Ancinus jarocho Ramírez, López & Rodríguez, 2010, n. sp.
Creators: name: Ramírez, Arturo Rocha -
name: López, Rafael Chávez -
name: Rodríguez, Edgar Peláez -
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Ancinidae
Ancinus
Ancinus jarocho

description: Ancinus jarocho n. sp.
(Figs 1–3)
Material examined. Holotype, male, total length 5.4 mm, Mexico, Veracruz State, National Crustacean Collection Instituto de Biología-UNAM CNCR 25957, Playa Palma Sola (19°14'45" N, 96°11'30" W), Municipio de Alto Lucero de Gutiérrez Barrios 19 February 2009, coll. Ania Peñaloza and José L. Viveros.
Paratypes, one female CNCR 25153, 5.7 mm, Playa Penacho del Indio (19°10'50" N, 96°03'39" W), Municipio de Boca del Río, 12 June 2007, one female CNCR 25156, 3.7 mm, Playa Palma Sola 11 December 2008; one female CNCR 25958, 4.8 mm, 21 January 2009; one female CNCR 25963, 5.4 mm, 19 February 2009, same locality; one female CNCR 25964, 4.7 mm, Playa Chachalacas (19°27'38" N, 96°15'04" W), Municipio de Ursulo Galván, 21, January 2009; same collectors as holotype.
Holotype and paratypes were collected in the mesolittoral zone on sandy beaches with fine sand and a density of 0.07–0.1 kg /cm2.
Diagnosis. Male body nearly 2.4 times longer than wide; ridges absent on lateral margins of pereonites and epimera; antennular flagellum of 11–16 articles, flagellar articles 7–16 with a single aesthetasc; pleotelson apex broadly rounded, apex slightly excavate; uropodal endopod robust, styliform, lightly arched, and reaching just the third quarter of the pleotelson length in females, but slightly longer in males, shortest than pleotelson; male pleopod 5 exopod with the distomesial margin serrated with minutes spines. Antennule, antenna, maxilliped, all pereopods and, pleopods 1and 2 with chromatophores dark brown, some translucid granules placed at distal margins.
Description of male. Body surface granulose. Rostrum anteriorly rounded, about 2.3 times the length of cephalon. Frontal margin of body (cephalon and pereonite 1) broadly rounded, with short medial fusion. Eyes round, elevated on swellings, small, 8.2 times the interocular space, interocular space 1.9 times cephalon width. Pereonite 1 slightly wider than the others; coxae not visible in dorsal view.
Antennule peduncle article 1 posterodistal lobe corresponds with notch in anterior margin of cephalon. Peduncular articles with short brush setae, eight, 3, and 6 respectively, articles 1 and 3 about same length, article 3 slender, 1.5 times longer than article 2; inner internal surface of peduncular article 3 and flagellar articles 2–6 with long simple setae and single distal seta; flagellum of 16 articles in holotype, 11–13 in paratypes, one aesthetasc present on flagellar articles 7–16.
Antenna extending to pereonite 3, antennal peduncular articles pigmented, increasing in length distally, article 5 1.1 and 1.4 times the length of articles 3 and 4, respectively; article 2 with 3 short dorsal setae and 3 distal brush seta, article 3 with 6 and 2 distal simple setae, articles 4 and 5 bearing numerous short brush setae and long simple setae along the ventral margin; flagellum of eight articles, articles 1–5 with numerous dorsal short brush setae, diminishing in size distally, abundant long setae in ventral margins of articles 1–3.
Maxilliped pigmented, maxillipedal palp articles 2–4 with inner distal margin lobed; articles 2–5 subequal in length, article 2 inner margin bearing 7 elongate setae and 2 short setae distally placed, article 3 bearing 5 elongate setae and 2 short setae distally placed, article 4 bearing 6 elongate setae, 2 short setae distally placed and, 4 elongate setae in outer anterior margin, article 5 bearing eight elongate setae and 2 short setae distally placed, terminal article slender; endite reaching midway on palp article 2, distally ovate with serrate margin (with minute spines), single retinaculum on medial margin and 6 elongate simple setae on proximal margin.
Mandible article 2 1.7 times as long as article 3, bearing 10 spines, article 3 curved, bearing 10 spines in distal half; left mandibular incisor strong with 3 sclerotized and 2 non-sclerotized cusps; with 2 distal cusps; spine row represented by single stout serrate spine. Right mandibular incisor with 2 sclerotized cusp, one bifurcate; lacinia mobilis with 2 sclerotized cusps; spine row with 2 serrate spines.
Maxilla 1 exopodite with eight teeth, some serrate others smooth; endopodite reduced, apex rounded.
Maxilla 2 bilobed, each lobe with a dorso-ventral hairy area, external lobe with eight minutely serrate setae, 7 apically and one subapically placed; internal lobe having 7 distal minutely serrate setae.
