Euryrhynchoides holthuisi Powell, 1976

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) : 13-16

Euryrhynchoides holthuisi Powell, 1976

( Figs. 5–7 , 62 )

Euryrhynchoides holthuisi Powell, 1976: 886 , figs. 1–4.

Euryrhynchoides holthuisi — Holthuis 1993: 184, fig. 180; Pereira & García 1995: 128 (tab. 1); Pereira 1997: 3, tabs. 6, 7, 9, figs. 1, 39–41; De Grave 2007: 201; De Grave & Fransen 2011: 309.

Eurythynochoides holthuisi — Nwadiaro 1984: 134 [lap. cal.].

Eurgthynochoides holthisi — Nwadiaro 1984: 135 (tab. 1) [lap. cal.].

Material examined. Holotype: ♂ (cl 10.3 mm), RMCA 53069 , Sierra Leone, Moyamba district, Njala , Jong (Taia) River, 08°06'N 12°04'W, coll. T. van den Audenaerde, 11–12.iv.1969 . Paratypes: 4♀ (cl 10.0– 6.7 mm), RMCA 54029, same collection data as for the holotype; 2♂ (cl 9.3, 8.9 mm), RMNH 31183, same collection data as for the holotype.

Type locality. Jong (Taia) River, Njala , Moyamba district ( Sierra Leone).

Distribution. Sierra Leone (Moyamba district) and Nigeria (Rivers State) ( Powell 1976; Nwadiaro 1984) ( Fig. 62 , blue circles).

Description. Powell (1976: figs. 1–4). Additional illustrations of the type material are provided in Figs. 5–7 .

Remarks. The finding of E. holthuisi in Nigeria (Sombreiro River, Rivers State) (cf. Nwadiaro 1984) considerably extends the distributional range of this species eastward, but leaving a wide geographic gap between Sierra Leone and Nigeria ( Figs. 2 , 62 , blue circles). It is also worth noting that the Nigerian record of E. holthuisi actually falls into the known distributional range of Euryrhynchina edingtonae ( Fig. 62B ), thus raising questions as to whether this species has been misidentified with E. edingtonae . In addition, several ecological studies have been reporting E. edingtonae from Nigeria, but not E. holthuisi ( Victor & Ogbeibu 1985; Ogbeibu & Oribhabor 2002; Ikomi et al. 2005; Olomukoro 2009; Olomukoro & Dirisu 2014). Taking into account that the secimens of E. holthuisi from Sombreiro River ( Nigeria) were caught in a rocky river (a habitat similar to that of the type locality of E. holthuisi in Sierra Leone) and the fact that part of the specimens assigned to E. holthuisi by Nwadiaro (1984) were indentified by C.B. Powell (describer of the species), we tentatively accept the record of E. holthuisi from Nigeria.

Figures

FIGURE 2. Distribution map of the family Euryrhynchidae Holthuis, 1950, illustrating the known geographic distribution of the genera Euryrhynchina Powell, 1976 (yellow circles) and Euryrhynchoides Powell, 1976 (blue circles) in West Africa, and Euryrhynchus Miers, 1878 (green circles) in South America.

FIGURE 5. A–F, Euryrhynchoides holthuisi Powell, 1976: male holotype (cl 10.3 mm), Jong (Taia) River, Sierra Leone (RMCA 53069). (A) Left antennule, main and accessory rami, lateral view; (B) Fourth sternite of pereon, median region, ventral view; (C) Fifth sternite of pereon, median region, ventral view; (D) Left second pleopod, exopod and gonopod (endopod), dorsal (frontal) view; (E) Same, gonopod (endopod), mesial view; (F) Left uropod, lateral process of protopodite, dorsal view.Arrows in D and E indicate the accessory branch.

FIGURE 6. A–D, Euryrhynchoides holthuisi Powell, 1976: loose chelipeds from female paratypes (cl 10.0–6.7 mm), Jong (Taia) River, Sierra Leone (RMCA 54029). (A) Right second pereopod, lateral view; (B) Same, chela and carpus, dorsal (mesial) view; (C) Same, carpus and distal region of merus, mesial view, setae and granules omitted; (D) Right second pereopod, chela, dorsal (mesial) view, setae and granules omitted.

FIGURE 7. A–F, Euryrhynchoides holthuisi Powell, 1976: male holotype (cl 10.3 mm), Jong (Taia) River, Sierra Leone (RMCA 53069).(A) Left third pereiopod, lateral view; (B) Same, datylus and distal region of propodus, lateral view; (C) Left fourth pereopod, lateral view; (D) Same, datylus and distal region of propodus, lateral view; (E) Right fifth pereopod, lateral view; (F) Same, datylus and distal region of propodus, lateral view.

FIGURE 62. Distribution maps for the African euryrhynchids. (A–B) Euryrhynchoides holthuisi Powell, 1976 (blue circles). (B) Euryrhynchina edingtonae Powell, 1976 (yellow circles) and Euryrhynchina puteola De Grave, Piscart, Tuekam Kayo & Anker, 2017 (orange circle).The corresponding localities for each point on the maps are indicated on the Appendix 1A–C.