Alcidellus

{{Automatic taxobox

| fossil_range = {{fossil range|Bathonian|Callovian|ref={{cite journal|last=Sepkoski |first=Jack |title=A compendium of fossil marine animal genera (Cephalopoda entry) | journal=Bulletins of American Paleontology |volume=363 |pages=1–560 | year=2002 | url=http://strata.geology.wisc.edu/jack/showgenera.php?taxon=231&rank=class |accessdate=2017-10-18 |url-status=dead | archiveurl=https://web.archive.org/web/20160225225905/http://strata.geology.wisc.edu/jack/showgenera.php?taxon=231&rank=class | archivedate=2016-02-25 }}}}

| taxon = Alcidellus

| authority = Westermann, 1958 }}

Alcidellus is an oxyconic (sharp ventered) haploceratacean ammonite from the Middle Jurassic.{{cite web | title= Paleobiology Database - Alcidellus |authorlink =| year = | url = https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=300433| access-date = 2017-10-19 }}

Alcidellus was named as a genus buy Gerd Westermann in 1958. It is now generally seen as a subgenus of Oxycerites, differing from Oxyceratites (O) in having a broader venter with ventrolateral shoulders. The shell of Oxycerites, including O (Alcidellus) is generally smooth, essentially involute with a small umbilicus, highly compressed with flanks converging on a narrow, somewhat sharp venter. Sutures are ammonitic.