Potamalpheops tyrymembe Soledade, Santos & Almeida, 2014, sp. n.
Creators: name: Soledade, Guidomar O.
name: Santos, Patricia S.
name: Almeida, Alexandre O.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Alpheidae
Potamalpheops
Potamalpheops tyrymembe

description: Potamalpheops tyrymembe sp. n.
(Figs. 1, 2, 3 C–F)
Type material. Brazil, Bahia. Holotype: 1 m (CL 2.5 mm), mangrove between Baiano and Serra rivers near Povoado de Tremembé (14º08’51.9”S, 39º05’04.4”W), coll. A. O. Almeida, G. O. Soledade & P.S. Santos, 14.i.2013, in burrows in mud, salinity 21 (MZUSP 29585). Paratypes: 1 f (CL 3.8 mm), same collection data as for holotype (MZUSP 29586); 1 f (CL 4.1 mm), same collection data as for holotype (CCDB 4709); 1 m (CL 3 mm), same locality as for holotype, coll. A. O. Almeida, G. O. Soledade, P.S. Santos & F.L.M. Mantelatto, 10.iii.2013, burrows in mud, salinity 24 (CCDB 4710); 1 m (CL 3.5 mm), 2 f (CL 4.4, 4.0 mm), same collection data as for holotype (UESC 1536); 3 m (CL 2.8–3.2 mm), 3 f (CL 3.4–4.2 mm), same locality as for holotype, colls. A. O. Almeida, G. O. Soledade, P.S. Santos & F.L.M. Mantelatto, 10.iii.2013, burrows in mud, salinity 24 [3 specimens collected from burrows of Ucides cordatus (Linnaeus, 1763)] (UESC 1537).
Description. Carapace smooth, glabrous, without lateral grooves (Fig. 1 B). Rostrum narrow, slightly broadened at base, usually reaching half-length of cornea, never exceeding distal margin of cornea (Fig. 1 A), distally acute, without setae. Extra-corneal teeth well developed, acute; infra-corneal region broadly rounded, projecting anteriorly (Fig. 1 B, C). Pterygostomial angle slightly projecting anteriorly, rounded, without setae (Fig. 1 B). Cardiac notch well developed.
Abdominal somites 1–5 with posteroventral angles rounded; sixth somite with triangular articulated flap posteroventrally (Fig. 1 I); posterior margin subrectangular with minute subacute tooth (Fig. 1 I). Telson relatively broad, subrectangular, slightly tapering distally (Fig. 1 H), with two pairs of dorsal spiniform setae (Fig. 1 H); posterior margin medially rounded, with two pairs of stout spiniform setae near each lateral angle, mesial slightly shorter than lateral (Fig. 1 H); anal tubercles absent.
Eyes largely exposed in dorsal and lateral views (Fig. 1 A–C); cornea well pigmented, occupying most of eyestalk except for mesial and anteromesial portions; anteromesial margin with about five setae (Fig. 1 D). Ocellar beak not visible in dorsal view.
Antennular peduncle slender, second segment slightly longer than visible portion of first segment in dorsal view (Fig. 1 A); first segment with distal margin smooth, dorsal margin with small spiniform setae (Fig. 1 A); stylocerite acute, overreaching distal margin of first segment (Fig. 1 A); ventromesial carina with well-developed tooth, as illustrated (Fig. 1 F); lateral flagellum biramous, with 7–15 tufts of aesthetascs, accessory branch with 2–3 segments (Fig. 1 E). Antenna with basicerite bearing acute ventrolateral tooth (Fig. 1 B, C); scaphocerite not reaching distal margin of antennular peduncle, distolateral tooth robust (Fig. 1 A), anterior margin convex, not exceeding distolateral tooth (Fig. 1 A); carpocerite short, with distal margin reaching to about 0.7 of scaphocerite (Fig. 1 B); flagellum not particularly thickened, slender.
Mandible with incisor process bearing six triangular acute teeth, two central being largest (Fig. 1 G); molar process with circular rows of short, stiff setae; endopod (palp) bi-articulated, distal segment broader than proximal segment. Maxillule with endopod (palp) bilobed; distal lobe distinctly larger than ventral, with distal seta, proximal lobe with stout distal seta. Maxilla with scaphognathite rather narrow; dorsal endite without incision; endopod (palp) slender, non-setose. First maxilliped with well-developed caridean lobe on exopod; endopod (palp) with long distal plumose setae; epipod subrectangular. Second maxilliped typical for Alpheidae, without specific features, epipod elongate. Third maxilliped slender (Fig. 2 A); tip of ultimate segment with 2–3 small spiniform setae; exopod well developed; coxal lateral plate ear-shaped, distally subacute, covering base of exopod.
