Point of View Phylogeny of Scaphopoda (Mollusca) in the light of new anatomical data on the Gadilinidae and some Problematica, and a reply to Reynolds

Abstract

The class Scaphopoda comprises 500-600 Recent, purely marine species classified in the orders Dentaliida and Gadilida, with seven and five families respectively. Although the orders are anatomically well defined, family-level relationships are still poorly understood and little studied. Most systematic schemes (Pilsbry

The scaphopod foot is ventral: more evidence from the anatomy ofRhabdus rectius(Carpenter, 1864) (Dentaliida: Rhabdidae)

“…We have not reconstructed the pedal musculature in the present material, as the current study focused on the dorsal region above the foot complex. The banding of the dorso-ventral muscles in the abdominal region varies among different families, and the separation into two equal pairs of bands as confirmed here is a character shared by the families Rhabdidae, Dentaliidae, and Laevidentaliidae (Steiner 1998).…”

“…unpublished theses : Herbert 1986;Davies 1987). The class is clearly divided into two major orders, Dentaliida and Gadilida, consistently supported by both molecular phylogenetic results and substantial anatomical differences (Steiner 1998;Stöger et al 2013). Beyond this, comparisons of anatomical features are less common, but where more comprehensive comparative studies exist they do demonstrate interesting variability (e.g.…”

“…The dorso-ventral muscles traverse the long axis of the scaphopod body (Figure 2) from their attachment to a muscle ring at the ventral mantle margin near the foot, leading into the narrower part of the body (Steiner 1998), and these muscles run from the convex side to the concave side of the shell (from bottom left to top right in the schematic in Figure 2). The dorso-ventral muscles thus cross the body diagonally, meaning that either the long axis (top to bottom in Figure 2) or the short axis (left to right) could potentially be considered the dorsoventral axis.…”

A phylogenetic assessment of the branchiobdellidan family Branchiobdellidae (Annelida, Clitellata) using spermatological and somatic characters

“…Fig. 5B, Branchiobdella polyphyletic), although we are aware that the 'reweighting methodology' does expose us to 'the danger of few "good" characters (those for which homology decisions are correct) being overruled by quantitatively dominant characters with incorrect homology decisions' (Steiner 1998).…”

A commented list of Scaphopoda (Mollusca) found along the Brazilian coast, with two new synonymies in the genus Gadila Gray, 1847

“…The group currently comprises 565 valid species (Steiner & Kabat 2004, Caetano & Absalão 2005, Scarabino 2008, Scarabino & Caetano 2008, Gracia & Ardila 2009, Simone 2009) and had its classification recently discussed by Steiner (1992Steiner ( , 1998Steiner ( , 1999 and Scarabino (1995). Two orders were recognized at the end: Dentaliida and Gadilida.…”