Centropomus irae, Carvalho-Filho & Oliveira & Soares & Araripe, 2019

Carvalho-Filho, Alfredo, Oliveira, Joiciane De, Soares, Camila & Araripe, Juliana, 2019, A new species of snook, Centropomus (Teleostei: Centropomidae), from northern South America, with notes on the geographic distribution of other species of the genus, Zootaxa 4671 (1), pp. 81-92 : 83-86

Centropomus irae sp. nov. Carvalho-Filho, Oliveira, Soares & Araripe

( Fig. 2 ; Tables 1–2 )

Holotype. MPEG 30613, 326.3 mm SL. Brazil, Amapá, Oiapoque, Baía do Oiapoque (Lat. 3.84 /Long. -51.82), A. Costa and J. Oliveira, 23 February 2014.

Paratypes. (9 specimens). MPEG 30614 , 05 , 233.4–409.1 mm SL ; MZUSP 115987 , 02 , 312.2–360.2 mm SL ; MNRJ 42279, 353.4 mm SL; and ZUEC 8465, 346.3 mm SL, all collected together with the holotype .

Non-type specimens. (13 specimens). Excluded from the type material because of damage. MPEG 30615 , 13 , 272.4 – 318.2 mm SL, same data as for holotype .

Diagnosis. The new species differs from all its congeners by the typically brown-colored lateral line, mean interorbital width (4.1% of SL vs. 5.2–6.9%), mean snout length (8.9% of SL vs. 9.8–11.1%), mean orbit diameter (4.5% of SL vs. 5.4–7.3%), and mean mandible length (15.7% of SL vs. 19.9–21.6%). It can also be differentiated from the similar Centropomus undecimalis by the number of scales around the caudal peduncle (18–22, usually 19–21, vs. 22–28, usually 24–27).

Description. Meristic and morphometric data are presented in Tables 1 and 2 . Body elongate, sub-cylindrical in cross section, deeper at first dorsal fin origin. Head large, about one third of SL (33–36%, mean 33.5%). Dorsal profile of head slightly concave from snout to nape, gently curved from nape to origin of first dorsal fin. Mouth relatively large, maxillary almost reaching posterior margin of orbit. Mandible short, mean 15.7% SL. Orbit diameter relatively small, around half of snout length, mean 4.5% SL. Interorbital width narrow, mean 4.1% SL. Snout length small, mean 8.9% SL. Preorbital faintly serrated. Opercular flap extending to 6th or 7th pored lateral line scale and about 4 dorsal scales before origin of first dorsal fin. Margin of preoperculum almost entirely serrated, with 4 to 6 enlarged spines at angle. Upper limb of preoperculum with upper serrae dorsally-oriented, other serrae straight; lower limb of preoperculum never smooth, with two short, obtuse, closely located spines near angle, and usually with pointed serrae, which may include some short obtuse spines. Distal margins of interoperculum and suboperculum smooth. Center of external preopercular shelf with 0–2 spines, one conspicuous, sharp, usually present in angle, often with one markedly shorter spine ventrally. No tooth patch on ectoperygoid. Band of laterally exposed premaxillary teeth not extending to dorsal margin of the bone, gradually tapering to point posteriorly. Gill rakers on first branchial arch 12–15 without rudiments, 8–10 on lower limb (one specimen with 10), 4 or 5 on upper limb (one specimen with 5); total gill rakers 18–22 with rudiments; gill rakers long, those at center of first arch at least twice as long as gill filaments.

