Type species: Ranina propinqua Ristori, 1891.

Included fossil specie s: Tethyranina propinqua (Ristori, 1891).

Type material: Holotype, MPUR i.543, from the Early Pleistocene of Città della Pieve (Perugia, Umbria, central Italy).

Additional material: MUSNAF 7075 and MSNM i28012 from the Early Pleistocene of Fabro Scalo and Orzalume-Cottano (Terni, Umbria, central Italy), respectively; MSNM i27876, from the Late Pleistocene of Trumbacà (Reggio Calabria, Calabria, southern Italy); MTPA 13468 (male), from the Early Pleistocene of the surrounding of Orvieto (Terni, Umbria, central Italy) (lchp: 26 mm; lcxp: 55 mm; ldct: 20 mm; wchp: 18 mm; wcxp: 45 mm; wf: 35 mm; wpm: 18 mm).

Stratigraphic range: Pasini & Garassino (2015: 50, Fig. 1A) briefly reported one incomplete frog crab (left anterolateral margin only) from the ‘Pliocene sands’ of Rapolano (Siena, Tuscany) tentatively assigned to Ranina as Ranina sp. However, the specimen cannot belong to Ranina Lamarck, 1801 due to the first anterolateral spine bifid and second trifid, diagnostic characters of Tethyranina Pasini & Garassino, 2018. Unfortunately, the specimen is very poorly preserved, lacking other characters useful to allow a closer precise assignment. The specimen represents the sole report known to date from Tuscany and it could be the oldest report of Tethyranina postdating to the Pliocene its presence in the Tyrrhenian Sea area. Since we are unable to confirm the systematic assignment of Ranina sp. to Tethyranina, the stratigraphic range of this genus is formally restricted to the Early to Late Pleistocene of Italy.

Remark: Pasini & Garassino (2018: 8) provided a diagnosis of Tethyranina propinqua based upon female specimens only. The additional peculiar features preserved in the studied male specimen allows an updated diagnosis including also the gender dimorphic characters.

Emended diagnosis [mainly based on MTPA 13468 (male) and MPUR i.543 and MUSNAF 7075 (females)]: Carapace subovate, wider anteriorly, narrowing posteriorly; wide, straight fronto-orbital margin in male (vs convex in female); dorsal surface with triangular spiny tubercles uniformly arranged; short pointed triangular rostrum downturned distally (vs narrower, longer in female); triangular inner-orbital spines; flat, subtriangular supraorbital spines, directed forward; bifid, rimmed extra-orbital spines with rimmed inner pointed straight tip longer than the other having an outer convex margin; convex, short anterolateral margins with two wide, strong spines; elongate, bifid first anterolateral spine with rimmed margins, pointed frontally (vs reduced, oblique to the middle longitudinal axis in female); wide, trifid second anterolateral spine with rimmed margins, pointed distal tips curved frontally (vs shorter second anterolateral spine with reduced pointed distal tips curved frontally in female); wide P1 with large chela (vs less developed and strong in female); triangular pleon with s1 wider than others in male (vs broader, rounded pleon with s1 narrower than others in female).

Description: Carapace – Elongate, subovate carapace longer than wide, wider anteriorly, narrowing posteriorly (Fig. 1A) (vs curved, convex in female – Fig. 1B); pointed rostrum, with triangular short distal tip downturned (vs narrower, longer in female); straight orbitofrontal margin with three spines bounded by two open fissures; short, curved inner-orbital spines; subtriangular supra-orbital spines; bifid extra-orbital spines longer than rostrum, marked by narrow fissure behind inner and outer tips; extra-orbital spines with rounded external margin and inner longer spine directed forward (extra-orbital spines more developed and longer in male than in female); short, convex anterolateral margins with a bifid first spine and trifid second spine (Fig. 2A) (vs bifid first anterolateral spine shorter, weakly projected frontally, creating a more rounded, convex anterior frontal margin in female – Fig. 2B); trifid second anterolateral spine directed forward with a long anteriorly pointed first tip (Fig. 2A) (vs less wide and shorter in female – Fig. 2B); granulated posterolateral margins converging to narrow posterior margin; almost straight, granulated posterior margin, finely rimmed; dorsal carapace ornamentation usually with spiny, flattened, and triangular tubercles, directed forward sometimes paired, mostly assembled at level of postfrontal margin or rounded and small at level of extra-orbital spines (female seem to have big spiny tubercles more uniformly arranged); frontal region with sparse rounded small tubercles; dorsal regions and grooves indistinct. Thoracic appendages – P1, P4 and P5 left pereiopods well preserved; large, subrectangular P1 merus and P1 carpus with flattened inner margin and convex outer margin; outer margin of P1 merus with transverse parallel serrate lines; one blunt spine directed upward on the upper margin of P1 merus; flattened P1 carpus shorter than P1 merus with parallel transverse striae on outer margin and at least one pointed spine distally; stout, wide P1 homochelous with large chela in male (Fig. 2C) (vs less wide palm and slender dactylus in female – Fig. 2D); large P1 chela with elongate, flat, and subrectangular palm; outer surface with transverse interrupted serrate lines and tubercles; upper margin of P1 palm with two median and distal spines, the second longer; deep, concave submedian rounded notch to accommodate upper marginal tubercle P1 carpus; lower margin of P1 chela with a row of five triangular, flat spines directed forward; subtriangular, pointed P1 index with transverse granulations; upper margin of P1 dactylus with a row of spinules or teeth; long, curved, and pointed P1 dactylus downturned; occlusal margins of P1 dactylus and index with at least five triangular teeth (as preserved – occlusal teeth of P1 index stronger than those of P1 dactylus) (Fig. 2C); P2, P3 not preserved; P4 and P5 well-preserved, modified to be the swimming/digging legs, both are flattened transversally, broad with narrow paddle-like shaped dactylus with pointed tip, more elongate and leafed in P5; stout, short rectangular P4 and P5 meri; triangular, knee-shaped P4 and P5 carpi, wider in P5, with a subrectangular propodus; P4 and P5 meri, carpi, and propodi with transverse lines running from upper to lower margins (Fig. 2E). Pleon (male) – s1–s4 partially preserved, slightly translated; narrow, subtriangular pleon narrowing posteriorly (Fig. 3A) (vs broader, rounded pleon with gently convex lateral rounded bracket-shaped margins in female – Fig. 3B); subtrapezoidal s1 wider than s2–s4 (s5, s6 poorly preserved) (Fig. 3A) (vs subrectangular s1 narrower in female – Fig. 3B); subrectangular s2–s4 decreasing posteriorly; smooth s1–s4 with raised axial carina.

Telson, pleonal appendages, telson, and ventral parts not preserved.