Phalloceros titthos, 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 : 133-134

Phalloceros titthos , new species

Figs. 25 , 26

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

Holotype. MZUSP 79670, creek near beach, approx. 25 o 53’S 48 o 37’W, Guaratuba, Paraná, Brazil, 23 Sep 1977, Expedition MZUSP / USNM.

Paratypes. BRAZIL. Paraná. MZUSP 43467, 26/3*, collected with the holotype.

Non-types. BRAZIL. Paraná. USNM 297945, 13/2*, rio da Praia, near Guaratuba, 18 Feb 1988, R.M.C. Castro.

Diagnosis. Phalloceros titthos can be distinguished from its congeners by the possession of very large papilla at the mandibular symphysis of large adult females ( Fig. 26 ).

Description. Morphometric data in Tables 11 and 12 . Range of SL: 21.0 to 45.2 mm (females), 15.1 to 25.8 mm (males). Dorsal-fin rays: 8* [21], 9 [2]. Branched pectoral-fin rays: 6 [4], 7* [14]. Pelvic-fin rays: 5 [3] (males), 4 [1], 5* [19] (females). Anal-fin rays of females: 11* [20]. Anal-fin rays of males: 9* [3]. Branched caudal-fin rays: 10 [1], 12* [14], 13 [1]. Predorsal scales: 13* [8], 14 [11]. Longitudinal series of scales: 27 [2], 28* [5], 29 [16]. Series of scales around caudal peduncle: 16* [23]. Transverse series of scales: 7* [23]. Serrae on R4p: 7 [1], 8 [1], 9 [3], 10 [1], 12 [1], 13 [2]. Epipleural ribs: 12 [2], 13 [1]. Pleural ribs: 13 [1], 14 [2]. Vertebrae: 30 [1], 32 [2]. Symphyseal papillae present ( Fig. 26 ). Female urogenital papilla straight, located along midventral line and between anus and base of first anal-fin ray. Gonopodial appendix hook present.

Color in alcohol. Eye black with greenish brown pupil. Background coloration dark brown, darker in upper half. Overall appearance dark. Border of scales and subjacent skin replete with brown chromatophores, more concentrated at short distance from scale border, conferring reticulate pattern to whole flanks. Brown chromatophores scattered through whole body, more concentrated on dorsal portion, mainly on head, snout, opercle, and ventral surface of mandible. Margin of scales on prepelvic region clearly defined bordered by dark chromatophores. Lateral dark brown spot located over 17 th and 18 th scale of longitudinal series (absent in one specimen studied). Lateral spot covering approximately one or two scales on horizontal direction, and two or three scales on vertical. Inconspicuous vertical bars present in some individuals. Dorsal-fin membrane dusky, bearing dark band of chromatophores on distal border and dark band of chromatophores near dorsal-fin base. Pectoral-, pelvic- and caudal-fin rays dusky replete of brown chromatophores distributed along fin rays. First three anal-fin rays of females sometimes spotted with black. Dark brown line along R3.

Etymology. From the Greek τιτθος [= titthós], n. m. nom. sg., a woman’s breast or animal’s teat. In allusion to the presence of small papillae at the mandibular symphysis of large adult females. Also alluding to the fact that this character is only present in adult females.

Remarks.The gonopodial tip of this species was not described and illustrated due to the lack of adult males available for study.

Distribution. Coastal drainages flowing to Baia de Guaratuba and Baia de Paranaguá in Paraná State of Brazil ( Fig. 12 ).

Figures

Fig. 25. Phalloceros titthos. (A) Male, 17.1 mm SL, USNM 297945, rio da Praia, near Guaratuba; (B) holotype, female, 35.9 mm SL, MZUSP 79670, creek near beach, Guaratuba, Paraná, Brazil.

Fig. 26. Upper and lower lip of Phalloceros titthos, MZUSP 43467, showing symphyseal papilla (SP). Scale bar 1 mm.

Fig. 12. Collection localities of Phalloceros ocellatus (circle, 1), P. tupinamba (triangle, 2), P. lucenorum (five-pointed star, 3), P. buckupi (eight-pointed star, 4), P. titthos (inverted triangle, 5), and P. caudimaculatus (square, 6). Some symbols represent more than one lot or locality. Numbers represent type localities. The inset is the range of the genus.

Tables

Table 12. Descriptive morphometrics of male specimens of Phalloceros ocellatus, P. pellos, P. spiloura, and P. titthos. Measurements 1-10 are percents of standard length and measurements 11-13 are percents of head length. H = holotype.

	Phalloceros ocellatus			Phalloceros pellos			Phalloceros spiloura			Phalloceros titthos
Character		n = 11			n = 6			n = 6		n = 1
	H	Range	Mean	H	Range	Mean	H	Range	Mean
Standard length (mm)	16.3	15.4-18.5	16.7	26.4	21.5-26.4	24.3	22.0	18.0-22.4	20.0	17.1
1-Head length	23.5	22.2-24.8	23.6	20.2	20.2-24.7	21.4	21.8	21.5-24.2	22.4	20.4
2-Snout-occipital distance	20.5	18.2-21.8	20.2	20.8	15.2-20.8	19.5	21.0	16.6-21.4	19.7	23.7
3-Predorsal distance	58.9	57.5-60.7	59.5	54.8	54.8-58.8	56.7	57.7	59.8-63.2	61.2	58.9
4-Dorsal-fin base length	7.7	7.7-13.1	10.9	11.5	8.4-11.5	10.7	13.1	10.4-12.4	11.1	11.5
5-Anal-fin base length	8.1	5.9-10.7	8.6	6.3	6.3-8.9	7.2	9.9	6.1-10.3	7.8	8.7
6-Body depth	30.5	30.5-34.0	31.9	31.1	31.1-34.5	32.0	35.0	29.9-35.9	33.1	33.9
7-Pre-pelvic length	31.3	29.4-36.8	31.4	27.9	27.9-32.1	29.3	31.4	30.7-34.7	32.1	28.4
8-Preanal length	42.4	39.5-45.7	42.2	36.0	36.0-43.6	38.8	41.5	39.6-44.3	41.4	38.3
9-Postanal length	54.3	50.3-58.6	53.9	61.7	53.9-61.7	58.9	55.4	53.2-57.4	55.2	56.9
10-Caudal peduncle depth	17.2	14.6-18.1	16.4	15.3	14.3-16.6	15.5	17.0	14.5-17.4	16.5	16.1
11-Snout length	28.3	20.4-30.7	25.9	25.6	22.6-26.2	25.1	24.8	22.0-25.9	24.1	19.5
12-Orbital diameter	41.9	39.6-48.1	44.1	38.3	36.5-48.8	40.0	45.5	38.3-46.3	42.1	45.3
13-Postorbital length	34.3	29.3-38.2	34.3	42.2	30.2-44.0	40.1	40.1	33.6-42.4	38.5	40.4