First pereiopods = chelipeds (Fig. 2 B–E) symmetrical, not significantly enlarged compared to second pereiopod; ischium elongate; merus slightly longer than ischium and carpus (Fig. 2 B, C); carpus cylindrical, slightly widened distally, ventromesially with at least five rows of grooming setae (Fig. 2 D); chela subcylindrical, longer than carpus, fingers shorter than palm (Fig. 2 D, E), with scattered tufts of setae, cutting edges unarmed. Second pereiopod slender (Fig. 2 F); ischium and merus subequal in length, slender; carpus five-segmented; ratio of carpal segments approximately equal to (proximal to distal): 3.3: 1: 1.2: 1.1: 2.4 (Fig. 2 F); chela simple, as long as distal carpal segment; fingers slightly shorter than palm. Third pereiopod slender (Fig. 2 G); ischium armed with one spiniform seta; merus armed with two spiniform setae (Fig. 2 G); carpus unarmed, distally with stiff seta; propodus armed with 4–7 minute spiniform setae on ventral margin, including one distal spiniform seta (Fig. 2 G); dactylus about 0.4 length of propodus, conical, simple, slender, gradually and slightly curving distally (Fig. 2 G). Fourth pereiopod (Fig. 2 H) similar to third pereiopod. Fifth pereiopod (Fig. 2 I) similar to third and fourth pereiopods; ischium unarmed; merus armed with two spiniform setae; propodus with three minute spiniform setae on ventral margin, about seven rows of grooming setae, and tufts of long distal setae (Fig. 2 I).
Second pleopod with appendix masculina twice as long as appendix interna, with four long distal setae (Fig.
2J). Uropodal exopod conspicuously longer than endopod (Fig. 1 H), with diaeresis finely toothed for about 0.7 length between distolateral tooth and abrupt incision, with 15–21 minute, triangular teeth (Fig. 1 J); distolateral spiniform seta stout, not reaching posterior margin of exopod (Fig. 1 J); distolateral tooth acute, approximately 0.25 length of distolateral spiniform seta (Fig. 1 J).
Morphological variation. No conspicuous morphological differences exist between the males and the females, although the latter are significantly larger (mean CL 4.07 ± 0.36 mm for females vs. mean CL 2.95 ± 0.37 mm for males, p = 0.0042). The rostrum usually reaches to the middle of the cornea, but can reach as far as the anterior margin of the cornea. The number of aesthetasc tufts on the lateral antennular flagellum is variable (7–15), with the majority of specimens having 11 tufts. The number of segments in the accessory ramus is usually two or three. The number of spiniform setae on the P3 and P4 propodi varies from four to seven, with six being the predominant number for P3 propodus. Most specimens bear two (rarely one) spiniform setae on the P5 merus. The number of teeth on the diaeresis of the uropodal exopod is generally 15 or 16; only two specimens have more than 16 teeth.
Color pattern. Body semi-translucent, with chromatophores varying from brownish to orange (Fig. 3 C, E); chromatophores irregularly and sparsely distributed on carapace, arranged in narrow transverse bands on abdomen (Fig. 3 C–E), bands located close to posterior margin of each abdominal somite, wider dorsally; telson and uropods with bluish pigmentation intensifying towards distal end (Fig. 3 F); antennal and antennular flagella and pereiopods pale bluish; eyes reddish to pink (Fig. 3 C–E); eggs brownish (Fig. 3 C).
Type locality. Brazil, Bahia, Maraú, mangrove between Baiano and Serra rivers near Povoado de Tremembé (14º08’51.9”S, 39º05’04.4”W).
Distribution. Presently known only from the type locality in Bahia, Brazil.
Ecology. All specimens of P. tyrymembe sp. n. were collected on a mangrove flat, from burrows in mud, near the roots of the red mangrove tree, Rhizophora mangle L. (Fig. 3 A). At least some of them were found in burrows with a typical shape of those of the ucidid crab Ucides cordatus (Fig. 3 B). The shrimps were always obtained after the first pump suction, suggesting a more superficial location in the burrow. Specimens of P. tyrymembe sp. n. were also obtained from burrows shaped similarly to those of the snapping shrimp Alpheus pontederiae de Rochebrune, 1883. However, although syntopic, these two very different alpheid species have never been collected simultaneously from the same burrow. Salinities recorded at the collection site were 21 and 24.
Etymology. The specific name refers to the type locality, "Tremembé", which is derived from the word " tyrymembé " in the Tupi language (indigenous group in Brazil), meaning "swamp" or "marsh" (Tibiriça 2009).
description: Published as part of Soledade, Guidomar O., Santos, Patricia S. & Almeida, Alexandre O., 2014, Potamalpheops tyrymembe sp. n.: the first southwestern Atlantic species of the shrimp genus Potamalpheops Powell, 1979 (Caridea: Alpheidae), pp. 579-586 in Zootaxa 3760 (4) on pages 580-584, DOI: 10.5281/zenodo.226557