Pachycheles coelhoi, Ferreira & Tavares, 2019

Ferreira, Luciane Augusto De Azevedo & Tavares, Marcos, 2019, A review of the records of Pachycheles rugimanus A. Milne-Edwards, 1880 (Crustacea: Decapoda: Anomura: Porcellanidae) from Brazil, with the description of a new species, Zootaxa 4568 (1), pp. 185-193: 186-192

publication ID

https://doi.org/10.11646/zootaxa.4568.1.12

publication LSID

lsid:zoobank.org:pub:477F7813-C847-4CAF-B6CD-66B210A68C3C

DOI

http://doi.org/10.5281/zenodo.3510338

persistent identifier

http://treatment.plazi.org/id/020587A7-FFD8-FFB5-41C7-FDEDFBE4FE70

treatment provided by

Plazi

scientific name

Pachycheles coelhoi
status

sp. nov.

Pachycheles coelhoi   sp. nov.

( Figs. 1 View FIGURE 1 A–K, 2A–C, 4A,B)

Pachycheles rugimanus   . — Coelho 1964: 255; Veloso & Melo 1993: 173, 178 (in part); Melo 1999: 227, 242, figs. 163, 164; Coelho et al. 2007: 1, tab 4; Ferreira & Melo 2016: 183 View Cited Treatment . [Not Pachycheles rugimanus A. Milne-Edwards, 1880   ].

Type material. Holotype: male cl 6.4 mm, cw 5.9 mm ( MOUFPE 7491 View Materials ), Brazil, Amapá, Cabo Orange, Project Geomar III, R/V "Almirante Saldanha", Stn 208, 04°52'N: 50°31'30"W, 1971, 118 m. GoogleMaps   Paratype: female cl 4.7 mm, cw 4.4 mm ( MZUSP 39043 View Materials ), same data as holotype GoogleMaps   .

Comparative material. Pachycheles ackleianus A. Milne-Edwards, 1880: 2   males, cl 3.6 mm, cw 4.2 mm and cl 3.1 mm, cw 3.8 mm ( MZUSP 12892 View Materials , ex- MOUFPE 3082 View Materials ), Brazil, Paraíba, Projeto Algas, Stn 86A, 6°36'S– 34°47'W, 26 m. GoogleMaps  

Pachycheles rugimanus A. Milne-Edwards, 1880: 3   males, largest cl 8.1 mm, cw 7.8 mm; smallest cl 7.3 mm, cw 7.1 mm; 1 ovigerous female, cl 7.9 mm, cw 8.4 mm ( USNM 188445 View Materials ), United States, South Carolina, R/ V Dolphin, Stn MARMAP 791041, 32°50'06"N– 78°36'18"W, 21 September 1979, 35 m. 2 males GoogleMaps   , cl 6.2 mm, cw 5.9 mm and cl 5.8, cw 5.6 mm, 2 ovigerous females, cl 7.1 mm, cw 7.2 mm and cl 7.2 mm, cw 7.4 mm ( USNM 150684 View Materials ), Georgia, Sapelo Island , off Sea Buoy, Stn 373, 30°40'43"N– 80°06'07"W, M. Gray coll., 12 September 1963, 50– 59 m. GoogleMaps  

Pachycheles velerae Haig, 1960: 1   male, cl 5.4 mm, cw 4.9 mm ( USNM 110551 View Materials ), Costa Rica, Cocos Island , Chatham Bay, 5°35'50"N– 86°58'55"W, Allan Hancock Expedition, R / V Velero, 14 January 1938, 73– 86 m. GoogleMaps  

Distribution. Currently known only from Cabo Orange, Amapá ( Brazil).

Description. Carapace subcircular, longer than broad in both males and females, quite rugose dorsally, with scattered flattened tubercles dorsally. Frontal region prominent, rugose, slightly depressed on midline. Frontal width less than half of maximum carapace width. Frontal margin distinctly granulate, trilobate in dorsal and frontal views, devoid of setae; median lobe prominent, rounded, overreaching lateral lobes; lateral lobes broad, rounded. Outer orbital angle terminating in well-developed, long teeth. Orbit with rugose margin. Carapace lateral margin well-defined, wrinkled. Epibranchial region slightly swollen. Cervical groove well defined, ending in distinct notch anteriorly. Posterior branchial region with long, transverse rugae; posterolateral margin gently rounded, devoid of setae. Branchiostegite distinctly rugose, not pubescent, divided into calcified plates of different sizes; anterior plate distinctly larger than posterior; sometimes with several much smaller plates posteriorly.

Thoracic sternite 3 trilobate; median lobe broad, rounded, unarmed, not overreaching lateral lobes; lateral lobes narrow, subtriangular. Sternites 4–7 broad, sutures between sternites incomplete, distinct only laterally. Sternite 8 anterior margin slightly convex, posterior margin concave.

Ocular peduncle short; cornea large, rounded, dilated.

