Malacoctenus brunoi, Guimarães, Ricardo Z. P., Nunan, Gustavo W. & Gasparini, João Luiz, 2010

Guimarães, Ricardo Z. P., Nunan, Gustavo W. & Gasparini, João Luiz, 2010, Malacoctenus brunoi sp. n. (Blennioidei: Labrisomidae), a new scaled-blenny from Trindade Island, off Brazil, Zootaxa 2567, pp. 50-56 : 51-55

Malacoctenus brunoi n. sp.

Trindade scaled-blenny

( Figures.1–4 , Tables 1–3)

Malacoctenus sp. Nunan 1992: 248; Gasparini & Floeter 2001: 1646 and 1651. Malacoctenus oceanicus Guimarães et al. 2001: 21 (nomen nudum). Malacoctenus sp. n. Gasparini 2004: 74.

Type series: Holotype: MNRJ 21978 (ex. LBRP 5377) (36.5 mm SL), 30 March 1999 collected by J. L. Gasparini from a tide pool at Enseada dos Portugueses, Trindade Island. Paratypes (all from the same locality): LBRP 5214 (1) and LBRP 5377 (1) (collected by R. Z. P. Guimarães & C. A. Rangel, 10 October 1998), LBRP 5382 (10) (collected with holotype), CIUFES 1317 (3) (collected by J. L. Gasparini, 18 April 1998); CIUFES 1316 (3, all cleared and stained) MBML 594 (3), ZUEC 2652 (1), (collected by J. L. Gasparini & S. R. Floeter, 17 August, 1995).

Non-type material: MNRJ 12015 (5, 1 cleared & stained), MNRJ 12016 (8), CIUFES 1182 (4), CIUFES 1260 (1), CIUFES 1183 (16), CIUFES 877 (1), CIUFES 131375 (2), CIUFES 131426 (2).

Comparative material: Malacoctenus triangulatus : MZUSP 52615 (1), UFRJ 5069 (2); Recife do Pirambú, Tamandaré. Bahia: MNRJ uncat (12, 2 cleared and stained), Nova Viçosa; MZUSP 52618 (8), Abrolhos. Espírito Santo: MZUSP 52616 (8), Arquipélago das Três Ilhas, Guarapari. Rio de Janeiro: UFRJ 5039 (3), UFRJ 5084 (1), Arraial do Cabo. UFRJ 5051 (7, 2 cleared and stained), CIUFES 1318 (3), Armação dos Búzios. Malacoctenus delalandei : (22 specimens, all from the state of Rio de Janeiro, 17–55 mm SL)– LBRP 3133 (5), 3152 (1), 3145 (5, 1 cleared and stained), 3240 (2), 3057 (1), 3279 (1), 3438 (1), 3506 (2), 3153 (4).

Lateral-line scales

47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69

M. triangulatus 3 6 5 6 4 3

M. delalandei 1 1 1 1 7 3 4

M. brunoi sp. n. 2 4 6 6 4 6 6 2 Unseg. Dorsal-fin rays Seg. Dorsal-fin rays Anal-fin rays 19 20 21 9 10 11 12 13 18 19 20 21 22

M. triangulatus 39 33 7 1 1 28 8 M. delalandei 4 28 1 15 2 3 19

M. brunoi sp. n. 45 4 4 40 5 4 39 2 Diagnosis: Malacoctenus brunoi can be distinguished from its southwestern Atlantic congeners by the following combination of characters: body elongated (depth 19–22 % SL versus 23–25 % SL in M. triangulatus and 24–28 % SL in M. delalandei ), lateral line scales typically 62 – 66 (versus 50–53 in M. triangulatus and 51–53 in M. delalandei ), and the presence of two longitudinal rows of dark brown spots aligned on sides of body (versus presence of dark, reverse-triangle shaped bars in M. triangulatus and presence somewhat irregular dark bars in M. delalandei )..

Description: Non-segmented dorsal-fin rays 20; segmented dorsal-fin rays 11–13 (12); anal-fin spines two; segmented anal-fin rays 20–22 (21); segmented caudal-fin rays 13; total pectoral-fin rays 28–29 (28); pelvic fins I+3; lateral line scales 61–66 (63); space between first dorsal-fin spine and nuchal cirri bases scaleless; prepectoral area with one or two rows of scales extending to level of first two lowermost pectoralfin rays; total nasal cirri 4–5 (4); total supraorbital cirri 6; total nuchal cirri 14–17 (15); branchiostegal rays 6; vertebrae 38 (11 + 27). Body elongated, depth of body 19 to 22 % SL in specimens larger than 25 mm SL, head length 28 to 31 % SL; space between nuchal cirri bases averaging 31 to 46 % of length of a single base; snout length 7 to 9 % SL; bony orbital diameter 7 to 9 % SL; length of first dorsal-fin spine 8 to 10 % SL.

Color pattern: Body light brown, with two longitudinal rows of dark-brown spots; one almost solid, with spots strongly coalesced, extending on dorsal half of body from immediately behind orbit to end of caudal-fin peduncle, the other, with spots less coalesced, extending on ventral half of body from snout tip (snout spot absent in specimens smaller than 35 mm SL) to end of caudal-fin peduncle. Area between rows pale, sometimes with very small dark spots, and very weak dark bars. Area above dorsal row of spots light brown in specimens to ca. 35 mm SL and gray in larger ones. All fins translucent, except for gray stripe extending along distal portion of anal fin and dusky caudal fin in specimens larger than ca. 35 mm SL.

Color in life: Dark spots on head reddish brown, especially on uppermost half of orbit. Dark markings at base of dorsal-fin elements also reddish-brown. Clear markings between dark spots iridescent blue, especially on lower half of head. Pelvic fins white; all other fins translucent with yellowish tinge ( Figure 2 ).

Etymology: We honor Mr. Bruno Álvares da Silva Lobo, from 1915 to 1923 director of Museu Nacional, Rio de Janeiro, Brazil, who organized and participated in the pioneering Barroso Expedition to Trindade Island. The accounts of this expedition were reported in the Archivos do Museu Nacional ( Lobo, 1919).

Distribution: Malacoctenus brunoi sp. n. is known from the insular complex that includes Trindade Island and the Martin-Vaz Archipelago, where it is associated with shallow reefs ( Figures 6 –7).

Figures

FIGURE 1. Malacoctenus brunoi sp. n., holotype (MNRJ 21978). Photo by J. L. Gasparini.

FIGURE 2. Malacoctenus brunoi sp. n., paratype. Photographed in an aquarium immediately after collection. Photo by J. L. Gasparini.

FIGURE 3. Malacoctenus brunoi sp. n., paratype. Photographed in an aquarium immediately after collection. Photo by J. L. Gasparini.

FIGURE 4. Malacoctenus brunoi sp. n., in its natural habitat, the rocky reefs of Trindade Island. Photo by T. Simon.

FIGURE 6. Western South Atlantic, with indication of the Trindade-Vitória sea-mount chain. Arrow indicates Trindade Island, a volcanic formation laying about 1160 Km off Brazil, type locality of Malacoctenus brunoi sp. n. Map drawn by M. S. de Medeiros.