1. Introduction

Neogene shallow marine lithostratigraphic units are found at the San Jacinto Fold Belt (SJFB), mainly at the Luruaco anticlinorium, placed between Cartagena de Indias and Barranquilla (N Colombia), where fossiliferous horizons include abundant mollusks, reported by several authors (^{Pilsbry and Brown, 1917}; ^{Anderson, 1927}, ¹⁹²⁹; ^{Weisbord, 1929}). Recently, more detailed stratigraphic and paleontological reports indicate a more precise age and defined paleoenvironments (^{Pineda-Salgado et al., 2013}). This is the first record of Neogene crustaceans from the Colombian Caribbean. Most of the crustacean specimens have a good preservation, including both isolated articles and articulated carapaces, some with fine details of the cuticle. The most abundant crustaceans are callianassoids and portunoids.

2. Material

The study specimens are deposited in the Paleontological Collection of the Universidad Nacional de Colombia, Facultad de Ciencias, Departamento de Geociencias, Bogotá D.C., Colombia, under catalog numbers UN-DG-CR.

Systematic order is mainly based on de Grave et al. (²⁰⁰⁹).

3. Systematic paleontology

Order Decapoda ^{Latreille, 1802}

Infraorder Axiidea de ^{Saint Laurent, 1979}

Superfamily Callianassoidea ^{Dana, 1852}

Family Callianassidae ^{Dana, 1852}

Figure 3.1

Description. Merus elongated, semirectangular, with sharp longitudinal keel on outer surface; carpus narrow, one-third the length of carpus, smooth outer surface; propodus semirectangular, as high as carpus. The specimens are incomplete to offer a more specific identification.

Material. Two incomplete left chelipeds, UNDG-CR-033 and UN-DG-CR-034. Tubará Formation, Upper Miocene-Pliocene.

Measurements. UN-DG-CR-033, length = 33.2 mm, height = 14.2 mm; UN-DG-CR-034, length = 35.4 mm, height = 16.8 mm.

Comments. Callianassidae remains are reported from the middle to Late Miocene of Panama (^{Rathbun, 1918}).

Genus Neocallichirus^{Sakai, 1988}

Neocallichirus scotti (^{Brown and Pilsbry, 1913})

Figure 3.2, 3.3

Description. Right propodus subquadrate, upper and lower margins slightly divergent distally, dorsal and ventral margins smooth, outer surface finely granulated, inner surface smooth; fixed finger elongated, half the length of propodus.

Material. One right propodus, UN-DG-CR-035. Tubará Formation, Upper Miocene-Pliocene.

Measurements. UN-DG-CR-035, left propodus length = 18.2 mm, height = 15.5 mm.

Comments. Right propodus subquadrate, dorsal and ventral margins slightly divergent distally are features that suggest affinity of the Colombian specimens to Neocallichirus scotti, reported also from the Miocene of Panama (Culebra and Gatun formations) (^{Rathbun, 1919}).

Subfamily Callichirinae ^{Manning and Felder, 1991}

Genus Glypturus^{Stimpson, 1866}

Glypturus toulai (^{Rathbun, 1919})

Figure 3.4 - 3.13

Description. Merus subovate, with serrate lower margin; propodus nearly as long as high, serrated ventral margin, traces of spines on dorsal margin, inner and outer surfaces smooth, outer portion of anterior margin bears few small tubercles; fixed finger short, with sharp ridge on posterior portion; left dactylus with few tubercles on proximal portion, serrated on distal portion of occlusal surface.

Material. Three left propodi (one includes merus), two right propodi and one left dactylus, UN-DG-CR-036 to UN-DG-CR-041. Tubará Formation, Upper Miocene - Pliocene.

Measurements. UN-DG-CR-036, left propodus length = 18.2 mm, height = 15.5 mm; UNDG-CR-037, right propodus length = 17.7 mm, height = 14.6 mm; UN-DG-CR-038, right propodus length = 19.8 mm, height = 11.5 mm; UNDG-CR-039, left propodus length = 19.2 mm, height = 12.5 mm; UN-DG-CR-040, left propodus length = 20.1 mm, height = 10.3 mm; UNDG-CR-041, left dactylus length = 12.5 mm, height = 5.1 mm.

Comments. Propodus serrated ventral margin and traces of spines on dorsal margin, suggest affinities of the new specimens with Glypturus toulai (^{Rathbun, 1919}), which is reported from the Lower to Upper Miocene of Panama (Culebra and Gatun formations, respectively) (^{Rathbun, 1919}; ^{Todd and Collins, 2005}; ^{Hyžný et al., 2013}; ^{Klompmaker et al., 2016}).

