Amazighopsis cretacica, Garassino & Pasini, 2018

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 : 13

Amazighopsis cretacica n. gen., n. sp.

Figs. 1-6

Diagnosis: as for family.

Etymology: the trivial name alludes to the Cretaceous, the geological age of the studied specimens.

Holotype: MSNM i27545 .

Paratypes: MSNM i27546 , MSNM i27646 .

Type locality: Gara Sbaa (Kem Kem).

Material and measurements: three complete specimens, one of these (MSNM i27546) preserved as part and counterpart.

MSNM i27545 – tl: 45 mm; lcpx: 25 mm; wcpx: 12 mm; lp: 10 mm; wp: 7 mm; ldi: 8 mm

MSNM i27546 – tl: 65 mm; lp: 10 mm; wp: 7 mm; ldi: 9 mm

MSNM i27646 – lp: 10 mm; wp: 7 mm; ldi: 9 mm

Description. Carapace – Subcylindrical carapace strongly granular, laterally compressed; dorsal margin slightly convex; posterior margin nearly straight; triangular, short rostrum with serrate suprarostral margin, bearing 4-5 pairs of teeth; dorsal rostral surface concave without median carina; subrostral margin spineless; deep cervical groove nearly straight, strongly inclined forward, reaching the dorsal margin at the anterior third of the total carapace length (excluding rostrum), making an angle of about 45° to the dorsal margin; antennal groove short and weak; cephalic region shorter than branchial one; branchiocardiac, postcervical, and hepatic grooves absent; carapace surface without accessory spines. Pleon – s1 short, narrow; s2 with subrounded pleura partially overlapping those of s1 and s3; convex pleurae, slightly rounded ventrally, ending in a short point; tergites and pleurae of s1-s6 smooth; subtrapezoidal telson without diaeresis, and lateral margins with one median movable spine and two distal movable spines. Cephalic appendages – Cephalic appendages poorly preserved, flagella of antennulae and antennae partially preserved; antennae flagella stronger than those of the antennulae. Thoracic appendages – mpx3 and P2-P5 not preserved; P1 slightly heterochelous, with ischium, merus, carpus, and propodus strongly granulate; right P1 with squared ischium, subrectangular elongate merus, convex and serrate dorsally; stout subtriangular carpus with serrate dorsal margin; elongate subrectangular chela serrate dorsally, outer surface with two parallel longitudinal rows of strongly aligned tuberculate spines; right P1 chela with elongate dactylus and index, equal in length and curved distally; index slightly stronger than dactylus; index occlusal margin with a row of strong, rounded molariform teeth inclined distally and arranged randomly; dactylus occlusal margin, with a row of pointed, elongate, and slender teeth strongly inclined distally; left P1 propodus, merus, and carpus similar in shape and ornamentation of right P1; left chela poorly preserved, looks slightly stouter than the right with stronger index and dactylus, occlusal margins bearing a rim of similar rounded molariform teeth. Pleonal appendages – Pleopods poorly preserved; uropodal endopod and exopod as long as telson; uropodal endopod and exopod rounded posteriorly with one thin longitudinal median carina and spiny margins; uropodal exopod without diaeresis.

Figures

Fig. 1 - Amazighopsis cretacica n. gen., n. sp., MSNM i27545, Holotype. A) General view in natural light (x 1.51). B) General view in UV light (x 1.44).

Fig. 2 - Amazighopsis cretacica n. gen., n. sp., MSNM i27546, Paratype. A) General view in natural light (x 1.23). B) General view in UV light (x 1.12).

Fig. 3 - Amazighopsis cretacica n. gen., n. sp., MSNM i27646, Paratype. A) General view in natural light (x 2). B) General view in UV light (x 1.71).

Fig. 4 - Amazighopsis cretacica n. gen., n. sp., MSNM i27545, close-up of the telson without diaeresis and with movable spines on lateral margin (arrows) and uropodal exopod without diaeresis (x 6.81).

Fig. 5 - Amazighopsis cretacica n. gen., n. sp., MSNM i27546. A) Close-up of the carapace with the simple system grooves [cervical, (ee 1) and antennal (b) grooves] and short rostrum with serrate suprarostral margin (x 1.36). B) Close-up of P1 chela with the occlusal margins of dactylus and index (x 1.78).

Fig. 6 - Amazighopsis cretacica n. gen., n. sp. A) reconstruction. B) close-up of the occlusal margins of P1 chela.