Pachychilus indiorum, (MORELET, 1849)

Strong, Ellen E., 2011, More than a gut feeling: utility of midgut anatomy in phylogeny of the Cerithioidea (Mollusca: Caenogastropoda), Zoological Journal of the Linnean Society 162 (3), pp. 585-630 : 607

PACHYCHILUS INDIORUM (MORELET, 1849)

Material examined

Mexico: Palenqué ( AM C.324125).

Description

Marginal fold S-shaped ( Fig. 14A ), terminating at posterior tip of sorting area; oesophageal aperture at tip of marginal fold recurved segment; sorting area highly curving, broad anteriorly, tapering rapidly to pointed tip; left margin of sorting area even, lacking conspicuous bulge; paired crescent-shaped pads bordering left margin of sorting area; pads broad, flattened, with thick, even ribbing across surface; accessory marginal fold extending posteriorly from tip of outer crescentic pad, bordering posterior margin of sorting area, with bifurcate posterior tip, continuing to posterior end of gastric chamber; sorting area pad lacking; proximal glandular pad long, tall, narrow, extending posteriorly obliquely across gastric chamber floor towards left from gastric shield; distal pad tapering rapidly, continuing transversely across midgut floor towards right to shallow depression at left posterior end of gastric shield; single digestive gland duct opening at left of glandular pad; crescentic ridge long, extending from digestive gland duct, curving in broad arc around glandular pad, separated by broad, shallow crescentic groove, joining distal tip of glandular pad behind gastric shield; accessory pads, caecum, and caecal folds lacking; U-shaped fold present below style sac aperture; typhlosoles unfused.

Figures

Figure 14. Midgut anatomy of Pachychilidae. A, Tylomelania abendanoni (MNHN). B, Tylomelania palicolarum (MNHN). Scale bars: 1.0 mm; refer to the text for a list of anatomical abbreviations.