SeveralSynalpheusspecies have been reported as hosts of bopyrid parasites; however, the impact of infestation on egg production is still unknown. Therefore, the present work studied reproductive aspects and the effect of parasitism on fecundity of the alpheid shrimpSynalpheus yanofrom Bocas del Toro, Caribbean coast of Panama. Un-infested females (N = 84) ranging from 3.7 to 9.6 mm carapace length, produced between 5 and 246 eggs (average: 98±64.6), and egg number increased significantly with female size. The eggs were relatively large (0.6–1.3 mm in diameter), but within the range of otherSynalpheusspecies, and egg size did not differ significantly between un-infested and infested females. Despite these large eggs, the morphological characteristics of hatching larvae indicate a planktotrophic development. During the incubation period, the egg volume increased from 0.100 to 0.218 mm3, representing an overall increase of 118%. A total of 18 females (16% of all ovigerous individuals) were infested, and the occurrence of parasitic infestation was more pronounced in larger females. Infested females ranging from 4.6 to 9.4 mm carapace length, produced between 22 and 166 eggs (average: 81±44.4). Egg-bearing females infested by parasitic bopyrids carried on average 41% fewer eggs than similar-sized females without parasites. The co-occurrence of parasites and developing eggs, however, indicates that the bopyrid parasite does not necessarily castrate its host. Therefore, we encourage more comparative intraspecific studies on egg production in infested and un-infested females to assess the impact of infestation on fecundity in caridean shrimp.

Based on an updated checklist of the benthic caridean shrimp fauna of the Eastern Tropical Pacific (ETP), we analyzed their large-scale species richness distribution patterns using a grid approximation. Caridean fauna is composed of 183 species belonging to 67 genera and 18 families. Alpheidae, Palaemonidae and Thoridae contributed largely to species richness. Alpheus and Synalpheus were the most diverse genera. Most species (24%) have a narrow distribution inhabiting a single grid, and as many as 135 are restricted to < 5 grids. Mexico has the largest richness (130) besides Ecuador (98) and Panama (75). Richness among grids varies largely; overall, it is larger around Galapagos and Panama, Colombia, Costa Rica and the Gulf of California. There was a meaningful correlation between a proxy of sampling intensity and richness, suggesting that along with habitat heterogeneity or large-scale evolutionary processes currently invoked as richness drivers, the pattern can also be related to differences in research efforts. Exponential fitting and Chao2 index suggest that the caridean faunal inventory from the ETP is still far from being complete. Overall, the results call for a more thoughtful and systematic sampling scheme in order to get information from poorly sampled environments and areas in the ETP.

S h o r t C omm u n fi c a t fi o n A n ew r e c o r d o f H a r l e q u fi n S h r fim p (M a l a c o s t r a c a : D e c a p o d a : P a l a em o n fi d a e : H ym e n o c e r a p fi c t a D a n a , 1 8 5 2 ) fi n t h e s o u t h e r n M e x fi c a n P a c fi f fi c R e e f s Om a r V a l e n c fi a -M e n d e z , A n d r e s L o p e z -P e r e z , B e t e l M a r fi n e z -G u e r r e r o , V fi r g fi l fi o A n t o n fi o -P e r e z & E d u a r d o R am fi r e z -C h a v e z 2 6 A u g u s t 2 0 1 7 | V o l . 9 | N o . 8 | P p . 1 0 5 7 1 -1 0 5 7 6

New records are provided for four species of caridean shrimp (Alpheidae and Palaemonidae) from Sonora, Sinaloa, and Oaxaca, along the west coast of Mexico. Alpheus tenuis Kim & Abele, 1988 extends its northern range to Puerto Peñasco, Sonora. Alpheus martini Kim & Abele, 1988 is recorded for the first time outside of Panama (Alcatraz Island, Sonora). Pontonia simplex Holthuis, 1951 is recorded from Teacapan, Sinaloa, in the pen shell Atrina maura (Sowerby, 1835), which constitutes a new host record; additionally, its live colour pattern is described. The range of Pontonia margarita Smith, 1869 is extended along the Mexican coast south to Oaxaca.