A proposal to synonymize the freshwater crab Hypolobocera olgaluciae Ramos-Tafur and Ríos , 2007 with Hypolobocera buenaventurensis ( Rathbun , 1905 ) from Colombia ( Crustacea : Decapoda : Pseudothelphusidae )

Hypolobocera olgaluciae Ramos-Tafur and Ríos, 2007 is considered herein as junior synonym of H. buenaventurensis (Rathbun, 1905) taking into account that the morphological diff erences on the fi rst male gonopod are not signifi cant and are the consequence of natural variations of the populations. Th e fi rst male gonopod of H. buenaventurensis is redescribed and illustrated.


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The morphological characters of the first male gonopod are essential for the taxonomic determination of the species of freshwater crabs (Smalley, 1964).Th is specifi city is due to the fact that the gonopod and the female opening form a lock/key system with the function of transferring the sperm to the female.
Each genus is characterized by a general pattern associated to the fi rst male gonopod: presence and shape of the lateral lobe, accessory lobe, mesial lobe, processes, and projections.All species of a genus share the general pattern, but each species is distinguished by a set of specifi c morphological characters; they determine the identity of the species and allow its diff erentiation with respect to the other species of the genus.In general, for a given species there are diff erent populations and the specifi c environmental conditions can induce small changes in the morphological characters but the identity of the species is held (Rodriguez, 1982).Some examples described in the literature serve to illustrate the previously mentioned fact: (A) In the revision of the genus Neostrengeria Pretzmann, 1965, the author describes morphological variations of the fi rst male gonopod of some species, particularly on the lateral lobe, the accessory lobe, the apex outline and the meso-caudal projection of the spermatic channel, which are due to populational variations (Campos, 1994).(B) In the case of the genus Hypolobocera Ortmann, 1897, the variations appear on the lateral lobe and the apex outline (Campos, 2003: Figs. 5A, B;17E, F). (C) Campos and Guerra (2008) synonymized the freshwater crab species Hypolobocera solimani Ramos-Tafur, 2006 with Hypolobocera alata Campos, 1989, andHypolobocera triangula Ramos-Tafur, 2006 with Hypolobocera rotundilobata Rodríguez, 1994, because the morphological diff erences represent natural variations within the populations.
Ramos-Tafur and Ríos (2007) described a new species of freshwater crab of western Colombia: Hypolobocera olgaluciae Ramos-Tafur and Ríos, 2007.After the taxonomic identifi cation of the species based on the morphology of the first male gonopod, the authors concluded that the new species was closely related to Hypolobocera buenaventurensis (Rathbun, 1905).
In the present work, after comparing the holotype of H. olgaluciae with material of H. buenaventurensis Nauplius from the Marine Biology Collection, Universidad del Valle (CRBMUV), Cali, Colombia, we concluded that the morphological differences of the first male gonopod correspond to populational variations of the species.Accordingly, here we propose H. olgaluciae as junior synonym of H. buenaventurensis.
The terminology used for the different processes of the gonopod follows Smalley (1964) and Campos (2005;2014).The material examined is deposited in the Marine Biology Collection, Universidad del Valle (CRBMUV) and in the collection of the Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia (ICN-MHN-CR).The following abbreviations are used: carapace breadth (cb), which is measured across the carapace at its widest point; carapace length (cl), measured along the midline, from the frontal to the posterior margin.
the CRBMUV collection and she found a male specimen of Hypolobocera buenaventurensis from Buenaventura, Bajo Anchicayá, Valle del Cauca, under the number CRBMUV 83076.Unfortunately, the carapace of this specimen was fragmented, and in the jar there was only available the left first male gonopod, which is illustrated in the present contribution (Fig. 1A-F).In addition, she also found the holotype of the species Hypolobocera olgaluciae.The left first gonopod was not found in the jar, but the right first gonopod was attached to the crab and it is herein illustrated (Fig. 2A-F).
When the first male gonopod of H. buenaventurensis (Fig. 1A-E) was compared with the one of H. olgaluciae (Fig. 2A-E), we found that most of the morphological features of both species overlap.However, there are some differences.a) the lateral lobe of both species is nearly semicircular, with crenulations on distal border; however, it is wider in H. olgaluciae than in H. buenaventurensis; b) both species present a prominent tuberculated crest, parallel to lateral lobe on the cephalic surface; however, in H. buenaventurensis the crest ends at some distance of the distal border of lateral lobe, whereas in H. olgaluciae it goes beyond the distal border of the lateral lobe; c) H. buenaventurensis exhibits a transverse tuberculated crest on the subdistal half of the cephalic surface; meanwhile, Nauplius H. olgaluciae shows a transverse ridge, instead of the tuberculated crest; d) the mesial lobe of both species is subtriangular in distal view; however, in H. buenaventurensis the external border is smooth, whereas in H. olgaluciae it is nearly sinuous; e) the mesocaudal projection of spermatic channel in H. buenaventurensis ends into rounded papilla without spinules on its base, meanwhile in H. olgaluciae it is semi-acute with 3 spinules on its base.
The morphological differences described above for the first male gonopod correspond to populational variations of the species, which do not alter the overall pattern of H. buenaventurensis.Likewise, the additional morphological characters of the carapace and third maxilliped (see Figs. 1F,  2F) are similar for both species.In conclusion, H. olgaluciae should be considered as a junior synonym of H. buenaventurensis.