Estimating diversity of Indo-Pacific coral reef stomatopods through DNA barcoding of stomatopod larvae

There is a push to fully document the biodiversity of the world within 25 years. However, the magnitude of this challenge, particularly in marine environments, is not well known. In this study, we apply DNA barcoding to explore the biodiversity of gonodactylid stomatopods (mantis shrimp) in both the Coral Triangle and the Red Sea. Comparison of sequences from 189 unknown stomatopod larvae to 327 known adults representing 67 taxa in the superfamily Gonodactyloidea revealed 22 distinct larval operational taxonomic units (OTUs). In the Western Pacific, 10 larval OTUs were members of the Gonodactylidae and Protosquillidae where success of positive identification was expected to be 96.5%. However, only five OTUs could be identified to species and at least three OTUs represent new species unknown in their adult form. In the Red Sea where the identification rate was expected to be 75% in the Gonodactylidae, none of four larval OTUs could be identified to species; at least two represent new species unknown in their adult forms. Results indicate that the biodiversity in this well-studied group in the Coral Triangle and Red Sea may be underestimated by a minimum of 50% to more than 150%, suggesting a much greater challenge in lesser-studied groups. Although the DNA barcoding methodology was effective, its overall success was limited due to the newly discovered taxonomic limitations of the reference sequence database, highlighting the importance of synergy between molecular geneticists and taxonomists in understanding and documenting our world's biodiversity, both in marine and terrestrial environments

Alometria no crescimento de Uca mordax (Smith) (Crustacea, Decapoda, Ocypodidae) na Baía de Guaratuba, Paraná, Brasil Allometric growth in the fiddler crab Uca mordax (Smith) (Crustacea, Decapoda, Ocypodidae) from Guaratuba Bay, Parana, Brazil

Um estudo do crescimento relativo da maior quela do macho e do abdome da fêmea foi realizado numa população do caranguejo chama-maré Uca mordax (Smith, 1870) ocorrente no extremo oeste da Baía de Guaratuba, Paraná, sul do Brasil. O comprimento da maior quela (CMQ) foi medido em 319 machos, e a largura do abdome (LAB) em 356 fêmeas. Adicionalmente, seis chama-marés sexualmente indiferenciados foram analisados. A largura da carapaça (LC) foi escolhida como dimensão de referência para ambos os sexos, a qual variou de 1,94 a 20,0 mm para machos, de 2,50 a 18,85 mm para fêmeas, e de 1,94 a 3,15 para os indivíduos sexualmente indiferenciados. A relação entre o LC e CMQ mostrou um ponto de inflexão em 11,70 mm LC nos machos, e entre LC e LAB, em 8,77 mm LC dentre as fêmeas. Os machos (média LC = 14,24 mm) atingiram tamanhos pouco maiores do que as fêmeas (média LC = 13,97 mm). O crescimento foi alométrico positivo durante toda a ontogênese de ambos os sexos, isto é, antes e depois da muda puberal. As equações das relações entre LC e CMQ nos machos foram: logCMQ = -0,542265 + 1,51.logLC para machos juvenis e logCMQ = -1,446281 + 2,37.logLC para machos adultos. Nas fêmeas, a relação entre LC e LAB foi: logLAB = -0,607282 + 1,22.logLC e logLAB = -0,912074 + 1,60.logLC, respectivamente, para juvenis e adultas. Estas dimensões estão relacionadas com as atividades reprodutivas da espécie. O nível de alometria do CMQ dos machos adultos de U. mordax foi o mais alto dentre as espécies do gênero, cujo crescimento relativo desta dimensão foi estudado. A proporção de machos destros foi estatisticamente a mesma daqueles sinistros (1:1).<br>Relative growth of the male major chela and female abdomen was studied in a population of the fiddler crab Uca mordax (Smith, 1870) from Guaratuba Bay, Parana, Southern Brazil. Major chela length (CMQ) was measured from 319 males, and abdomen width (LAB) from 356 females. Also six small sexually undifferentiated crabs were measured. Carapace width (LC) was the reference dimension for both sexes, which ranged from 1.94 to 20.0 mm for males, from 2.50 to 18.85 mm for females, and from 1.94 to 3.15 mm for sexually undifferentiated crabs. Relationship between LC and CMQ showed a transition point at 11.70 mm LC in males, and between LC and LAB, at 8.77 mm LC in females. Males (mean LC = 14.24 mm) showed a slightly greater size than females (mean LC = 13,97 mm). These dimensions had positive allometrical growth during all life for both sexes: before and after the puberal molting. Regressions between LC and CMQ in males read as: logCMQ = -0,542265 + 1,51.logLC for male juveniles and logCMQ = -1,446281 + 2,37.logLC for male adults. In females, the regressions between LC and LAB were: logLAB = -0,607282 + 1,22.logLC for juveniles and logLAB = -0,912074 + 1,60.logLC for adults. These body dimensions are related to reproductive activities of this species. The level of allometry in CMQ of adult males was the highest among Uca species which relative growth of this dimension is known. The handedness had a proportion of 1:1 between right-handed and left-handed males