Merluccius polli Cadenat, 1950

González-Lorenzo, J. Gustavo, Triay-Portella, Raül, González-Jiménez, José F., Martín-Sosa, Pablo, Jiménez, Sebastián & González, José A., 2020, Merluccius polli and M. senegalensis (Merlucciidae) as first records from the Canary Islands (north-eastern Atlantic), with morphology data, Cybium 44 (1), pp. 57-60 : 58

Merluccius polli Cadenat, 1950

Material examined. – TFMCBM-VP/01952 , one maturing female, 624 mm TL, 559 mm SL, off Playa Nueva, Tazacorte, West of La Palma , 28°36’30”N -17°56’51”W, 476-570 m, cruise PexLa-Palma 2009, St. 32, 31 May 2009, horizontal bottom longline.

Morphology data. – Morphometrics, selected body proportions, meristics and other distinguishing features of the Canary specimen of M. polli studied are shown in Table I, and compared with data from the literature ( Cohen et al., 1990; Lloris et al., 2005, 2016). Body proportions, meristic data and other specific features of this specimen agree in all respects with published data ( Tab. I ). Its pectoral fin length almost reaches the lower limit of the species’ published range, probably reflecting different sizes of this fin: left fin nearly reaching the origin of the anal fin, but right fin reaching it ( Tab. I ; usually reaching the origin of anal fin, but not in large individuals, according to Cohen et al. (1990)). Radiographs corroborate five cervical vertebrae with three ribs on each, as attributed to this species by Cohen et al. (1990) and Lloris et al. (2005) ( Fig. 2 ; Tab. I ).

TFMCBM-VP/01952 624 mm TL present study Cohen et al. (1990) Lloris et al. (2005, 2016) Morphometrics and body proportions mm in %SL in %HL in % SL in %HL Standard length 559 – – – – Pectoral fin length (left) 97.2 17.4 – 17.7- 21.8 – Pectoral fin length (right) 94.8 17.0 – 17.7- 21.8 – Pelvic fin length 73.5 13.2 – 13.0- 16.7 – Maximum body depth 64.3 11.5 – – – Head length 145 26.0 – 24.8- 29.1 – Snout length 51.6 9.2 35.5 30.2-35.9 Upper jaw length 71.4 12.8 49.2 45.3-51.3 Eye diameter 26.2 4.7 18.0 16.4-21.8 Inter-orbital width 36.7 6.6 25.3 24.1-28.0 Pectoral fin tips reaching … Nearly reaching (left) / reaching (right) origin of anal fin Usually reaching origin of anal fin; not in large individuals Meristics First dorsal fin rays I + 10 I + 7 - 12 Second dorsal fin rays 39 36 -41 Anal fin rays 39 36 -42 Pectoral fin rays 16 (left) / 15 (right) 14 -17 Upper gill rakers (1st arch) 2 1 -3 Lower gill rakers (1st arch) 8 7 -9 Total gill rakers (1st arch) 10 8 -12 Scales along lateral line ca. 116 98 -127 Total vertebrae 56 52 -57 Cervical vertebrae 5 5 Ribs on each cervical vertebrae 3 3 Precaudal vertebrae 28 23 -28 Caudal vertebrae 28 27 -31 Other distinguishing features Soft rays All branched Scales on lacrimal Yes Dorsal surface of head Large and little depressed Caudal fin White-edged

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Remarks. – A deep-water bathydemersal species, ranging from 50 to 1098 m depth, usually shallower than 550 m, living close to the bottom on the continental shelf and slope ( Maurin, 1963; Cohen et al., 1990; Lloris et al., 2005; Manchih et al., 2018). Geographically, it is an eastern Atlantic species, distributed along the West African shelf and slope, from a locality between Cape Juby (Atlantic Morocco) and Cape Bojador ( Western Sahara) ( Maurin, 1963; Manchih et al., 2018) and southward into southwest Africa near Cape Frio, Namibia, including the Cape Verde Islands ( Reiner, 2005), ranging 29°N- 19°S, 19°W- 15°E ( Cohen et al., 1990; Maurin, 1990; Lloris et al., 2005; Manchih et al., 2018). At the northern limit of its distribution area, this nonmigratory species ( Lloris et al., 2005) is only represented by a few large individuals (500-630 mm TL) living at depths greater than 500 m ( Maurin, 1963).

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Figures

Figure 2. – Radiographs of M. polli from the Canary Islands (TFMCBM-VP/01952, maturing female, 624 mm TL). Insert: Detail of five cervical vertebrae.

Tables

Table I. – Morphometrics, body proportions, counts and other features of Merluccius polli.

		TFMCBM-VP/01952 624 mm TL present study		Cohen et al. (1990) Lloris et al. (2005	Cohen et al. (1990) Lloris et al. (2005, 2016)
Morphometrics and body proportions	mm	in %SL	in %HL	in % SL	SL	in %HL
Standard length	559	–	–	–		–
Pectoral fin length (left)	97.2	17.4	–	17.7- 21.8	21.8	–
Pectoral fin length (right)	94.8	17.0	–	17.7- 21.8	21.8	–
Pelvic fin length	73.5	13.2	–	13.0- 16.7	16.7	–
Maximum body depth	64.3	11.5	–	–		–
Head length	145	26.0	–	24.8- 29.1	29.1	–
Snout length	51.6	9.2	35.5		30.2-35.9
Upper jaw length	71.4	12.8	49.2		45.3-51.3
Eye diameter	26.2	4.7	18.0		16.4-21.8
Inter-orbital width	36.7	6.6	25.3		24.1-28.0
Pectoral fin tips reaching …	Nearly reaching (left) / reaching (right) origin of anal fin Usually reaching origin of anal fin; not in large individuals			) origin of anal fin Usually reaching origin of anal fin; not in large individuals	Usually reaching origin of anal fin; not in large individuals
Meristics
First dorsal fin rays	I + 10			I +	I + 7 - 12
Second dorsal fin rays	39			36	36 -41
Anal fin rays	39			36	36 -42
Pectoral fin rays	16 (left) / 15 (right)			14	14 -17
Upper gill rakers (1st arch)	2			1	1 -3
Lower gill rakers (1st arch)	8			7	7 -9
Total gill rakers (1st arch)	10			8	8 -12
Scales along lateral line	ca. 116			98	98 -127
Total vertebrae	56			52	52 -57
Cervical vertebrae	5				5
Ribs on each cervical vertebrae	3				3
Precaudal vertebrae	28			23	23 -28
Caudal vertebrae	28			27	27 -31
Other distinguishing features
Soft rays	All branched
Scales on lacrimal	Yes
Dorsal surface of head	Large and little depressed
Caudal fin	White-edged