Antennular basal segment large, with 2 small distomesial spines. Segments 2–3 unarmed, subcylindrical; segment 3 broadened distally.

Antennal peduncular segments slightly rugose, short. Segment 1 subtriangular, membranous dorsally, calcified ventrally. Segments 2–3 about 2/3 length of segment 3, with well-developed distomesial tubercle. Segment 4 mesial surface with 2 or 3 well-developed granules. Segment 5 about half length of segment 4.

Mxp3 rugose on external surface. Exopod reniform, reaching about half of total length of merus; flagellum well developed. Ischium lateral lobe distinct, well-developed, separated by deep V-shaped incision. Merus as long as ischium; mesial lobe broad, tip rounded, with serrate margin.

P1 similar between male and female; right and left sides unequal in size but similar in armature, robust, eroded, distinctly granulate dorsally; ventral surface with flattened tubercles. Merus about 1/3 length of carpus; mesial lobe subtriangular, well-developed, granulate; 2–4 distal spines well-developed ventrally. Carpus as long as palm; mesial margin with 3–4 granulate, strongly projecting teeth, progressively decreasing in size distally. Dorsal surface of carpus and propodus with 3 pronounced, longitudinal carinae and series of transverse, discrete ridges between the longitudinal carinae. Palm with large, granular tubercle near base of pollex. Fixed finger about 1/3 length of propodus. Dactylus about 2/3 length of propodus. Cutting edges of fingers furrowed, granulate, devoid of setae. Tip of fingers curved, closing tightly.

Walking legs decreasing in size from P2–4, robust, rugose, fringed with dense, short setae on margins, especially on carpi and propodi, and with scattered long setae. Carpi about 2/3 length of P2–4 meri, lateral surface with 2 low, longitudinal, parallel carinae dorsally; dorsal margin with 1 to 3 discrete, dorsodistal spines. Propodi as long as meri, each with 4 spines on ventral surface: 2 spines along ventral margin, 2 on distoventral margin near articulation with dactylus. Dactyli about half length of propodi, each with row of 4 well-developed spines ventrally.

P5 short, ischium 1/4 of length of merus; merus slightly longer than carpus; propodus about 1/3 of length of carpus; dactylus about 1/3 of length of propodus.

Male and female pleon subrectangular, surface of each somite smooth dorsally, lateral margins with short, plumose setae. Male gonopods well developed on somite 2. Female pleopods well developed on somites 3–5. Uropods broad, reaching to distal margin of telson. Telson broader than long, subdivided into 5 plates, nearly smooth on external surface.

Etymology. The new species is named in honour of the late Prof. Petrônio Alves Coelho (Universidade Federal de Pernambuco) in recognition of his outstanding contributions to the taxonomy of the decapod crustaceans in Brazil.

Remarks. Pachycheles coelhoi   sp. nov. superficially resembles P. rugimanus   ( Figs. 2 View FIGURE 2 D–F, 4C, D) and P. velerae   ( Figs. 3 View FIGURE 3 D–F, 4E, F). However, the new species can be separated from both, P. rugimanus   and P. velerae   , in that: (1) the major and minor P1 fingers are similar in shape; the fingers have nearly straight cutting edges and are interlocked subdistally, with the dactyli closing tightly against the fixed fingers, Figs. 1G, H View FIGURE 1 , 2C View FIGURE 2 , 4A, B View FIGURE 4 (in the other two species, the major and minor P1 fingers are unequal in shape; the major P1 fingers leave a broad hiatus when closed and are not interlocked distally, with the dactylus strongly curved to ventral side, Figs. 2F View FIGURE 2 , 3F View FIGURE 3 , 4 View FIGURE 4 C-F); (2) the dorsal surface of the major P1 finger is heavily tuberculated rather than nearly smooth in P. rugimanus   and P. velerae   ( Figs. 2F View FIGURE 2 , 3F View FIGURE 3 , 4C, E View FIGURE 4 ).

Pachycheles coelhoi   sp. nov. is further differentiated from P. rugimanus   by: (1) the carapace front being slightly deflexed and markedly trilobate in dorsal view; the median lobe being strongly projected, distinctly overreaching the tip of cornea in dorsal view and separated from the lateral lobes by broad concave margins ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 ) (versus carapace front markedly deflexed, scarcely trilobate; the median lobe is very low, poorly projected, barely overreaching the tip of cornea and separated from the lateral lobes by nearly straight margins in P. rugimanus   , Fig. 2D View FIGURE 2 ); (2) the median lobe of the thoracic sternite 3 is rounded and separated from the lateral lobes by shallow, gently concave margins ( Figs. 1K View FIGURE 1 , 2B View FIGURE 2 ) rather than distinctly subtriangular and separated from the lateral lobes by straight, laterally V-shaped margins in P. rugimanus   ( Fig. 2E View FIGURE 2 ).

