Acetes maratayama Bochini, Costa & Mantelatto 2024, sp. nov.

Acetes maratayama Bochini, Costa & Mantelatto sp. nov. Figs 1, 2, 3, 4 Type material. Holotype: Brazil: • ♂ (cl 2.94 mm); CCDB 7957; São Paulo, Cananéia, Mar Pequeno; (24 ° 59 ' 55 " S, 47 ° 53 ' 49 " W); 5–10 m deep; colls. Costa, R. C. et al.; 17 April 2011. Paratypes: • 4 ♂ s and 4 ♀ s (cl 2.70 – 3.93 mm); CCDB 7958 (photo available, one dissected specimen); same data as holotype • 1 ♂ and 1 ♀ (cl 2.9 and 4.04 mm, respectively); MOUFPE 22042; same data as holotype • 1 ♂ and 1 ♀ (cl 3.04 and 3.93 mm, respectively); MZUSP 45904; same data as holotype • 2 ♂ s and 2 ♀ s (cl 4.01 – 5.19 mm); CCDB 7959; Brazil, Rio de Janeiro, Macaé; (22 ° 22 ' 13.65 " S, 41 ° 39 ' 9.42 " W); colls. Davanso, T. M. et al.; 01 September 2013 • 2 ♂ s and 2 ♀ s (cl 3.25 – 5.34 mm); MNRJ 31168; Brazil, Rio de Janeiro, Macaé; (22 ° 22 ' 13.65 " S, 41 ° 39 ' 9.42 " W); colls. Davanso, T. M. et al.; 01 September 2013 • 1 ♂ and 1 ♀ (cl 4.20 and 5.53 mm, respectively); DZ / UFRGS 7089; Brazil, Rio de Janeiro, Macaé; (22 ° 22 ' 13.65 " S, 41 ° 39 ' 9.42 " W); colls. Davanso, T. M. et al.; 01 September 2013. Additional material. •> 30 ind. (not measured); CCDB 3251; same data as holotype •> 50 ind. (not measured); CCDB 7624; Brazil, Rio de Janeiro, Macaé; (22 ° 22 ' 13.65 " S, 41 ° 39 ' 9.42 " W); colls. Davanso, T. M. et al.; 01 September 2013. Comparative material. Acetes a. americanus: • 7 ind.; CCDB 6320; Brazil, Rio Grande do Norte, Baía Formosa; (06 ° 21 ' 11.6 " S, 35 ° 00 ' 1.9 " W); colls. Lopes, M., Carvalho-Batista, A.; 25 April 2014 • 2 ♀ s (cl 3.6 and 5.1 mm); MZUSP 21210; Brazil, Alagoas, Maceió; 27 / 06 / 1989 •> 15 ind.; CCLC 258; Brazil, Espírito Santo, Anchieta, col. Braga, A. C. A.; 01 January 2014 • 10 ind.; CCDB 7626; Brazil, Rio de Janeiro, Macaé; (22 ° 22 ' 13.65 " S, 41 ° 39 ' 9.42 " W); colls. Davanso, T. M. et al.; 01 September 2013 •> 10 ind.; CCLC 253; Brazil, São Paulo, Ubatuba, col. Costa, R. C.; 02 October 2014 • 10 ind.; CCDB 4939; Brazil, São Paulo, São Vicente, col. Castilho, A. L.; 03 September 2012 • 2 ♀ s (cl 5.10 and 4.80 mm); CCLC 257; Brazil, Santa Catarina, Penha, coll. Davanso, T. M.; 24 June 2014. Acetes a. carolinae: • 2 ♂ s and 3 ♀ s; ULLZ 3274; United States, Gulf of Mexico, Louisiana; coll. Forman, W. W.; 31 October 1972. Diagnosis. Rostrum acuminate, acute; median ridge with strong posterior tooth. Carapace smooth on surface, except for post-orbital and hepatic spine. Hepatic spine present in males, external part petasma not exceeding base of capitellum; inferior antennular flagellum with 10 articles. Concavity of anterior margin of genital sternite in females forming very deep arch. Description. Male. The rostrum (Fig. 1 A, B) is acuminate, acute; the median ridge has a strong posterior tooth. There is a small supraorbital spine on each side above the eyes, near the face. The hepatic spine is present (Fig. 1 A). Quite large eyes do not exceed the posterior margin of the first antennular article (Fig. 1 A, C). Antennule with long peduncle; very elongated third article, which is approximately three times longer than the inner margin of the second article, similar to the size of the first article (Fig. 1 D); the first article in females is twice the length of the third article and approximately 4.5 × longer than the second article; the inner distal lateral margin of the first article presents simple setae in the anterior half (Fig. 1 G); males with inferior antennular flagellum have 10 articles; there is no clasping organ; males’ thickened proximal 3 - article portion occupies less than half of the flagellum; third article has 6 obtuse spinules similar to fingers, and 1 procurved and robust projection (Fig. 1 E, F); article 8 has a projection similar to a lobe in the inner lateral part of the article’s distal region (Fig. 1 E). Antennal scale extending to the middle of the second antennular peduncle article with small spine on the anterior external portion (Fig. 1 A, H). Mandible with biarticulated palp; first article of the palp 3 × longer than the second article (Fig. 2 A); first maxilla without palp (Fig. 2 B); second maxilla with one single undivided lobe (Fig. 2 C); first maxilliped without palp (Fig. 2 D); second maxilliped with 5 articles (Fig. 2 E); third maxilliped exceeding half of the antennal scale, without reaching the distal margin of the antennal scale (Fig. 2 F). The first 3 pairs of pereiopods are elongated and have a small chela (Fig. 3 A – C). Fourth and fifth pereiopods were completely absent, except for a pair of protuberances (genital thighs) in males. The sixth segment of the pleon is longer than the others (Fig. 1 A). Slender pleopods, the hind ones, are a little stockier. First pair with one single branch, with sexual appendages in males (Fig. 3 D) - the remainder has two appendages (Fig. 3 E – H). Pleopods with a row of spines on the basal articles of the endopods and exopods. PL 2 with 5 spines on the outer margin of the endopod basal