Phallangothelphusa tangerina, Campos & Lasso & Arias, 2019

Campos, Martha R., Lasso, Carlos A. & Arias, Maribel, 2019, A new species of freshwater crab of the genus Phallangothelphusa Pretzmann, 1965, from the foothills of the Serranía Yariguíes of Colombia (Crustacea: Decapoda: Pseudothelphusidae), Zootaxa 4550 (4), pp. 579-584 : 580-583

Phallangothelphusa tangerina n. sp.

( Figs. 1 , 2 )

Material examined. Holotype: male (cl 16.1 mm, cb 25.8 mm), IAvH-3212 Colombia, Santander Department, Municipio Carmen de Chucurí, Vereda La Belleza, foothills of the Serranía Yariguíes , La Concordia stream, tributary of Cascajales river , elevation 702 m, 6°34’8.07”N, 73°34’9.38”W, 12 Jun 2018, leg. M. Arias. Paratypes: 1 male (cl 10.1 cm, cb 16.1 mm), 1 female (cl 12.5 mm, cb 21.0 mm), IAvH- 3213, 3214, 5 males (cl 9.1–16.9 mm, cb 15.0– 27.7 mm), 3 females (cl 12.3–16.8 mm, cb 20.7–24.1 mm), ICN-MHN-CR 3383. Same locality data as for holotype .

Additional material examined: Colombia, Santander Department, Municipio Carmen de Chucurí, Vereda La Belleza, foothills of the Serranía Yariguíes , La Danta stream, tributary of Cascajales river , elevation 773 m, 6°34’49.3”N, 73°34’16.7”W, 23 Feb 2018, leg. M. Arias, 1 male (cl 14.9 mm, cb 24.9 mm), 3 females (cl 11.0– 14.5 mm, cb 18.0– 23.8 mm), ICN-MHN-CR 3384 .— Colombia, Santander Department , Municipio Carmen de Chucurí, Vereda La Belleza, foothills of the Serranía Yariguíes, La Leona stream, tributary of Cascajales river , elevation 713 m, Santander Department , Colombia, 6°34’35.7”N, 73°34’30.7”W, 11 Jun 2018, leg. M. Arias. 3 females (cl 14.7–16.3 mm, cb 22.1–29.0 mm), ICN-MHN-CR 3385 .

Diagnosis. Mesial process of first male gonopod formed by rounded projection; lateral process protuberant, of irregular form, wide, rounded basally and decreasing in size distally, inwardly turned, directed mesio-distally, covered by rows of spinules; conspicuous acute spine with a small channel in its base, tip upwards, directed cephalically on cephalo-mesial border of apex; lateral process beyond the cephalo-mesial spine; apex nearly flat distally, in caudal view, outline oval, in distal view, bearing numerous, conspicuous brown spinules. Third maxilliped with exognath 0.8 times length of ischium.

Description of holotype. Carapace ( Fig. 1A ) with straight, wide, deep cervical grooves, becoming indistinct towards margins of carapace; antero-lateral margins with wide deep notch behind outer orbital angle, notch fringed with papillae, with 6 papillae before cervical grooves; lateral margins with approximately 22 papilliform teeth, diminishing in size posteriorly; postfrontal lobes low, oval, delimited anteriorly by transverse depression; median groove shallow; front low, slightly excavated, upper border convex with slight middle depression in dorsal view, marked with row of papillae, lower margin nearly straight in frontal view, conspicuously thickened; upper, lower orbital margins each fringed with tubercles ( Fig. 1B ); dorsal surface of carapace smooth, covered by small papillae, regions demarcated; third maxilliped with shallow depression on subdistal external margin of merus, exognath 0.8 times length of ischium ( Fig. 1E ); orifice of efferent branchial channel open, nearly ovate with slight extension of the lateral lobe of the epistome ( Fig. 1D ).

First pereopods heterochelous ( Fig. 1A ); right cheliped larger than left, merus with 3 crests as follows: upper crest with rows of tubercles of different sizes, internal lower crest with 2 tight rows of large tubercles, diminishing in size proximally, external lower crest with row of papillae; carpus with blunt subdistal spine, follows by 4 rounded tubercles; palms of both chelipeds smooth, palm of larger (right) cheliped strongly swollen, fingers 1.3 length of palm, gaping when closed, tips crossing ( Fig. 1C ); palm of smaller cheliped moderately swollen, fingers 1.4 length of palm, not gaping when closed, tips crossing. Walking legs (second to fifth pereopods) slender ( Fig. 1A ), dactyli each about 1.5 times as long as propodi, with 5 longitudinal rows of large spines diminishing in size proximally, arrangement of spines on dactylus of left second pereopod as follows: anterolateral, anteroventral rows each with 5 spines, external row with 5 spines, postero-ventral, postero-lateral rows each with 4 spines.