Pectoral fin as long as, but usually shorter than pelvic fin, and far from reaching its tip; pelvic fin not reaching anus. Third dorsal-fin spine longer than fourth. Second anal-fin spine not extending beyond middle of caudal peduncle, its length similar to third anal-fin spine. Lateral line scales 67–74; lateral scale rows 72–80; scales on caudal peduncle 18–23, usually 19–21 (one specimen with 23); scales from origin of second dorsal fin to lateral line 9–11; scales from origin of anal fin to lateral line 10–12 (one specimen with 10). For further comparisons with other congener species, see Discussion

Color of live specimens. Upper head and dorsum brown to tan, often with bluish hue; sides silvery gray to golden with faint longitudinal lines darker due to the dark center of scale rows, more evident in the upper-posterior body and close to lateral line. Lateral line usually brown in riverine and estuarine specimens, darker in sea-caught specimens which also lack golden hue on sides, being more silvery gray in general coloration. Operculum pearl with irregular, variable, golden area, more conspicuous close to posterior border of eye. Dorsal fins-rays and/or spines sometimes suffused with dark gray; first dorsal fin spines brownish to light tan, membrane pearly gray to translucid golden; second dorsal fin spine and rays brownish to light tan, membrane translucid golden; upper lobe of caudal fin tan to yellowish, lower lobe darker, often suffused with black; anal fin tan, golden or yellowish, sometimes suffused with black; pelvic fin tan to light yellow, suffused with golden hue; pectoral fin colorless to light yellow, often suffused with golden hue.

Color of preserved specimen. brownish and golden colors disappear, resulting in a gray or silvery-gray coloration, respectively; lateral line brownish-gray. Fins pale with faint traces of yellow, portions suffused with black more evident.

Etymology. The new species is named after Dr. Iracilda Sampaio (Federal University of Pará, Bragança, Pará, Brazil) in recognition of her lifelong contribution to the understanding of the genetic diversity of the fauna of the Amazon region, in particular fish, and her profound dedication to science and teaching. Proposed English name: Ira’s Snook. Proposed Portuguese (Brazilian) name: Camorim Irá.

Distribution and habitat. Centropomus irae sp. nov. is currently known only from the specimens presented here, which were collected in Oiapoque Bay, between Brazil and French Guyana, and the Lago Piratuba Biological Reserve, both in Amapá state, Brazil, northeastern South America. In the case of the large Piratuba lagoon ( Fig. 1 ), Centropomus irae sp. nov. was observed in the more saline waters, close to the outlet channel of the lagoon to the sea, as confirmed by local fishermen, and also in the center of the lagoon. Unfortunately none of the specimens collected from the lagoon could be preserved, and were lost, but we were able to take a picture of the largest individual (535.5 mm SL, Fig. 2C ), and to take measurements and counts of two large specimens from this locality (see Table 1 ).

Figures

FIGURE 1. Collecting localities of the Centropomus irae sp. nov. specimens (black dots) in Amapá, northern Brazil.

FIGURE 2. Specimens of Centropomus irae sp. nov. A – Holotype (MPEG 30613), 326.3 mm SL. B – Paratype (MPEG 30614), 233.4 mm SL. C – Unpreserved specimen, 535.0 mm SL, from Lake Piratuba. Photographs: Alfredo Carvalho Filho.

Tables

TABLE 1. Centropomus irae sp. nov.: selected counts and measurements as a percentage of the SL.

