12801, MP-12802), 1 male , 1 female , size range 41.8-43.7 mm SL. Bereme village , Huvenganga River , 19 Oct. 2018 , Keith et al. coll. MNHN 2019-0109 (tag MP-17822, MP-17824, MP-17825, MP-17601, MP-17603), 4 males , 1 female , size range 23.6-27.1 mm SL. Bereme village , Galuku River , 20 Oct. 2018 , Keith et al. coll. MNHN 2019-0110 (tags MP-10565, MP-10570), 1 male , 82.2 mm SL, 1 female , 81.9 mm SL. Same data as holotype, Amick et al. coll . Description Scale counts are given in table II, morphometrics in table III and fin length in tables IV and V. Below, the holotype counts are given first, followed in brackets, if different, by the paratypes’ counts. Dorsal fins VI-I,10; the first dorsal fin has the third and fourth rays slightly filamentous, usually reaching to one third of the length of the second dorsal fin base in males, with the third ray longer; not reaching the second dorsal fin in females. Anal fin I,10 directly opposite to the second dorsal fin. Caudal fin with 15-16 branched rays and posterior margin rounded. Pelvic disk with 1 spine and 5 branched rays on each side, fifth rays joined together over their entire length, a strong frenum between spines, disc adherent to belly between all 5 rays. Pectoral fins usually 19-21, posterior margin rounded. LS 67 (63-69), PD scales 40 (22-32). Small cycloid scales on head, nape, flanks; belly entirely covered with cycloid scales, extending from anus, almost to pelvic fin base. Well-developed ctenoid scales on the rest of the body. TRB 23 (21-22). TRF 33 (27-32). ZZ 19 (18-19). Upper jaw with a single row of flexible tricuspid teeth (60-97), lateral cusps rounded, medial cusps shorter than lateral cusps and sharply pointed. Dentary with a single straight row of conical teeth 12 (2-8) on each side, not curved and not meeting at symphysis; anterior and posterior teeth usually caniniform; horizontal teeth correspond in position with upper jaw teeth. Upper lip smooth with 3 clefts (one anteriorly and 2 midlaterally). Lower lip mostly absent, rudimentary elements present as expanded and folded tissue posterior to lower jaw teeth. Cephalic sensory pore system A, B, C, D, F, H, L, M, and N. Pore O absent. Pore D singular with all others paired. Oculoscapular canal uninterrupted posterior to eye. Cutaneous sensory papillae present on head ( Fig. 2 ). Males with triangular urogenital papilla with distal tip rounded. Females with bulbous urogenital papilla with fimbriate projections around distal opening ( Fig. 3 ). Figure 4. – S i c y o p t e r u s e l o m i onearum, Paratypes , MNHN 2019-0108. A : Female, SL 41.8 mm ; B : Male, SL 43.7 mm . Bereme village, Huvenganga River, West New Britain Island, Papua New Guinea, 19 Oct. 2018 , Keith et al. coll. Figure 5. – Sicyopterus elomionearum , Holotype, MNHN 2019-0107 (tag 10634), male, 69.4 mm SL. Elnge Creek, New Britain (Papua New Guinea), 12 Nov. 2015, Amick et al . coll. Figure 6. – Photos of the type locality of the paratype specimens of Sicyopterus elomionearum . A : Huvenganga River, West New Britain Island, Papua New Guinea (Paratypes, MNHN 2019-0108); B : Galuku River, West New Britain Island, Papua New Guinea (Paratypes, MNHN 2019-0109). Colour in preservation Female and male body uniformly greyish to brownish ( Fig. 4 ). Throat, pelvic fins and belly white. The pectoral fins are dark grey. The first and second dorsal fins are a translucent grey. Caudal fin grey. Anal fin translucent with a black margin. Black tear under the eye. Males develop specific colours during courtship: body entirely dark brown with lighter brown pectoral and caudal fins. Two dorsal and anal fins black. Head dark brown from snout to preoperculum. Nape, operculum, throat and pelvic disc white, as if male was wearing a necklace. Colour in life Body dusky grey with 3 to 4 Y-shaped lighter grey marking along the sides. Belly white to greyish. Dorsal fins hyaline to translucent. Pectoral fins brown. Caudal fin greyish to brownish. Anal fin hyaline with black margin. Head dark and usually with a black tear under the eye. There is a sexual dichromatism; males in courtship are coal black, with black dorsal and anal fins. Pectoral fin base black becoming brownish on the edge. Caudal peduncle black with whitish markings on caudal fin. Operculum, throat, pelvic sucker, and sometimes nape, pearly white, as if male was wearing a necklace ( Fig. 5 ). Ecology Paratype specimens were caught in small streams in the vicinity of Bereme village, West New Britain Island. The streams were narrow (about 3 m wide), well imbedded in the tropical rainforest with tall trees and native vegetation keeping the stream in the shade. The habitat consists of clear, well-oxygenated water, running through large boulders on a gravel and sand bottom ( Fig. 6 ). The current was slow to moderately fast; temperature and pH values of 24.4-25°C and 8, respectively were recorded. Distribution Sicyopterus elomionearum n. sp. is currently known only from several streams in West New Britain Island, Papua New Guinea (Elnge Creek, Huvenganga River, Galuku River and their tributaries). It co-occurs with Sicyopterus cynocephalus (Valenciennes, 1837) , Sicyopterus stiphodonoides Keith, Allen & Lord, 2012 , Sicyopterus lagocephalus (Pallas, 1770) and Sicyopterus longifilis de Beaufort, 1912 . Etymology Sicyopterus elomionearum is a name given to honour the first author’s two daughters, Eloïse and Hermione. Indeed the first author would like to thank them for letting her leave on inventory missions for lengthy periods and also wishes to salute their great interest in their mother’s work. Because we considered that “Elomione”, born from the contraction of Elo ïse and Her mione , represents two persons, we used the plural form elomionearum for the species name.