Cretaceous Crocodyliforms from the Sahara Author Sereno, Paul University of Chicago, Chicago, United States of America Author Larsson, Hans Redpath Museum, McGill University, Montreal ,, Canada text ZooKeys 2009 2009-11-19 28 28 1 143 journal article 10.3897/zookeys.28.325 cac72c82-2c83-401f-b6d0-8afb5321fde3 1313–2970 576570 A979ECDE-871F-4AFC-9ABA-63A0FD6DC323 Laganosuchus maghrebensis sp. n. urn:lsid:zoobank.org:act: E5BCEEAD-DFEF-4EF6-AA62-110EF91FCD0F Fig. 42 Table 14 Etymology . Maghreb , western (Arabic); - ensis (Latin), from. Named for the area where the holotype was discovered in the Kem Kem Beds of southeastern Morocco . Holotype . UCRC PV2 ; anterior portion of the left dentary preserving four alveoli and one replacement tooth in the anteriormost tooth position ( Fig. 42 ). Referred material. CMN 50838 , anterior left dentary fragment preserving the symphyseal end and alveoli 1–3. Figure 42. Dentary fragment of the crocodyliform Laganosuchus maghrebensis gen. n. sp. n. Anterior end of the left dentary (UCRC PV2). A Left lateral view. B Medial view (reversed). C Dorsal view. D Ventral view. E Replacement tooth in first dentary alveolus in lingual view. Scale bar in A-D equals 3 cm; scale bar in E equals 1 cm. Abbreviations: ad1, 3 , alveolus for dentary tooth 1, 3; afo , alveolar foramina; asp , articular surface for the splenial; d1, 4, dentary tooth 1, 4; fl , fluting; fo , foramen; Mc , Meckel’s canal; rt , replacement tooth; sym , symphysis; tasp , tip of the articular surface for the splenial. Type locality. Er Rachidia District, Morocco (exact locality unknown). The referred specimen ( CMN 50838 ) probably was found south of Erfoud (Fig. 1A, B). Horizon . Kem Kem Beds, upper member; Upper Cretaceous (Cenomanian), ca. 95 Mya ( Sereno et al. 1996 ). Diagnosis . Metasuchian with a narrow, well defined groove on the ventral aspect of the anterior dentary immediately lateral to the splenial that arcs to the posterior aspect of the symphysis; shallow, anteriorly tapering trough on the anterior dentary just lateral to the more sharply defined groove. Dentary . The anterior portion of the dentary is preserved in two specimens of Laganosuchus maghrebensis . Th e very rugose dentary symphysis suggests that it may have fused with maturity, and that its size, which is somewhat smaller than Laganosuchus thaumastos , may not be significant. The more complete specimen ( Fig. 42 A-D) shows a remarkable similarity to Laganosuchus thaumastos . Both have slender U-shaped lower jaws with the symphysis restricted to the dentary, festooned alveoli with enlarged first and second teeth, and a sharply incised Meckel’s canal developed as a narrow groove. Th e teeth are also spikeshaped without recurvature or marginal ornamentation. Several differences, however, establish L. maghrebensis as a distinct species. The dentary is narrower near the symphysis ( Fig. 42C ), lacking the internal crest that thickens the dentary in L. thaumastos ( Fig. 38B ). Th e anterior alveoli in L. maghrebensis are not procumbent or exposed in lateral view as in L. thaumastos . Likewise, an articular scar for the splenial in L. maghrebensis shows that its anterior end tapers to a narrow tip along the ventral margin ( Fig. 42B ) in contrast to the bifurcated flanges in L. thaumas- tos ( Fig. 38B ). Th e incised groove representing Meckel’s canal is located on the ventral, rather than lingual, aspect of the dentary ( Fig. 42D ). Table |4. Dimensions (mm) of the anterior end of the right dentary of Laganosuchus maghrebensis (UCRC PV2).

Structure Dentary	Measurement Symphysis, dorsoventral height Symphysis, maximum anteroposterior width Dentary ramus between alveolus 2 and 3, dorsoventral height Dentary ramus between alveolus 2 and 3,transverse width	Length 25.5 14.6 19.1 11.4
Alveolus 1	Maximum mesiodistal length Maximum labiolingual width	10.1 6.4
Alveolus 2	Maximum mesiodistal length Maximum labiolingual width	7.3 5.0
Alveolus 3	Maximum mesiodistal length Maximum labiolingual width	6.4 4.0
Alveolus 4	Maximum mesiodistal length Maximum labiolingual width	11.9 5.7
Crown d1	Replacement crown, height Replacement crown, mesiodistal width of base	12.2 5.3

Although crown size in the two species is very similar, the alveolus of the caniniform tooth (d4) is slightly larger than comparable measurements for d1 (Table 14), the reverse of the condition in Laganosuchus thaumastos (Table 13). L. maghrebensis , in addition, shows low fluting on the lingual aspect of the crown of the first dentary tooth ( Fig. 42E ). A comparable crown, however is not available at the anterior end of the dentary series in L. thaumastos .