joint and 5 spines on the inner margin of the exopod basal joint (Fig. 3 E); PL 3 with 12 spines on the outer margin of the endopod and with 5 ones on the outer margin of the exopod (Fig. 3 F); PL 4 with 7 spines on the external margin of the endopod (Fig. 3 G) and PL 5 with 8 spines on the external margin of the endopod (Fig. 3 H). Telson shorter than the anterior segment, long triangularly truncated at the tip (Fig. 3 I). Uropods significantly longer than the telson, external branch much longer than the internal one, with a thin tooth on the external edge closer to the tip (Fig. 3 I). The uropod exopod is 4.5 times longer than it is wide; a small spine on the outer margin in the 1 / 3 rd portion separates the ciliated portion from the non-ciliated portion (Fig. 3 I). Telson apex is truncated; lateral margins are often curved inwards and form two short teeth between which the slightly convex posterior margin is found; there are 4 bristles between the terminal teeth, the two median ones are larger than the outer teeth, and two equal-sized bristles are external to the terminal teeth (Fig. 3 J). Males. Acetes maratayama sp. nov. is very similar to the other two described Atlantic species (A. a. americanus and A. a. carolinae), except for its different petasma and female genital sternite. Petasma pars externa in A. maratayama sp. nov. does not reach the base of the capitulum (Fig. 4 B); the pars externa extends above the base of the capitulum in A. a. carolinae (Fig. 4 C). On the other hand, it extends far beyond the capitulum base and reaches the middle portion of it in A. americanus (Fig. 4 A). Pars externa insertion in A. maratayama sp. nov. is located in the middle section of the pars media (Fig. 4 B, black arrow), similar to A. a. carolinae (Fig. 4 C, black arrow). However, pars externa insertion in A. americanus is located close to the capitulum base (Fig. 4 A, black arrow). Female. The concave anterior margin of the genital sternite forms a very deep arch (Fig. 4 E, red arrow) in comparison to A. americanus (Fig. 4 D, red arrow), which has a shallow-arched concavity. The free sublateral projections by the margin’s sides are enclosed and taper to a defined point, besides being slightly curved. Acetes a. carolinae shape is similar to that of A. maratayama sp. nov.; however, the concavity of the genital sternite is not as deep, and the arch region is straight (Fig. 4 F, red arrow). The thigh of the third pair of pereopods of A. maratayama sp. nov. accounts for most of the inner margin convex and presents a small indentation (Fig. 4 E, black arrow). No tooth was found in its distal end. However, a large, oblong, acute process projects downwards the lower side of each thigh, close to the inner margin, and far forward and somewhat outward. Acetes a. americanus did not have an indentation (Fig. 4 D, black arrow) and A. a. carolinae had a small projection (Fig. 4 F, black arrow). Habitat. The species was collected by trawling in shallow waters in depths between 5 and 30 m. The bottom sediment type at the locality comprises medium and fine sand and has a salinity close to 26–28 ppt. It is considered the mesohaline area of the estuary (see Garcia et al. 2018 for environmental characterization of the Cananéia region’s bottom area). Coloration in life. Translucent like other species. Type locality. Brazil, São Paulo, Cananéia (24 ° 59 ' 55 " S, 47 ° 53 ' 49 " W). Distribution. Brazil, São Paulo, Cananéia (24 ° 59 ' 55 " S, 47 ° 53 ' 49 " W) and Rio de Janeiro, Macaé (22 ° 22 ' 13.65 " S, 41 ° 39 ' 9.42 " W). Etymology. The new species is named after the type locality, Cananéia, southern São Paulo state, Brazil. Maratayama is the old name of Cananéia recorded in the navigation log of the expedition from Portugal that arrived in the region in 1531. From the Tupi-Guarani language, Maratayama means a place where the land meets the sea or land of the sea (Mara = sea and Tayama = land). Genetic sequences. The previous genetic characterization and generated sequences obtained by Simões et al. [2023 – as “ Acetes americanus (Brazil 2) ” - https://peerj.com/articles/14751/#supplemental-information] are updated and should be referred to as Acetes maratayama sp. nov. The data, i. e., gene marker, geographic region, voucher catalogue collection and sequence accession number (GenBank), are: 16 S Ribosomal RNA (16 S) — Macaé / RJ: CCLC 0261 (OP 035684 to OP 035686), CCLC 0267 (OP 035697); Cananéia / SP: CCLC 0262 (OP 035687), CCDB 3251 (OP 035688, OP 035698 to OP 035700); cytochrome c oxidase subunit I (COI) — Macaé / RJ: CCLC 0255 (OP 060472), CCLC 0261 (OP 060504 to OP 060507), CCLC 0267 (OP 060521 to OP 060523); Cananéia / SP: CCLC 0262 (OP 060508), CCDB 3251 (OP 060509, OP 060524 to OP 060528). Some of these sequences were herein used to prepare the phylogenetic tree (Suppl. material 1). Genetic distance. 16 SrRNA gene: Intraspecific distances ranged from 0 % (A. americanus, A. maratayama sp. nov. and A. carolinae) to 0.21 % (A. paraguayensis) (Table 1). I