Phalloceros mikrommatos, Lucinda, 2008

Lucinda, Paulo Henrique Franco, 2008, Systematics and biogeography of the genus Phalloceros Eigenmann, 1907 (Cyprinodontiformes: Poeciliidae: Poeciliinae), with the description of twenty-one new species, Neotropical Ichthyology 6 (2), pp. 113-158 : 116-117

Phalloceros mikrommatos , new species

Figs. 2 , 3

Phalloceros sp. n. C Lucinda & Reis (2005).

Holotype. UFPB 5370 , unnamed stream , rio João de Tiba drainage, Estação Ecológica Pau Brasil , 15 km NW from Porto Seguro, approximately 16 o 26’S 39 o 04’W, Porto Seguro, Bahia, Brazil, 25 Feb 1986, M.M. Oliveira & R.T.C. Ramos .

Paratypes. BRAZIL. Bahia. UFPB 1751, 14, Porto Seguro, unnamed stream affluent to rio Camurigi, rio João de Tiba drainage, Estação Ecológica Pau Brasil, 15 km NW from Porto Seguro, 2 Mar 1986, R.T.C. Ramos. UFPB 1759, 7, same locality and collector of UFPB 1751, 19 Feb 1986. UFPB 2214/1*, 14 of 37, locality and collector of UFPB 1751, 27 Feb 1986. UFPB 2688, 4, riacho Ronca Água, rio João de Tiba drainage, Estação Ecológica Pau Brasil, 15 km NW from Porto Seguro, 17 Feb 1986, I. Lucena et al. UFPB 2710, 1, same locality and collector of UFPB 2688, 21 Feb 1986. UFPB 2718, 8, same locality of UFPB 2688, 22 Feb 1986, R.T.C. Ramos. UFPB 2724, 10, same locality and collector of UFPB 2718, 23 Feb 1986. UFPB 2748, 21/2*, collected with the holotype. UFPB 2758, 7, same locality and collector of UFPB 2718, 26 Feb 1986. UFPB 2776, 5, same locality of UFPB 2748, 27 Feb 1986, R. T. C. Ramos .

Diagnosis. Phalloceros mikrommatos can be distinguished from its congeners by (1) the first gonapophysis angled 5-15 degrees relative to vertebral column [53-2]; and (2) second gonapophysis angled zero-15 degrees relative to vertebral column [54-3]. Phalloceros mikrommatos can be further distinguished from its congeners but P. leticiae and P. ocellatus by the roundish to round and well-defined ocellated lateral spot [134-1] ( Fig. 2 ). Phalloceros mikrommatos can be distinguished from P. leticiae and P. ocellatus by the number of anal-fin rays in females (11 vs. 10, respectively).

Description. Morphometric data in Tables 1 and 2 . Range of SL: 18.1 to 27.0 mm (females), 17.4 to 20.4 mm (males). Dorsal-fin rays: 8* [38], 9 [6]. Branched pectoral-fin rays: 6* [16], 7 [1]. Pelvic-fin rays: 5* [11] (males), 5 [28] (females).Anal-fin rays of females: 11 [28]. Anal-fin rays of males: 9* [14]. Branched caudal-fin rays: 9 [2], 10* [16], 11 [10], 12 [1]. Predorsal scales: 14* [7]. Longitudinal series of scales: 28* [9]. Series of scales around caudal peduncle: 16* [11]. Transverse series of scales: 7* [12]. Serrae on R4p: 9 [1], 10 [6], 11* [3], 12 [3], 13 [1]. Epipleural ribs: 11 [1], 13 [1]. Pleural ribs: 13 [1], 14 [1]. Vertebrae: 31 [1], 32 [2]. Female urogenital papilla straight along midline, located along midventral line and between anus and base of first anal-fin ray. Hooks of gonopodial appendix absent ( Fig. 3 ).