Infraorder Anomura ^{MacLeay, 1838}

Superfamily Paguroidea ^{Latreille, 1802}

Family Diogenidae ^{Ortmann, 1892}

Genus Petrochirus^{Stimpson, 1858}

Petrochirus bouvieri^{Rathbun, 1919}

Figure 3.14 - 3.19

Description. Left and right chelae covered by strong tubercles; right chela as long as left chela but twice its height; right propodus curved, dactylus triangular, with short spines on dorsal surface, covered by strong multituberculated ornament, occlusal surface covered by strong granules of diverse size, fixed finger two-thirds the length of dactylus, covered by strong multituberculated ornament; left propodus slightly inflated, propodus slightly shorter than fixed finger, dactylus as long as fixed finger, both densely ornamented with multituberculated granules.

Material. One left propodus, one right dactylus and a pair of chelae, UN-DG-CR-042 to UNDG-CR-044. Tubará Formation, Upper Miocene - Pliocene.

Measurements. UN-DG-CR-042, left propodus length = 24.6 mm, height = 9.8 mm; UN-DGCR-043, right dactylus length = 13.8 mm, width = 7.8 mm; UN-DG-CR-044, pair of chelae, right propodus length = 42.1 mm, height = 24.3 mm, right dactylus length = 18.9 mm, height = 9.7 mm, left propodus length = 45.2 mm, height = 12.6 mm, dactylus length = 25.7 mm, height = 11.2 mm.

Comments. Shape of chelae and strong tubercles ornamentation indicates affinity of the study specimens with Petrochirus bouvieri, reported also from the Miocene of Panama (Gatun and Chagres formations) (^{Rathbun, 1919}; ^{Todd and Collins, 2005}).

Infraorder Brachyura Latreille, 1802

Family Aethroidea ^{Dana, 1851}

Genus Hepatus Latreille, 1802

Hepatus lineatinus Collins and Todd in Todd and

Collins, 2005

Figure 3.20 - 3.24

Description. Carapace of medium size, transversely subovate, one-third wider than long, multiple short spines on anterolateral margin, about two-thirds the maximum carapace length, posterolateral margin covered by small granules, about half the maximum length, dorsal carapace regions weakly defined, surface covered by fine granules; sternum narrow, last sternites become much narrower; pleon triangular, narrow, fused somites 3 to 5. Right cheliped robust.

Material. Three nearly complete carapaces, one (UN-DG-CR-045) preserving sternum and abdomen and one other preserving right cheliped, UN-DG-CR-045 to UN-DG-CR-047. Tubará Formation, Upper Miocene-Pliocene.

Measurements. UN-DG-CR-045, carapace with sternum and abdomen, length = 32.1 mm, width = 22.5 mm; UN-DG-CR-046, carapace, length = 18.8 mm, width = 32.4 mm; UN-DGCR-047, carapace with right cheliped, length = 19.4 mm, width = 25.4 mm.

Comments. Size of carapace, cuticle ornamented with fine granules and multiple short spines on anterolateral margins indicate affinity with Hepatus lineatinus. This species is reported from the Miocene and Pliocene of Panama (Gatun and Escudo de Veraguas formations) (^{Todd and Collins, 2005}).

Superfamily Hexapodoidea, ^{Miers, 1886}

Family Hexapodidae ^{Miers, 1886}

Genus Palaeopinnixa^{Vía-Boada, 1966}

Palaeopinixa perornata^{Collins and Morris, 1976}

Figure 4.1

Description. Carapace small, suboval, twice as wide as long; anterior margin two-thirds of maximum width; anterolateral margin concave, twothirds of carapace length; posterolateral margin also concave, one-third the carapace length; posterior margin straight, three-fourths the carapace width; cervical groove deeply impressed; remains of finely granulated cuticle are observed on the steinkern of one specimen; protogastric region distinct; cardiac region with two small tubercles; two small swellings on each side of cardiac region; strong chelipeds with inflated palms, pereiopods 2 to 4 slender.

Material. Two dorsal carapaces and pereiopods found in calcareous concretions UN-DG-CR-64 and UN-DG-CR-65. Las Perdices Formation, Lower Miocene.

Measurements. UN-DG-CR-64, carapace with articulated pereiopods, length = 7.5 mm, width = 11.2 mm; UN-DG-CR-65, carapace with articulated pereiopods, length = 7.2 mm, width = 9.5 mm.

Comments. The small carapace and traces of finely granular cuticle indicate affinity of the Colombian specimens to Palaeopinixa perornata. This species is reported from the early Miocene of Barbados and Trinidad (^{Collins and Morris, 1976}), Venezuela (^{Feldmann and Schweitzer, 2004}; ^{Aguilera et al., 2010}) and Mexico (^{Vega et al., 2009}).

