Bothitrema bothi (MacCallum, 1913), a monopisthocotylean monogenean (Bothitrematidae) found on gills and occasionally on the olfactory rosette within the nares of the bothid flounder, Scophthalmus aquosus (Mitchill, 1815), is distributed along the Atlantic coast of the USA from Woods Hole, Massachusetts to Delaware Bay. This study details aspects of the morphology, microecology and biology of the oncomiracidium, juvenile and adult. Adult worms occur almost exclusively between rakers on the first and second gill arches while juveniles occupy secondary gill filaments. Analysis of variance revealed significant arch, side and position effects. Worm attachment and position is maintained largely by suction generated by a circular seal using its 54 radially arranged accessory haptoral sclerotised elements and a marginal valve. A small anterior appendix with two marginal hooks lies dorsal to a deep anteromedian cleft in the haptor, which, together with wall muscles, creates and releases the negative pressure required for attachment. Four pairs of gland openings in the ventrolateral margins of the anterior adhesive area produce secretions for attachment. Operculate eggs with four rounded protuberances and a filament are laid individually at four-minute intervals at 22ºC. Hatching occurs in five days at 20°C. Oncomiracidia have two pairs of eyes, with the posterior pair fused, show both positive and negative phototaxis and swim at a mean rate of 5.2 mm/s at 22°C. Larvae have a circle of 16 hooks and a pair of hamulus primordia. Other accessory haptoral sclerotised structures arise de novo in juveniles after attachment to the host. These data will help to resolve more clearly the relationships of the Bothitrematidae within the Monopisthocotylea.
Paussus favieri Fairmaire is one of only two species of the myrmecophilous carabid tribe Paussini known from Europe.
Larvae are known from only 10 of the 580 paussine species. As in many beetles with considerably modified later instar larvae, the
first instars represent a valuable source of informative characters for taxonomy and phylogenetic analyses (primary chaetotaxy, eggbursters, etc.). Therefore, the discovery of the first instar larva of P. favieri is particularly important, as it represents only the second
species for which this larval stage is known. In this paper we describe the behavior and morphology of the larval first instar of P.
favieri (subtribe Paussina of Paussini) and compare it with that of Arthropterus sp. (subtribe Cerapterina), which is the only other 1st
instar described in the Paussini. Most surprisingly, we found that the 1st instar of P. favieri lacks a prostheca, which was previously
thought to be a synapomorphy of Paussina + Platyrhopalina. Rather, P. favieri has a unique mandibular structure that seems to be
functionally analogous to the protheca. It is a long, broadly lanceolate, distinctly flattened structure apparently homologous to the
medial mandibular seta (MN2*), which arises from an area behind the cutting edge of mandible. We predict that the function of the
protheca and this similar structure in P. favieri are involved in a specialized feeding strategy that may include soliciting trophallaxis
from their host ants. We also report some observations of the first instar hatching from the egg, feeding on liquid and a behaviour we
interpret as a “calling behavior,” all of which were videotaped and posted on the Tree of Life Web Project.