Pereopod 1 dactylus unguis short, less than a fifth of the length of dactylus, with elongate seta in the dorsal surface, dentiform process (scales rounded) on inner proximal half of dactylus; propodus less robust than female, about 1.7 times longer than wide, 2.4 times as long as carpus, proximally inflated; palm bearing series of densely-packed long distally-widened setae; proximal propodus process straight, robust, bearing one single seta inner distally placed, merus about 0.6 times length of propodus; basis and ischium pigmented.
Pereopod 2 longer than pereopod 1; unpigmented, dactylus elongate, curved, tipped with a small curved unguis, 7 short setae and 2 long setae, tip reaching base of propodus, basal part subequal in width to narrowest part of propodus, 1.2 times length of propodus; propodus strongly curved, palm strongly concave, inner margin of propodus bearing 4 short spines at proximal corner and one long spine distal; carpus with 7 short setae at inner medial margin and one short at outer distal margin; carpus of the same length as merus, carpus with 4 long setae at inner distal margin and 3 short spine at outer distal angle; ischium 0.7 times length of propodus, 3 different size setae at inner distal margin and 2 short setae at outer distal angle.
Pereopods 3–7 pigmented, similarly setose, tipped with curve unguis. Pereopods 3–5 about same length, smaller length than pereopods 6 and 7, dactylus about 0.5–0.6 times length of propodus; pereopods 5–7 dactylus about 0.8 times length of propodus. Pereopod 7 longest.
Pleopod 1 bearing 20 long highly plumose setae along margins. Pleopod 2 exopod slightly shorter than protopodite 2.3 times length of endopod, lateral margin having 24 long simple setae; endopod triangular, long, width of distal part of the one third 3.2 times length of endopod; 2 third outer margin having 5 plumose setae; distal third finishes in point; appendix masculina elongate-slender, just falling short of apex of endopod. Pleopod 3 destroyed in the dissection. Pleopod 4 endopod slightly longer than exopod tipped with digitiform process, with 7 small tubercles. Pleopod 5 exopod 1.1 times as long as endopod, exopod having 3 squamiferous protuberances: 2 at inner margin, one distally placed. Inner distal margin endopod finely serrated.
Uropod with protopod 1.2 times as long as endopod maximum width, styliform, lightly arched 7.5 times longer than maximum width, not reaching the pleotelsonal apex.
Sizes. Male, 5.4 mm total length. Females, 3.7–5.7 mm total length.
Colour. Life colour not recorded; pale tan in alcohol.
Etymology. The species name refers to the people born in the Veracruz State, Mexico, where the present species was collected.
Remarks. Ancinus jarocho n. sp. shares a number of features with A. granulatus: the densely granulated body surface, eyes elevated on swellings, and inflated and posteriorly truncate pleotelson. A. jarocho is easily separated from the other species by the uropodal ramus being distinctly shorter than the pleotelson. Moreover, it differs in several features: interocular space about 1.9 times cephalon width in A. jarocho and A. brasiliensis (A. belizensis has shorter interocular space, about 3.8 times and A. depressus has a longer space, about 1.8 times cephalon width).
In A. jarocho n. sp. the antennular flagellum has 11–16 articles, the antennal flagellum 8–9, (A. panamensis: 13 and 9, A. belizensis: 12 and 10, A. brasiliensis: 14 and 16 articles, A granulatus 10 and 10 and A gaucho: 11 and 10 articles, respectively). The number and disposition of aesthetascs in flagellar articles also is different, in A. jarocho n. sp. bear one aesthetasc in articles 7–16, in A. panamensis are in articles 5–12, in A. belizensis are in articles 7–12, and in A. gaucho are in articles 4–14. The antenna in A. panamensis and A. granulatus has few setae present on peduncular article 5 and flagellar articles 1–3.
In A. depressus these setae are much more numerous and present on a greatest number of articles (up to 9 articles); in A. jarocho the setae are few on peduncular articles 4–5 and flagellar articles 2–4 are with abundant long setae.
The proximal digitiform process of pereopod 1 in the male is short and robust, like to A. belizensis; relatively elongate in A. belizensis and much more robust in A. gaucho. The two distal articles of the mandibular palp bear 10 setae each one, while in A. belizensis eight and 5, 9 and 10 in A. panamensis and, 14 and 7 in A. gaucho. The pleotelson in A. jarocho, A. panamensis, A. depressus, and A. granulatus is inflated and tends to be posteriorly truncate.
Other differences among the species can be found in the key to the species of Ancinus given by Pires (1987), who modified Glynn & Glynns’ (1974) original key. We readapt the Pires´s key to include Ancinus jarocho n. sp.
description: Published as part of Ramírez, Arturo Rocha -, López, Rafael Chávez - & Rodríguez, Edgar Peláez -, 2010, Ancinus jarocho (Isopoda: Sphaeromatidea: Ancinidae), a new species from the central Gulf of Mexico, Mexico, pp. 61-68 in Zootaxa 2397 on pages 62-67, DOI: 10.5281/zenodo.194013