Color in alcohol. Eye dark iridescent grey with greenish brown pupil. Ground pale yellow. Upper two thirds of body and head densely covered with brown chromatophores. In some individuals these chromatophores more concentrated on longitudinal line region forming faint brown discontinuous band along flanks. Lower third of flanks pale yellow contrasting with upper, darker region. Border of scales and subjacent skin replete with brown chromatophores. Chromatophores more concentrated at short distance from scale border conferring reticulate pattern to body sides, mainly on upper half. Brown chromatophores scattered through whole body, more concentrated on dorsal portion, mainly on head, snout, opercle, and ventral surface of mandible. Ocellated lateral spot rounded or roundish encircled by light ring. Vertical bars along flanks inconspicuous or absent. Dorsal-fin membrane bearing faint band of brown chromatophores on distal border of dorsal fin. Faint band of chromatophores near dorsal-fin base. Pectoral-, pelvic-, and caudal-fin rays unpigmented. Dark brown line along R3. Anal fin of females hyaline; few chromatophores scattered through first three rays but not forming defined patch of pigmentation.

Etymology.FromtheGreekµικροµµατος, −ον [= mikrommatos, -on], (adj. m. nom. sg.) meaning small-eyed, alluding to the lateral spot, which is rounded and has an external light ring. An adjective.

Distribution. Phalloceros mikrommatos is known from the rio João de Tiba drainage, a coastal drainage in the Bahia State ( Fig. 4 ).

Figures

Fig. 2. Phalloceros mikrommatos. (A) Holotype, male, 20.4 mm SL, UFPB 5370, Porto Seguro, rio João de Tiba drainage, Estação Ecológica Pau Brasil; (B) paratype, female, UFPB 2748, 21.9 mm SL, collected with the holotype.

Fig. 3. Gonopodium tip of Phalloceros mikrommatos, UFPB 2214. R3, R4a, R4p, R5a, R5p indicate gonopodial rays. Scale bar 1 mm.

Fig. 4. Collection localities of Phalloceros mikrommatos (triangle, 1), P. enneaktinos (circle, 2), P. pellos (square, 3), P. malabarbai (five-pointed star, 4), and P. heptaktinos (eightpointed star, 5). Some symbols represent more than one lot or locality. Numbers represent type localities. The inset is the range of the genus.

Tables

Table 1. Descriptive morphometrics of female specimens of Phalloceros leptokeras, P. leticiae, P. megapolos, and P. mikrommatos. Measurements 1-10 are percents of standard length and measurements 11-13 are percents of head length.

	Phalloceros leptokeras		Phalloceros leticiae		Phalloceros megapolos		Phalloceros mikrommatos
Character	n = 20		n = 3		n = 11		n = 15
	Range	Mean	Range	Mean	Range	Mean	Range	Mean
Standard length (mm)	21.7-36.5	30.1	18.4-21.4	19.8	21.7-39.7	27.4	18.1-27.0	22.1
1-Head length	17.4-21.9	19.5	23.0-26.5	24.4	19.1-24.6	21.8	20.3-24.1	22.3
2-Snout-occipital distance	18.9-23.4	20.7	19.7-22.1	20.6	14.5-20.9	18.4	16.4-21.9	19.0
3-Predorsal distance	58.6-63.8	61.3	61.9-64.1	62.8	59.7-64.7	62.4	59.7-64.0	61.7
4-Dorsal-fin base length	5.8-11.7	9.7	7.7-10.0	8.9	9.1-11.9	10.8	7.8-11.5	9.8
5-Anal-fin base length	7.5-12.3	9.7	8.4-8.8	8.6	8.5-11.7	9.8	7.7-11.5	8.9
6-Body depth	23.3-27.1	25.6	21.9-25.4	23.8	24.0-28.3	25.8	20.8-28.8	24.1
7-Pre-pelvic length	37.4-46.0	42.7	44.5-46.1	45.2	41.9-46.6	43.9	42.2-46.4	44.4
8-Preanal length	56.5-60.1	58.5	57.9-58.0	57.9	54.8-58.8	56.9	56.9-62.9	59.0
9-Postanal length	33.4-38.7	36.3	36.4-37.0	36.6	35.0-39.7	37.1	34.3-38.9	36.4
10-Caudal peduncle depth	12.7-15.7	14.5	15.6-16.0	15.8	14.1-16.9	15.6	14.6-17.9	15.9
11-Snout length	16.6-30.9	21.9	22.4-24.2	23.3	22.7-28.9	26.2	19.9-29.2	24.1
12-Orbital diameter	34.6-43.9	40.5	39.1-41.8	40.2	34.5-43.3	38.8	36.3-45.9	41.8
13-Postorbital length	36.8-52.1	44.7	39.2-42.2	40.2	35.3-44.0	38.7	31.0-43.9	38.1