Sigmer Quiroga

When names are wrong and colours deceive: unravelling the Pseudoceros bicolor species complex (Turbellaria: Polycladida)

The polyclad Pseudoceros bicolor derives its name from a distinctive two-coloured dorsal colouration, which consists of a very dark, almost black central area with acute black lobes extending towards a translucent greyish margin. At least three different colour morphs have been described, ranging from a pale speckled brown through an evenly dark brown form, to a morphotype resembling the original species description. Pseudoceros aureolineatus is easily confused with the light brown colour morph of P. bicolor, and P. rawlinsonae resembles both P. bicolor and P. aureolineatus. Using morphological characters of newly collected specimens and nucleotide sequences of the 28S ribosomal DNA gene, the taxonomic validity of P. rawlinsonae and P. bicolor is confirmed and the descriptions of their colouration are emended. The new subspecies, P. bicolor marcusorum subsp. nov. is erected, the genus Cryptoceros is eliminated, and the new combination Maritigrella aureolineata comb. nov. (Euryleptidae) is established for P. aureolineatus.

Evolution of flatworm central nervous systems: Insights from polyclads.

The nervous systems of flatworms have diversified extensively as a consequence of the broad range of adaptations in the group. Here we examined the central nervous system (CNS) of 12 species of polyclad flatworms belonging to 11 different families by morphological and histological studies. These comparisons revealed that the overall organization and architecture of polyclad central nervous systems can be classified into three categories (I, II, and III) based on the presence of globuli cell masses -ganglion cells of granular appearance-, the cross-sectional shape of the main nerve cords, and the tissue type surrounding the nerve cords. In addition, four different cell types were identified in polyclad brains based on location and size. We also characterize the serotonergic and FMRFamidergic nervous systems in the cotylean Boninia divae by immunocytochemistry. Although both neurotransmitters were broadly expressed, expression of serotonin was particularly strong in the sucker, whereas FMRFamide was particularly strong in the pharynx. Finally, we test some of the major hypothesized trends during the evolution of the CNS in the phylum by a character state reconstruction based on current understanding of the nervous system across different species of Platyhelminthes and on up-to-date molecular phylogenies.

Echiniscidae from the Sierra Nevada de Santa Marta, Colombia, new records and a new species of Bryodelphax Thulin, 1928 (Tardigrada)

Abstract Three species of Echiniscus are recorded for the first time from Colombia: Echiniscus dariae, Echiniscus kofordi, and Echiniscus perarmatus. In addition, the description of the new species Bryodelphax kristenseni sp. n., is mainly based on the presence of ten paired plus two unpaired granularly sculptured ventral plates, the dorsal plate ornamentation with superficial irregular pores, no spine on the anterior legs, and the hind legs without papillae or dentate collar.

Códigos de barras genéticos en una especie de Paramacrobiotus (Tardigrada: Parachela) en Santa Marta, Colombia

espanolDebido a la gran cantidad de especies y a las dificultades en su identificacion morfologica, muchos estudios taxonomicos actuales de tardigrados se basan en el uso de tecnicas geneticas y moleculares. En Colombia son necesarios estudios enfocados en esta disciplina que permitan complementar la informacion morfologica; por consiguiente se analizaron siete secuencias del gen COI en el genero de tardigrado Paramacrobiotus de la cuenca baja del rio Manzanares, en Santa Marta, y se compararon con las secuencias del mismo genero presentes en la base de datos de GenBank a traves de un analisis de divergencia especifica y analisis de vecino mas cercano (NJ). Las secuencias obtenidas en el estudio mostraron una clara diferenciacion de las secuencias de GenBank y una baja distancia intraespecifica, obteniendose el codigo de barras genetico correspondiente a una sola especie. Las diferencias de los resultados con el analisis morfologico reflejan la eficacia de tecnicas moleculares como los codigos de barras y evidencian la importancia de la integracion de tecnicas moleculares a los estudios taxonomicos de los tardigrados. EnglishBecause of the great number of species and troubles with their morphological identification, many current taxonomic studies in tardigrades are based on the use of genetic and molecular techniques. In Colombia, studies focused in this discipline are needed to be able to complement the morphological information; consequently, seven COI gene sequences were analyzed in the genus of tardigrade Paramacrobiotus at the lower basin of the Manzanares River, in Santa Marta, and were compared with the sequences of the same genus present in the GenBank database through an analysis of specific divergence and neighbor-joining (NJ). The sequences obtained in the study showed a clear differentiation of the GenBank sequences, while at the same time showed a low intraspecific distance, obtaining a DNA barcoding for a single species. The differences obtained in comparison with the morphological analyses reflect the effectiveness of molecular techniques such as barcoding, emphasizing the importance of integration of molecular techniques to taxonomic studies on tardigrades.

Figure 18. Cycloporus Spp. Feeding. A In Taxonomy Of Cotylea (Platyhelminthes: Polycladida) From Cabo Frio, Southeastern Brazil, With The Description Of A New Species

FIGURE 18. Cycloporus spp. feeding. A. Cycloporus variegatus over orange ascidian; B. C. variegatus (MNRJ-PLAT 68) over ascidians, showing settling of a different species from the species previously grazed; C. C. variegatus over yellowish sponge, photo: Luiz Fernando Cassino; D. Symplegma rubra with feeding marks where a Cycloporus was collected; E. Cycloporus sp. over S. rubra; F. Cycloporus gabriellae with orange ascidian. as: ascidian; sp: sponge; fm: feeding marks; pl: polyclad; sy: Symplegma rubra.

Figure 3. Thysanozoon Brocchii. A In First Records Of Pseudocerotidae (Platyhelminthes: Polycladida: Cotylea) From Patagonia, Argentina

FIGURE 3. Thysanozoon brocchii. A, dorsal view of live specimen. B, ventral view of live specimen. Arrow heads show male gonopores.

Figure 2. Phrikoceros Mopsus. A In First Records Of Pseudocerotidae (Platyhelminthes: Polycladida: Cotylea) From Patagonia, Argentina

FIGURE 2. Phrikoceros mopsus. A, diagram of dorsal view. B, ventral morphology. C, dorsal view of pseudotentacles. D, ventral view of pseudotentacles. E, sagittal reconstruction of genital system portion. bl: black line; ce: cerebral eye; de: dorsal eyes of the pseudotentacle; fg: female gonopore; g: cement glands; m: mouth; mg: male gonopore; p: pharynx; su: sucker; s: stylet; sv: seminal vesicle; v: vagina; ve: ventral eyes of the pseudotentacles.