First male gonopod straight, wide in caudal view; caudal lobe slightly sinuous, ending in rounded lobe basally, covered by rows of conspicuous setae; prominent ridge basal to beyond mid portion, running parallel to caudal lobe; subdistal lateral side with rounded protuberance, fringed with spinules, middle wide constriction, sinuous from middle to basal portion; mesial side sinuous; mesial process formed by rounded projection; lateral process protuberant, of irregular form, wide, rounded basally and decreasing in size distally, inwardly turned, directed meso-distally, covered by rows of spinules; a conspicuous acute spine with a small channel in its base, tip upwards, directed cephalically on cephalo-mesial border of apex; lateral process beyond the cephalo-mesial spine; apex nearly flat distally, in caudal view, outline oval, in distal view, bearing numerous, conspicuous brown spinules ( Fig. 2 A–E). Second male gonopod slightly sinuous with distal portion rounded, covered by rows of spinules, internal portion concave ( Fig. 2 F, G ).

Color. The unpreserved holotype is orange (near Orange Rufous, 132C) on the dorsal side of the carapace. The chelae are orange (near Spectrum Orange, 17). The walking legs are light yellow (near Chamois, 123D) with marbled markings design (near Cinnamon, 123A) dorsally and ventrally. The ventral surface of the carapace is light yellow with orange spots (near Chamois, 123D and Orange Rufous, 132C). Freshly alcohol-preserved holotype is brown (near Brussels Brown, 121B) with stripes (near Cinnamon Rufous, 40) demarcating the regions, on the dorsal side of the carapace. The walking legs are brown (near Antique Brown, 37) dorsally, and (near Cinnamon, 39) ventrally. The chelae are orange (near Orange Rufous, 132C) dorsally and light brown (near Buff, 124) ventrally. The ventral surface of the carapace is light brown with orange spots (near Cinnamon, 39 and Orange Rufous, 132C).

Habitat. The specimens were collected by hand under stones or in the leaf litter at the margins of a secondary forest stream, at the earth-water interface. The stream was surrounded by a gallery forest and characterized by high-turbidity water, sandy-clay soil and limestone substrate. It is important to mention that P. tangerina n. sp. occurs syntopically with another freshwater crab Hypolobocera bouvieri bouvieri , in underwater microhabitats under rocks in the streambed.

Etymology. The specific epithet refers to the tangerine color of the species in its natural environment.

Remarks. Phallangothelphusa tangerina n. sp. is most similar to P. magdalenensis Campos, 1998 (see Campos 2014: figs. 220A–E). The main distinguishing features between the two species are in the first male gonopod: (1) the mesial process is formed by rounded projection in P. tangerina n. sp. ( Fig. 2A, C, E ), whereas in P. magdalenensis the mesial process is formed by two projections with a small recess between them, with the distal one semicircular and larger than the finger-like proximal projection ( Campos 2014: fig. 220B–E); (2) the lateral process is protuberant, irregular in form, wide, rounded basally and decreasing in size distally, inwardly turned, directed meso-distally, covered by rows of spinules, and equal in length to the mesial process in P. tangerina n. sp. ( Fig. 2 A–E), whereas in P. magdalenensis it is prominent, semicircular, inwardly turned, directed mesially, and shorter than proximal mesial projection of the mesial process ( Campos 2014: fig. 220C–E); (3) the cephalo-mesial border of the apex has a conspicuous acute spine, with a small channel in its base, tip upwards and directed cephalically in P. tangerina n. sp. ( Fig. 2 B–E), whereas in P. magdalenensis this spine has the tip downwards and directed cephalically ( Campos 2014: fig. 220C–E); (4) the apex is nearly flat distally in caudal view, and has an oval outline in distal view in P. tangerina n. sp. ( Fig. 2E ), whereas in P. magdalenensis it shows a rounded slope in caudo-cephalic direction, with a semicircular outline in distal view ( Campos 2014: fig. 220E).

Figures

FIGURE 1. Phallangothelphusa tangerina sp. nov., male holotype (cl 16.1 mm, cb 25.8 mm), IAvH-3212. A, habitus, dorsal view; B, frontal view of carapace; C, chela of large cheliped, external view; D, opening of left efferent branchial channel, external view; E, left third maxilliped, external view.

FIGURE 2. Phallangothelphusa tangerina sp. nov., male holotype, IAvH-3212, left first (A–E) and second (F, G) gonopods. A, left first gonopod, caudal view; B, same, lateral view; C, same, cephalic view; D, same, mesial view; E, apex distal view; F, left second gonopod, caudal view; G, distal part of second gonopod. 1, mesial process; 2, lateral process; 3, meso-cephalic spine; 4, spermatic channel.