Material and measurements: One nearly complete specimen in ventral view. MSNM i29337 – lcxp: 14 mm; wcxp: 10 mm; la: 130 mm; lb: 25 mm.

Description: Carapace. Carapace poorly preserved, subrectangular, longer than wide, with concave posterior margin; frontal margin poorly preserved, rostrum indistinct; pterygostomian regions with irregular coarse granulations; epistome smooth, with a median frontal triangular projection. Pleon. Pleonal somites s1-s6 subrectangular; pleurae not visible; s1-s6 decreasing posteriorly (s1 = 9 mm; s6 = 6 mm); telson poorly preserved, downturned posteriorly under the body. Thoracic sternum. Smooth sternum flattened, triangular-shaped, isosceles, decreasing in size distally. Cephalic appendages. Thick antennae, with very elongate flagellum, decreasing in size distally; strong peduncle with 3 well-developed spinose articles; antennae about 4.3 times longer than body; antennulae slender, elongate (12 mm total length), 11 times shorter than antennae; proximal elongate slender peduncle 3 times longer than the distal one, with smooth lateral margins; distal short slender peduncle, with smooth lateral margins; two unequal flagellae shorter than the peduncle; outer flagellum short and wide, subtruncate; inner flagellum elongate and thin, decreasing in size distally; scaphocerite absent; Mxp3 elongate with distal triangular dactylus. Thoracic appendages. P1–P5 well exposed, covered by granulate, coarse ornamentation; P1–P3 having same length; P1 with strong merus, carpus, and globular elongate propodus; strong triangular P1 dactylus slightly downturned, with a medial longitudinal groove; P1 twice times wider in transverse section (2 mm) than P2–P3; P2–P3 elongate and more slender (1 mm) than P1, ending in a pointed triangular dactylus; P4–P5 much thinner (0.5 mm) and shorter than P2–P3, with triangular pointed dactylus and decreasing in length posteriorly; P1–P3 covered by coarse irregular granulations on merus, carpus, and propodus; P4-P5 smooth. Pleonal appendages. Pleopods poorly preserved; uropodal exopod only partially exposed; petal-like exopod with a longitudinal thin medial ridge and subtruncate posterior margin; uropodal endopod poorly preserved, seems to have a thin longitudinal medial ridge.

Discussion: Despite the small body, we can confidently exclude that the studied specimen could represent a pre-adult or an “intermediate transitional development stage” sensu Haug & Haug (2016) due to the presence of a well-sclerotized hardened and developed pleon and the absence of the typical biramous elongate pleopods with plumose natatory setae on the pereiopods. Indeed, it's almost impossible to recognize in fossil spiny lobsters the intermediate development stages simply based upon the size or the generic body morphologic characters only (see for example the case of “Palinurina” tenera in Haug & Haug 2016) and when lacking an enough number of comparable specimens. Indeed, palinurid puerulus transitional stage (= benthic juvenile development) usually resembles the adult body plan.

Based upon Schweitzer et al. (2015) the diagnostic characters of the studied specimen fit those of the Palinuridae in having subcylindrical or semirectangular carapace; epistome in broad contact with carapace; broad, triangular sternum; very large antennae, thick antennal bases usually with spines; scaphocerite absent; P1 almost always same length or only slightly longer than other pereiopods.

According to Schweitzer et al. (2015), the Palinuridae includes 15 fossil and extant genera. The best-preserved characters of the studied specimen have been compared with those of the genera having more affinities in the body arrangement and P1 structure and shape.

The studied specimen clearly differs from Jasus Parker, 1883 in having shorter antennae, longer antennulae, and developed pleonal somites with spiny pleurae; Justitia Holthuis, 1946 in having carapace with imbricate scales and longer P1 subchelate, not distinctly wider than others; Panulirus White, 1847 in having antennular flagellum longer than peduncle, smooth P1 not enlarged, and spiny pleurae margin (Holthuis 1991; Schweitzer et al. 2015).

The studied specimen shows instead closer similarities with the extant and fossil genera Palinurus Weber, 1795 (Upper Cretaceous–Recent), Palinurellus von Martens, 1878 (late Eocene–Recent), and with the fossil Palinurina Münster, 1839 Lower–Upper Jurassic). However, Palinurus has a carapace and P1-P5 ornamentation nearly smooth and notably spiny pleurae margin, whereas Palinurellus has a larger body, P1 shorter than the others, uniformly covered by small tubercles, and shorter antennae (Schweitzer et al. 2015).

The studied specimen shares some diagnostic characters with Palinurina in having antennae with strong articles; absence of scaphocerite; and P2–P5 long and slender (Schweitzer et al. 2015: 6). However, the studied specimen differs from the type species, Palinurina longipes Münster, 1839, in several specific characters, such as the ornamentation with coarse irregular granulations of the pterygostomian region; P4–P5 smooth, distinctly much thinner and shorter than P2–P3; P1–P3 with fine irregular granulations not ranged in rims. We consider these substantial differences (beyond the different geological age), enough to exclude the assignment of the studied specimen to Palinurina.

In conclusion, we prefer to leave the studied specimen in open nomenclature due to the impossibility to check the main morphological characters of the carapace. This new report is remarkable, representing the second record of a representative of a spiny lobster in Africa, enlarging our knowledge on the decapod crustacean assemblage from the Late Cretaceous Gara Sbaa fossiliferous beds.