Histological and histochemical characterization of the secretory cells of Choeradoplana iheringi Graff, 1899 (Platyhelminthes: Tricladida: Terricola)

Morphology of parenchymally implanted foreign bodies indicates copulatory wounding in a planarian

Traumatic mating, that is, copulation that involves wounding the partner's body, is a widespread phenomenon that is particularly prevalent in hermaphroditic animals. Traumatic mating is generally a collateral side effect of diverse strategies (from physical anchorage to injection of substances to manipulate the partner), but the trauma could also be adaptive by itself if it delays remating by the injured partner. In the Tricladida (the clade of planarian flatworms), reciprocal sperm transfer is often assumed to occur by means of a 'regular' nontraumatic copulation, that is, insertion of the penis through the partner's gonopore and deposition of the ejaculate into its genital atrium, with subsequent sperm migration to the oviducts. However, while studying the anatomy of Brazilian land planarians for taxonomic purposes, we found foreign bodies, reminiscent of spermatophores, implanted within the parenchyma of Choeradoplana albonigra (Riester, 1938). Herein, we describe and illustrate several lines of morphological evidence indicating that these foreign bodies likely represent a novel case of intragenital copulatory wounding (e.g., structural and histochemical similarity to land planarians spermatophores; implantation at the level of the gonopore; vestiges of rupture of the genital atrium's wall), corroborating that traumatic mating is pervasive and underreported in Metazoa. We also propose two different hypotheses to explain such copulatory wounding, viz., that it concerns (1) a regular mating strategy or (2) an accidental effect of the copulation. In any event, this land planarian may prove useful as a novel, noninsect terrestrial model organism to investigate the evolution of traumatic mating.

The alkaloid Ageladine A, originally isolated from marine sponges, used for pH-sensitive imaging of transparent marine animals

The brominated pyrrole-imidazole Ageladine A was used for live imaging of the jellyfish (jellies) Nausithoe werneri, the sea anemone Metridium senile and the flatworm Macrostomum lignano. The fluorescence properties of Ageladine A allow for estimation of pH values in tissue and organs in living animals. The results showed that Nausithoe werneri had the most acidic areas in the tentacles and close to the mouth (pH 4–6.5), Metridium senile harbours aggregates of high acidity in the tentacles (pH 5) and in Macrostomum lignano, the rhabdoids, the gonads and areas close to the mouth were the most acidic with values down to pH 5.

Estado do conhecimento dos macroturbelários (Platyhelminthes) do Brasil

Nas últimas décadas tem crescido o esforço internacional para conhecer a biodiversidade mundial visando a criação de políticas públicas de conservação. O Brasil vem participando deste esforço, como evidenciam as recentes publicações sobre o estado do conhecimento de vários táxons de organismos. Os macroturbelários (Polycladida e Tricladida, Platyhelminthes) fazem parte da fauna mundialmente menos estudada. Neste trabalho inventariamos por regiões a diversidade da fauna brasileira conhecida de macroturbelários e comparamos esta diversidade com a do resto do mundo. Analisamos também a atividade dos taxonomistas brasileiros do grupo no contexto mundial. Os resultados mostram que praticamente a totalidade das 246 espécies nominais descritas procede das regiões Sudeste e Sul. O número de espécies deverá aumentar significativamente quando forem feitas novas coletas, tanto em biomas e regiões ainda pouco ou nada explorados quanto nas áreas já amostradas. O Brasil está, relativamente a outros países, bem provido de especialistas. No entanto, em face da grande diversidade estimada, as amostragens deveriam ocorrer concomitantemente com a formação de novos especialistas.