Character	Holotype	Paratypes	Non-type	Lago Piratuba	Proportions	Range
Number of Specimens		(9)	(13)	(2)	Mode	(25)
					(25)
Standard Length (mm)	326.1	233.3–353.5	272.4–318.2	497.3–535.0	352.9	233.3–535.0
Body depth	24.5	22.1–24.3	19.0–25.2	22.4–22.6	22.6	19.0–25.2
Head length	36.2	33.6–35.7	33.3–36.3	33.2–33.3	34.8	33.3–36.3
Snout length	8.9	8.5–9.7	8.3–9.3	8.2–8.5	8.9	8.3–9.7
Orbit diameter	4.5	3.8–4.7	4.2–5.3	3.7–3.9	4.5	3.8 – 5.3
Interorbital width	4.4	3.7–4.7	3.9–4.4	3.9–4.1	4.1	3.7–4.7
Postorbital length	22.2	21.0–22.1	19.6–22.5	20.9–21.6	21.3	19.6–22.5
Maxillary length	13.9	13.3–14.8	13.2–14.3	13.0–13.1	13.7	13.2–14.8
Mandible length	16.0	15.0–16.5	15.3–16.6	14.9–15.0	15.7	15.0–16.6
First predorsal length	42.0	37.3–40.9	38.2–42.9	38.9–39.0	40.2	37.3–42.9
Second predorsal length	67.5	62.7–66.5	61.8–67.8	63.0–64.1	65.0	61.8–67.8
Prepelvic length	34.6	31.5–40.4	34.2–39.4	35.8–36.4	36.3	31.5–40.4
Pectoral-fin length	20.3	17.6–20.1	17.9–20.3	17.1–17.7	18.9	17.6–20.3
Pelvic-fin length	22.4	19.0–21.1	19.2–24.2	19.2–21.2	20.5	19.0–24.2
First dorsal base length	18.6	17.8–19.7	15.8–18.2	18.3–18.6	17.8	15.8–19.7
Second dorsal base length	16.7	16.2–17.8	13.5–16.6	16.3–16.9	16.0	13.5–17.8
Anal-fin base length	11.0	10.7–13.8	8.6–11.0	11.2–12.0	10.5	8.6–13.8
Caudal-peduncle depth	11.0	8.7–13.5	9.8–11.7	9.9–9.9	10.6	8.7–13.5
First dorsal-fin elements	VIII-I,10	VIII-I,10	VIII-I,10	VIII-I, 10		VIII-I, 10
Anal-fin elements	III,6	III,6	III,6	III,6		III,6
Pectoral-fin rays	13	13–15	14–15	15		13–15
Pelvic-fin elements	I,5	I,5	I,5	I,5		I,5
Lateral-line scales	71	67–74	67–74	68–72		67–74
Lateral scales rows	76	72–80	72–80	72–76		72–80
Scales above lateral line	10	09–11	09–11	09–10		09–11
Scales below lateral line	11	11–12	11–12	11		11–12
Scales around peduncle	21	19–22	18–22	21-23		18–23
Upper-limb gill rakers	04	04–05	04–05	05		04–05
Lower-limb gill rakers	08	08–10	08–09	08		08–10
Gill rakers with rudiments	19	17–22	18–20	17–18		17–22

TABLE 2. Range and mean (in parentheses) values for selected characters of the Atlantic Centropomus species, based on Rivas (1986) and the present study. The measurements expressed as thousands of the SL. The total number of gill rakers excluding rudiments.

Species	C. irae	C. ensiferus	C. mexicanus	C. parallelus	C. pectina-	C. poeyi	C. undecimalis
					tus
Character
SL mm	233–535	112–270	105–345	104–445	101–362	190–276	109–471 (242)
	(353)	(196)	(202)	(237)	(224)	(223)
Head length	333–363	371–421	352–386	347–403	328–374	364–382	345–389 (368)
	(348)	(395)	(370)	(377)	(351)	(372)
Snout length	83–97 (89)	98–123	94–116 (106)	103–116	100–114	93–101	89–112 (101)
		(111)		(110)	(108)	(98)
Orbit length	38–53 (45)	50–71 (57)	59–88 (73)	56–78 (67)	56–77 (66)	60–72	38–64 (54)
						(64)
Interorbital	37–47 (41)	52–63 (57)	49–66 (57)	56–70 (64)	53–66 (61)	60–72	44–61 (52)
						(64)
Mandible	150–166	186–214	198–216	188–224	188–217	208–225	201–228 (216)
length.	(157)	(199)	(210)	(210)	(199)	(214)
Anal-fin rays	III,6	III, 6	III, 6	III, 6	III,7	III, 6	III, 6
Lateral scales	72–80	49–59	68–78	79–92	61–71	73–80	67–77
rows
Total Gill	12–15	14 –22	14–17	14–17	19–23	15–18	11 –14
Rakers
Scales around	18–23	18–23	24–28	26–31	20–22	24–29	22–28
peduncle