Superfamily Leucosioidea ^{Samouelle, 1819}

Family Leucosiidae ^{Samouelle, 1819}

Subfamily Philyrinae ^{Leach, 1817}

Genus Persephona^{Leach, 1817}

Persephona enigmatica Collins and Todd in Todd

and Collins, 2005

Figure 4.2 - 4.6

Description. Carapace small, subglobose, posterior portion narrow, with three short posterolateral spines; surface finely granular, ornamented by relatively coarse granules, evenly spaced. Orbits suboval.

Material. One complete and one partial carapaces, UN-DG-CR-048 and UN-DG-CR-049. Tubará Formation, Upper Miocene-Pliocene.

Measurements. UN-DG-CR-048, carapace length = 22.1 mm, width = 18.5 mm; UN-DGCR-049, carapace, length = 8.9 mm, width = 12.5 mm.

Comments. The finely granulated cuticle and position, carapace shape and position of the central and two posterolateral spines suggest affinity with this species, also reported from the Pliocene Cayo Agua Formation of Panama (^{Todd and Collins, 2005}).

Superfamily Majoidea ^{Samouelle, 1819}

Family Majidae ^{Samouelle, 1819}

Subfamily Mithracinae ^{MacLeay, 1838}

Genus Microphrys H. ^{Milne-Edwards, 1851}

Microphrys sp.

Figure 4.7

Description. Carapace large, broadly pyriform, somewhat depressed, dorsal surface covered by broadly spaced sharp spines, a small marginal spine or tubercle at lateral angle of branchial region.

Material. One incomplete carapace, UNDG-CR-050. Tubará Formation, Upper Miocene-Pliocene.

Measurements. UN-DG-CR-050, carapace length = 45.7 mm, width = 38.8 mm.

Comments. Carapace subpyriform and dorsal carapace ornament of scattered strong spines, suggest affinity to Microphrys. The sole specimen represents the first fossil record for the genus, however more complete specimens are needed in order to offer a detailed specific identification.

Superfamily Portunoidea ^{Rafinesque, 1815}

Family Portunidae ^{Rafinesque, 1815}

Subfamily Necronectinae ^{Glaessner, 1928}

Genus Necronectes A. ^{Milne-Edwards, 1881}

Necronectes proavitus (Rathbun, 1918)

Figure 4.8 - 4.11

Description. Carapace medium to large, wider than long, dorsal surface weakly convex transversely, covered by fine granules; carapace regions very weakly developed; frontal margin with four short triangular spines; anterolateral margin convex, longer than posterolateral margin, with eight to nine acute triangular spines; posterolateral margin weakly concave; posterior margin one-fourth the maximum carapace width; thoracic sternites narrow, sternites three and four fused, fourth sternites triangular; lateral sternal process well defined, strongly concave and curving around anterolateral angle of fifth somite, two straight marginal faces distally; fifth sternites separated from anterior sternal plate by distinct groove; abdomen triangular, wider at level of fused somites 3 - 5, proximal abdominal somites reduced, carried in subvertical position; buccal cavity rectangular, wider than long; third maxillipeds do not cover axial portion of cavity; no pereiopods or chelipeds preserved.

Material. Five incomplete carapaces, UN-DGCR-052 to UN-DG-CR-056. Tubará Formation, Upper Miocene-Pliocene.

Measurements. UN-DG-CR-052, carapace length = 33.3 mm, width = 54.2 mm; UN-DGCR-053, carapace length = 43.3 mm, width = 62.3 mm; UN-DG-CR-054, carapace length = 23.3 mm, width = 32.3 mm; UN-DG-CR-055, carapace length = 24.1 mm, width = 34.8 mm; UN-DG-CR-056, carapace length = 12.5 mm, width = 22.7 mm.

Comments. Shape and size of carapace, anterolateral margin convex, longer than posterolateral margin, with eight to nine acute triangular spines, are features observed in the new specimens from Colombia that suggest affinity with this species, previously reported from the Miocene of Puerto Rico, Panamá, Venezuela and Ecuador (^{Roberts, 1975}; ^{Schweitzer et al., 2006}; ^{Collins et al., 2009}; ^{Cáceres et al., 2016}).

Genus Scylla De Haan, ¹⁸³³

Scylla sp.

Figure 4.12, 4.13

Description. Carapace wider than long, regions poorly defined, carapace covered by fine granules; anterolateral margins curved, with at least seven spines; female abdominal somites 3 - 5 fused, wide.

Material. One incomplete carapace, UNDG-CR-051. Tubará Formation, Upper Miocene-Pliocene.

