Amazighopsidae

Garassino, Alessandro & Pasini, Giovanni, 2018, Amazighopsidae, a new family of decapod macruran astacideans from the late Cretaceous (Cenomanian-Turonian) of Gara Sbaa, Southeastern Morocco, Natural History Sciences 5 (1), pp. 11-18 : 12-13

Family Amazighopsidae nov.

Diagnosis: Carapace subcylindrical; triangular, short rostrum with serrate suprarostral margin, bearing 3-4 pairs of teeth; deep cervical groove strongly inclined forward, reaching the dorsal margin at the anterior third of the total carapace length (excluding rostrum); antennal groove short and weak; cephalic region shorter than branchial one; s1 short; s2 with subrounded pleura partially overlapping those of s1 and s3; s1, s3-s6 smooth with rounded pleurae; subrectangular telson without diaeresis and lateral margins with one median movable spine and two distal movable spines; chelate P1 with weak heterochely; uropodal exopod without diaeresis.

Type and included genus: Amazighopsis n. gen., by monotypy.

Etymology: From Amazigh that means Berber in the original language of this people.

Geological range: Late Cretaceous (Cenomanian-Turonian).

Discussion. Some morphological characters of the studied specimens, such as the dorso-laterally compressed carapace, the cylindrical shape of the carapace, and the strong chelate P1 allow us to assign them tentatively to the infraorder Astacidea , including all the marine chelate lobsters. Indeed the assignment to this infraorder is tentative because, according to Karasawa et al. (2013: 110), some other diagnostic characters, such as the rostrum with supra- and subrostral teeth, s2 larger than s3-s6, and the uropodal exopod with diaeresis do not fit with the characters of the studied specimens.

According to Karasawa et al. (2013: 94) the new classification for lobsters, after the phylogenetic systematics proposed by Scholtz & Richter (1995) and Wahle et al. (2012), includes two sections for the infraorder Astacidea Latreille, 1802 , as follows: Homarida Scholtz & Richter, 1995 and Astacida Scholtz & Richter, 1995. The former includes three superfamilies, Enoplometopoidea de Saint Laurent, 1988 ( Enoplometopidae de Saint Laurent, 1988 ; Uncinidae Beurlen, 1930 ); Stenochiroidea Beurlen, 1928 ( Stenochiridae Beurlen, 1928 ); and Nephropoidea Dana, 1852 ( Nephropidae Dana, 1852 ). The latter includes three superfamilies, Protastacoidea Albrecht, 1983 ( Protastacidae Albrecht, 1983 ); Astacoidea Latreille, 1802 ( Astacidae, Latreille, 1802 ; Cambaridae Hobbs, 1942 ; Cricoidoscelosidae Taylor, Schram & Yan-Bin, 1999 ); and Parastacoidea Huxley, 1879 ( Parastacidae Huxley, 1879 ), truly “ … poorly known in the fossil record. ” ( Karasawa et al., 2013).

Though the two sections have substantial morphological differences concerning the rostrum (short or elongate with supra- or subrostral teeth), the carina and groove system of the carapace, the pleon (pleurae more or less pointed or rounded), and the telson (with or without diaeresis), they share one constant and consistent diagnostic character, the uropodal exopod with diaeresis, according to the most recent phylogenetic systematics proposed by Karasawa et al. (2013).

Based upon the diagnoses proposed by Karasawa et al. (2013) for each family within the two sections, we point out that some morphological characters of the studied specimens, such as the strongly tuberculate carapace and P1; a short rostrum with serrate suprarostral margins, bearing 3-4 pairs of teeth; a deep cervical groove and a weak antennal groove not forming the characteristic “W” shape; s2 with subrounded pleura partially overlapping those of s1 and s3; smooth s1, s3- s6 with rounded pleurae; a subtrapezoidal telson without diaeresis and lateral margins with one median movable spine and two distal movable spines; chelate P1 slightly heterochelous (peculiar shape of the P1 chela: P1 index occlusal margin with a row of strong rounded teeth inclined forward and arranged randomly; P1 dactylus occlusal margin with a row of pointed, elongate, and slender teeth strongly inclined distally); and mainly the uropodal exopod without diaeresis, are so unique and peculiar that the studied specimens do not fit any diagnosis for known clawed lobster families, provided by the authors.

Therefore, these differences warrant a distinct family within the Astacidea to accommodate the type genus Amazighopsis n. gen.

The new family cannot be assigned to both sections of the infraorder Astacidea based upon the characters proposed by Karasawa et al. (2013: 110, 113). According to Holthuis (1991: 31-47; fig. 61), the new family may be, however, tentatively assigned to the section Homarida based upon Nephropsis Wood-Mason, 1873 , the sole genus within this section, including the extant species with or without a diaeresis on the uropodal exopod. Moreover, the lack of the diaeresis on the telson in the new family, a peculiar character of the Homarida, as proposed by Karasawa et al. (2013: 116) (vs. telson with diaeresis in Astacida), would further support the assignment of the new family to this section.