Euryrhynchus tomasi De Grave, 2007

Pachelle, Paulo P. G. & Tavares, Marcos, 2018, The freshwater shrimp family Euryrhynchidae Holthuis, 1950 (Crustacea: Decapoda: Caridea) revisited, with a taxonomic revision of the genus Euryrhynchus Miers, 1878, Zootaxa 4380 (1) : 65-72

Euryrhynchus tomasi De Grave, 2007

( Figs. 1E , 44B , 45–49 , 65A )

Euryrhynchus tomasi De Grave, 2007: 194 , figs. 1–7.

Euryrhynchus tomasi — De Grave & Fransen 2011: 309; Pimentel & Magalhães 2014: 1302, fig. 2 [as E. burchelli Calman, 1907 , partim].

Material examined. Holotype: ♂ (cl 5.0 mm), NHM 2007.62 , French Guiana, Cayenne , Ouanary , 20 km northwest of St Georges de l’Oyapock, Crique Timothy, approximately 04°00'N 51°52'W, coll. J. Tomas, 29.iii.2006.

Paratype: 1♀ (cl 6.5 mm), NHM 2007.63 , same collection data as for the holotype. Additional material: French Guiana: 1♂ (cl 4.1 mm), 1♀ (cl 5.0 mm), OUMNH.ZC.2015-02-007, Cayenne, Kourou, 15 km south of Kourou city, Montagne des Singes , 05.0718°N 52.6928°W, coll. O. Helke, 2012. Brazil : 8♂ (cl 5.1–4.0 mm), 2♀ (cl 4.9, 4.5 mm), 9♀ ov (cl 5.2– 4.6 mm), MZUSP 22766 , Amapá, northwest of Amapá city, Vilarejo e Balneário Cachoeira Grande , in cave, 02°09'52.2''N 50°55'22.8''W, in submerged leaflitter, coll. J.M. Cunha & J. Zuanon, 06.iii.2007 ; 1♂ (cl 4.2 mm), 1♀ov (cl 5.0 mm), OUMNH.ZC.2016-01-028, same collection data as previous lot; 2♂ (cl 3.2, 2.5 mm), 6♀ (cl 4.2– 2.6 mm), INPA 1082 , Amapá, north of Amapá city, Rio Amapá Grande, Cachoeira Grande , small igarapé downstream, coll. C. Magalhães & Roberval, 26.viii.1992 .

Type locality. Crique Timothy , 20 km northwest of St Georges de l’Oyapock , Ouanary, Cayenne ( French Guiana).

Distribution. French Guiana (Cayenne) and Brazil (Amapá) ( De Grave 2007; present study) ( Fig. 65A , green circles).

Description. De Grave (2007), figs. 1–7. The Brazilian material is illustrated on Figs. 45–49 .

Remarks. Euryrhynchus tomasi resembles E. burchelli in having the second pereopod merus with a pair of spines on the distoventral angles ( Figs. 25D , 46D ), the third to fifth pleopods of female with appendix interna ( Figs. 29I –K , 48I –K ), and the gonopods elongated, straight ( Figs. 29B, C , 30 , 48B, C , 49 ). However, E. tomasi can be easily recognized by (i) the second pereopod carpus with distomesial angle unarmed, smooth, Fig. 46D (versus second pereopod carpus with 1 subdistal spine on the distomesial angle in E. burchelli , Fig. 25D ), (ii) the second pereopod provided with fine granules at least on the surface of carpus and propodus, Fig. 46 (versus second pereopod without fine granules on surface of articles in E. burchelli , Fig. 25 ), and (iii) the fourth thoracic sternite with transversal ridge produced into prominent, triangular lobe medially, Fig. 45D (versus fourth thoracic sternite with transversal ridge produced into low, broad lobe medially in E. burchelli , Fig. 24D ). According to De Grave (2007) the second to fifth pleopods lack appendix interna in the females. However, all female specimens examined during the present study, including the female paratype, do actually have appendix interna on the third to fifth pleopods ( Fig. 48I –K ).

Pimentel & Magalhães (2014) reported three lots of E. burchelli from Amapá, Brazil (INPA 1082; IEPA 0 0 27, 0050). However, the specimens of the lot INPA 1082 actually belong to E. tomasi (see remarks under E. burchelli ), thus representing the first finding of the species in the Brazilian Amazon.

Figures

FIGURE 1. Species of Euryrhynchus Miers, 1878, photographed in aquarium (unknown procedence). (A–C) males of E. amazoniensis Tiefenbacher, 1978, sensu lato; (D) ovigerous female of E. amazoniensis sensu lato; (E) male of E. tomasi De Grave, 2007; (F) male of E. wrzesniowskii Miers, 1878. Photographs kindly provided by Chris Lukhaup (A, D, E), Brian Ma (C) and Joachim Tomas (B, F).

FIGURE 24. A–J, Euryrhynchus burchelli Calman, 1907: male (cl 6.0 mm), Sítio São Bento, Roraima, Brazil (MZUSP 34207). (A) Anterior region of the arapace, dorsal view; (B) Same, eyes and frontal margin, dorsal view, setae omitted; (C) Same, lateral view; (D) Fourth sternite of pereon, median region, ventral view; (E) Fifth sternite of pereon, median region, ventral view; (F) Telson, dorsal view, setae omitted; (G) Right antennule, main and accessory rami, ventral view; (H) Right thirdmaxilliped, lateral view; (I) Right first pereopod,lateral view;(J) Right uropod,exopodand lateral process of protopodite, dorsal view, setae omitted.

