Trunk scales lozenge-shaped, generally flattened and elongate with an anterior basal prong up to third scale length; crown high, relatively narrow and rounded anteriorly with a wide flat neck region; high median section flanked with one or more lateral ridges ending in three to five separated posterior points and at least three postero-ventral ribs below them and anteriad
to the posterior basal rim; up to nine lateral lappets with an odd number on each side of scale.
Three pairs of ifr, anterior one minute, 2nd and 3rd pairs of medium length (0.08 mm), the posterior pair is anteriad
of anterior fr-orb.
Pronotum: Much wider than long, strongly declivous anteriorly; anterior collar distinctly developed, delimited posteriorly by a deep transverse furrow, lateral portions thickened; lateral margin narrowly explanate, not projecting anteriad
and ventrad, but distinctly elevated dorsad around its middle, distinctly emarginated anteriad
of humeri in dorsal view; humeral angle rounded, obtuse, distinct; posterolateral angle very broadly rounded, obsolete (Figs.
Additionally, in the Recent sample available (in both ROM Mammalogy and Palaeobiology), the anteriad
curvature of the anterior enamel portion of each buccal bay suggests Lemmus, as this enamel portion is straighter in both Synaptomys species.
TEXTURE: Impunctate, polished, callosite region of pronotum and corium anteriad
to orangish brown marking, shagreened.
Epigynum with flask-shaped atrium and narrow, essentially straight median septum; septum widening abruptly at anterior and posterior extremities; atrial sclerites distinct, diverging anteriad
; spermathecae with two swellings.
Indeed, Bickel (1996: 1168) considered Asyndetus and Cryptophleps as sister taxa based on apomorphic wing characters: "Costa ends at [R.sub.4 + 5], well before wing apex" and "vein M with bend or weakening in the distal third of wing, with distal section of M either weakly joined to its base, or distinctly displaced anteriad