In addition to the above mentioned distinctions, P. coelhoi   sp. nov. differs from P. velerae   in that: (1) the frontal, protogastric and hepatic regions of the carapace are strongly striated transversally, and the epibranchial region is coarsely squamose ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 ) (in P. velerae   the frontal, protogastric and hepatic regions are nearly smooth and the epibranchial region have few minute squamae ( Fig. 3D View FIGURE 3 ); (2) the major P1 fingers cutting surfaces are markedly hollowed along the longitudinal line, with incisor teeth along hollows, and the dactylus cutting edge has no molar tooth ( Figs. 1H View FIGURE 1 , 2C View FIGURE 2 , 4A, B View FIGURE 4 ), whereas in P. velerae   the dactylus and fixed finger are hollowed out only along the distal half and only slightly hollowed distally, respectively. The dactylus and fixed finger each have two longitudinal, subparallel rows of molariform flat teeth along the hollow axes and the dactylus has one strong molar tooth subproximally (considered an autapomorphy of P. velerae   by Harvey 1998) ( Figs. 3F View FIGURE 3 , 4E, F View FIGURE 4 ); (3) the major P1 propodus dorsal surface has a wide, high, heavily tuberculated, elongated upper bulge ( Fig. 4A View FIGURE 4 ), versus a narrow, low, rather smooth, elongated upper ridge in P. velerae   ( Fig. 4E View FIGURE 4 ); (4) the major P1 propodus dorsal surface has an elongated, large, high, heavily tuberculated axial bulge and is provided with discrete, transverse ridges between its upper margin and the upper bulge ( Fig. 4A View FIGURE 4 ), whereas in P. velerae   , the axial bulge is rounded, far smaller and lower ( Fig. 4E View FIGURE 4 ) and there is a net of ridges of different sizes forming a reticulated, wrinkled pattern instead of transverse ridges ( Fig. 4E View FIGURE 4 ). The more elongate carapace and projecting front, the sparse setation on the chelipeds and carapace, and the dense plumose setae on pereopods 2–4 were also regarded as additional autapomorphies of P. velerae   by Harvey (1998), but these characters are shared with P. coelhoi   sp. nov.

In the past, Pachycheles coelhoi   sp. nov. has been confused with P. ackleianus   ( Fig. 3 View FIGURE 3 A–C). The two species are somewhat similar, but can be easily separated in that: (1) the carapace is longer than broad in males and females ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 ), whereas in P. ackleianus   , it is distinctly broader than long in males and females ( Fig. 3A View FIGURE 3 ); (2) the front is slightly deflexed and distinctly trilobate in dorsal view ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 ), versus distinctly deflexed and nearly straight in dorsal view in P. ackleianus   ( Fig. 3A View FIGURE 3 ); (3) the P1 carpus and propodus are distinctly granulate and the carpus has 3 pronounced, longitudinal carinae and a series of transverse, discrete ridges between the longitudinal carinae ( Figs. 1G, H View FIGURE 1 , 2C View FIGURE 2 , 4A, B View FIGURE 4 ), whereas in P. ackleianus   , the carpus and propodus are covered with flattened tubercles grouped together in longitudinal rows ( Fig. 3C View FIGURE 3 ); and (4) the male gonopods are present on somite 2 versus absent in P. ackleianus   .

Haig (1960) and Harvey (1998) put forward a number of distinguishing characters between P. velerae   and P. rugimanus   . Additional characters differentiating P. velerae   from P. rugimanus   include the poorly defined carapace regions ( Fig. 3D View FIGURE 3 ), compared to well defined in P. rugimanus   , especially the protogastric and epibranchial regions ( Fig. 2D View FIGURE 2 ), and the anteriorly trilobate thoracic sternite 3 with the median lobe rounded and separated from the lateral lobes by shallow, gently concave margins ( Fig. 3E View FIGURE 3 ), whereas in P. rugimanus   , the median lobe is distinctly subtriangular and separated from the lateral lobes by straight, laterally V-shaped margins ( Fig. 2E View FIGURE 2 ).

Harvey (1998) considered that P. velerae   and P. rugimanus   are sister taxa on opposite sides of the Isthmus of Panama based on an unpublished phylogenetic analysis of Pachycheles   and Neopisosoma   . Future phylogenetic analysis might well reveal that P. velerae   is actually sister to P. coelhoi   sp. nov.

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Porcellanidae

Genus

Pachycheles

Loc

Pachycheles coelhoi

Ferreira, Luciane Augusto De Azevedo & Tavares, Marcos 2019
2019
Loc

Pachycheles rugimanus

Ferreira, L. A. A. & Melo, G. A. S. 2016: 183
Coelho, P. A. & Almeida, O. A. & Bezerra, L. E. A. & Souza-Filho, J. F. 2007: 1
Melo, G. A. S. 1999: 227
Veloso, V. G. & Melo, G. A. S. 1993: 173
1993
Loc

Pachycheles velerae

Haig, J. 1960: 1
1960
Loc

Pachycheles rugimanus

Milne-Edwards, A. 1880: 3
1880