FIGURE 29. A–J, Euryrhynchus burchelli Calman, 1907:(A–F) male (cl 6.0 mm), Sítio São Bento, Roraima, Brazil (MZUSP 34207); (G–K) female (cl 6.0 mm) same lot as previous specimen. (A) Right first pleopod, ventral view; (B) Right second pleopod,ventral view;(C)Same,gonopod (endopod) and exopod, dorsalview; (D)Right third pleopod,ventral view;(E)Right fourth pleopod, ventral view; (F) Right fifth pleopod, ventral view; (G) Right first pleopod, ventral view; (H) Right second pleopod, ventral view; (I) Right third pleopod, ventral view; (J) Right fourth pleopod, ventral view; (K) Right fifth pleopod, ventral view. Plumose setae omitted.

FIGURE 30. A–F, Euryrhynchus burchelli Calman, 1907: male, Igarapé Sabure, left bank of Rio Negro, São Gabriel da Cachoeira, Amazonas, Brazil (MZUSP 34201). (A) Right second pleopod, ventral view; (B) Same, dorsal view; (C) Same, mesial view; (D)Same, detail of apex, dorsalview; (E)Same, appendix interna,lateral view;(F)Same,rows of cuspidatesetae, dorsal view.

FIGURE 45. A–J, Euryrhynchus tomasi De Grave, 2007: male (cl 5.1 mm), Vilarejo e Balneário Cachoeira Grande, Amapá, Brazil (MZUSP 22766). (A) Anterior region of the body, dorsal view; (B) Same, eye and part of frontal margin of carapace, setae omitted; (C) Same, lateral view; (D) Fourth sternite of pereon, median region, ventral view; (E) Fifth sternite of pereon, median region, ventral view; (F) Telson, dorsal view, setae omitted; (G) Right antennule, main and accessory rami, ventral view; (H) Right third maxilliped, lateral view; (I) Right first pereopod, lateral view; (J) Right uropod, dorsal view, setae omitted.

FIGURE 46. A–E, Euryrhynchus tomasi De Grave, 2007: male (cl 5.1 mm), Vilarejo e Balneário Cachoeira Grande, Amapá, Brazil (MZUSP 22766). (A) Left second pereopod, lateral view; (B) Same, chela and carpus, dorsal (mesial) view; (C) Right second pereopod,lateral view; (D) Same, carpus and distal region ofmerus, mesial view,setae and granulesomitted; (E) Same, chela and carpus, dorsal (mesial) view.

FIGURE 47. A–G, Euryrhynchus tomasi De Grave, 2007: male (cl 5.1 mm), Vilarejo e Balneário Cachoeira Grande, Amapá, Brazil (MZUSP 22766). (A) Right third pereopod, lateral view; (B) Same, dactylus and distal region of propodus, lateral view; (C) Right fourth pereopod, lateral view; (D) Same, dactylus and distalregion of propodus,lateral view; (E)Same, mesial view; (F) Right fifthpereopod, lateral view; (G) Same, dactylus and distal region of propodus, lateral view.

FIGURE 48. A–K, Euryrhynchus tomasi De Grave, 2007: (A–F) male (cl 5.1 mm), Vilarejo e Balneário Cachoeira Grande, Amapá, Brazil (MZUSP 22766); (G–K) female (cl 4.9 mm), same lot as previous specimen. (A) Left first pleopod, ventral view; (B) Right second pleopod, ventral view; (C)Same,gonopod(endopod)and exopod, dorsalview;(D)Right third pleopod, ventral view; (E) Right fourth pleopod, ventral view; (F) Right fifth pleopod, ventral view; (G) Right first pleopod, ventral view; (H)Right second pleopod, ventral view; (I) Right third pleopod, ventral view; (J) Right fourth pleopod, ventral view; (K) Right fifth pleopod, ventral view.Plumose setae omitted.

FIGURE 49. A–G, Euryrhynchus tomasi De Grave, 2007: male, Vilarejo e Balneário Cachoeira Grande, Amapá, Brazil (MZUSP 22766).(A) Right second pleopod, ventral view; (B) Same, mesial view; (D) Same, dorsal view; (E) Same, detail of apex, dorsal view; (F) Same, appendix interna, ventral view; (G) Same, median rows of cuspidate setae, dorsal view.

FIGURE 65. Distribution maps for the South American euryrhynchids Euryrhynchus tomasi De Grave, 2007 (green circles) and Euryrhynchus tuyuka sp. nov. (blue circle) (A) and Euryrhynchus wrzesniowskii Miers, 1878 (B). The corresponding localities for each point on the maps are indicated on the Appendix 1H–J.

FIGURE44. A–B, Euryrhynchus taruman sp. nov., male (cl 5.9 mm) from Igarapé Tubana,tributary of Rio Jufari,Amazonas, Brazil (MZUSP 34530), lateral view (A); Euryrhynchus tomasi De Grave, 2007, male holotype (cl 5.0 mm), Crique Timothy, north-west of St Georges de l’Oyapock, French Guiana (NHM 2007.62), lateral view (B). Photographs kindly provided by Joel Braga de Mendonça Jr.(A) and Joachim Tomas (B).

FIGURE25. Euryrhynchus burchelli Calman, 1907:male (cl 6.0 mm), Sítio São Bento, Roraima, Brazil (MZUSP 34207). (A) Left second pereopod,lateral view; (B) Same, chela and carpus, dorsal (mesial) view; (C) Right second pereopod, lateral view; (D) Same, carpus and distal region of merus, mesial view, setae omitted; (E) Same, chela andcarpus, dorsal (mesial) view.