Measurements. UN-DG-CR-051, carapace length = 38.5 mm, width = 28.5 mm.

Comments. The single specimen resembles Scylla costata^{Rathbun, 1919}, from the Oligocene - Miocene of Puerto Rico and Haiti, in shape and number of spines on anterolateral margin, but more complete specimens are to be found in order to confirm this affinity.

Subfamily Podophthalminae ^{Dana, 1851}

Genus Euphylax^{Stimpson, 1860}

Euphylax maculatus Collins and ^{Todd in Todd and Collins, 2005}

Figure 4.14 - 4.19

Description. Carapace transversely subovate, length about two-thirds the maximum width, slightly arched transversely, in longitudinal section it rises to rounded protogastric region; cardiac and branchial regions elevated; orbitofrontal margin equals entire carapace width; rostrum wide, T-shaped and deeply constricted at its base; granulated upper orbital margins; anterolateral margins straight, shorter than sinuous posterolateral margins, with four anterolateral short spines; epibranchial ridge distally bounded by double row of granules; hepatic, mesogastric and lateral parts of the metabranchial lobes are depressed, other lobes weakly tumid; thoracic sternite 3 subhexagonal, weakly concave anteromedially; sternite 4 subtrapezoidal, 3 reminder sternites peltoid, becoming narrow towards posterior portion of carapace; male abdomen triangular, wider at level of fused abdominal somites 3 - 5, proximal abdominal somites reduced; female abdomen semicircular, widest at level of somite 3; chelae of similar size and shape, fingers flattened, tricuspidate, dactylus ridged medially, fixed finger ridged along basal margin; dorsal margin of left palm, covered by granules, arranged in longitudinal rows on lateral margins; left palm with three longitudinal keels on outer surface, strong tubercle near junction with carpus.

Material. One complete and four incomplete carapaces UN-DG-CR-057 to UN-DG-CR-061, Tubará Formation, Upper Miocene-Pliocene.

Measurements. UN-DG-CR-057, carapace length = 29.3 mm, width = 46.1 mm; UN-DGCR-058, carapace length = 41.8 mm, width = 66.5 mm; UN-DG-CR-059, carapace length = 20.3 mm, width = 41.4 mm; UN-DG-CR-060, carapace length = 20.1 mm, width = 25.1 mm; UN-DG-CR-061, carapace length = 32.3 mm, width = 38.9 mm.

Comments. Subhexagonal carapace shape, presence of four anterolateral spines and shape and ornamentation of chelae suggest affinity of the Colombian specimens to this species. The species is reported from the Miocene-Pliocene of Panamá and the Pleistocene of Costa Rica (^{Todd and Collins, 2005}).

Superfamily Xanthoidea ^{MacLeay, 1838}

Family Panopeidae ^{Ortmann, 1893}

Subfamily Panopeinae ^{Ortmann, 1893}

Genus Eurytium^{Stimpson, 1859}

Eurytium sp.

Figure 4.20

Description. Carapace of medium size, subhexagonal, wider than long, widest at midlength; cuticle with granules of uniform size; anterior margin two-thirds maximum width, orbits semicircular, small, rimmed, front subrectangular, projected beyond orbits, with median groove; anterolateral margin concave, half the length of carapace; posterolateral margin slightly concave, half the length of carapace; posterior margin straight, narrow, one-third carapace width; protogastric region inverted-subtriangular; mesogastric region subpentagonal, with a narrow process that extends only to base of rostrum; urogatric region depressed, narrow; cardiac region subtrapezoidal; mesobranchial region semioval, inclined; metabranchial region a raised platform; cervical groove deeply impressed.

Material. One incomplete carapace UNDG-CR-063, Tubará Formation, Upper Miocene-Pliocene.

Measurements. UN-DG-CR-063, carapace length = 19.2 mm, width = 17.9 mm. Comments. The specimen resembles Eurytium granulosum^{Schweitzer, Velez-Juarbe, Martinez, Hull, Feldmann, and Santos, 2008}, from the Miocene of Puerto Rico, in size, shape and ornament of carapace, but more complete specimens are needed to confirm this affinity.

4. Conclusions

The new crustacean assemblage from the Neogene of the Caribbean of Colombia represents an important addition to the fossil decapod diversity of Colombia. The shallow marine to estuarine crustacean assemblage reinforces recent interpretations of shallow facies for the Las Perdices and Tubará formations, previously interpreted as composed by deep marine sediments. Due to the numerous reports on fossil decapods from the Caribbean, it is possible to document a strong paleobiogeographic affinity with Neogene (Miocene-Pliocene) crustacean assemblages from Panama, Puerto Rico and Costa Rica.