Boreas uglowi, Cumberlidge & Sternberg, 2002

Cumberlidge, Neil & Sternberg, Richard V., 2002, The freshwater crabs of Madagascar (Crustacea, Decapoda, Potamoidea), Zoosystema 24 (1), pp. 41-79 : 75-77

Boreas uglowi n. sp.

( Fig 2D ; 3G ; 4L ; 5H ; 6L ; 7Q, R ; 8E ; 10A, B ; 11L )

Madagapotamon ankaraharae – Bott 1965 (part): 347, 348, fig. 9d, e, pl. 5, figs 23-25 (non fig. 9a-c).

MATERIAL EXAMINED. — Madagascar. Nosy-Bé, Madagascar, 1 ad., holotype cw 29.3, cl 21.3, ch 10, fw 8.5 mm ( MNHN-B 12292). — Diego-Suarez (now Antsiranana), coll. J. Millot, 1 ad. cw 24.3, cl 18.8, ch 8.6, fw 7.6 mm ( MNHN-B 5028). — Nosy-Bé, Autumn 1927, coll. J. Millot, 1 ad., cw 19.8 mm, broken in pieces ( MNHN-B 5029). — Nosy-Bé, X.1922, coll. J. Millot, 1 ad. cw 25 mm, carapace damaged ( MNHN-B 26147). — Nosy Komba, 500 m altitude, on a path, XII.1922, coll. J. Millot, 1 subadult cw 22, cl 16, ch 8, fw 6.5 mm, 1, broken cw 28.5, cl 19.5 mm, 1 juv. cw 18, cl 13.5, ch 6, fw 5 mm ( MNHN-B 12293).

TYPELOCALITY. — Nosy-Bé, Madagascar.

ETYMOLOGY. — The species is named for Dr. Roger Frederick Uglow, Department of Applied Biology, University of Hull, U.K., in recognition of his prolific contributions to decapod crustacean physiology.

DISTRIBUTION. — Madagascar, Nosy-Bé ( Fig. 11L ).

DIAGNOSIS. — As for genus.

DESCRIPTION

Carapace outline transversely oval (wider than long, cw/fw = 3.2, cl/fw = 2.3), moderately arched (ch/fw = 1.1); epigastric, postorbital crests faint, not fused; postorbital crests not meeting anterolateral margins; exorbital, epibranchial teeth similar, both low, blunt, continuous with anterolateral margin; anterior regions of carapace surface smooth; anterolateral, posterolateral regions with short carinae; semi-circular, urogastric grooves deep; cervical grooves very short. Suborbital margin raised, faintly granulated. Front highly deflexed; frontal margin smooth, straight; frontal, posterior margins of carapace wide (cw 0.3 mm). Suborbital, subhepatic, regions of carapace sidewall smooth or with faint granules; pterygostomial region smooth with sparse short setae or a few small granules near third maxilliped. Carapace sidewall in three parts; distinct vertical sulcus on sidewall running from epibranchial tooth to longitudinal (epimeral) groove, dividing suborbital, hepatic regions.

Mandibular palp two-segmented, terminal segment with flat basal thickening at junction between segments; ischium of third maxilliped smooth, vertical sulcus either faint or completely absent; exopod of third maxilliped medium length, reaching only proximal part of merus, exopod with long flagellum. Thoracic sternal sulcus s1/s2 not visible; sternal sulcus s2/s3 deep, horizontal; sternal sulcus s3/s4 reduced to two short side notches; anterior sternum smooth; episternal sulci s4/e4, s5/e5, s6/e6, s7/e7 smooth, no groove visible. Male abdomen slim, triangular.

Gonopod 1 terminal article straight, slim, short (ratio length terminal article to subterminal segment 0.25), tip directed weakly outward, longitudinal groove clearly visible on ventral, superior sides, not visible on dorsal side; terminal article/ subterminal segment junction distinct, with narrow dorsal membrane; lateral, medial folds of ventral side of terminal article equal in height, width. Gonopod 2 longer than gonopod 1; gonopod 2 terminal article medium flagellum, ratio length gonopod 2 terminal article to subterminal segment 0.6.

Dactylus of right, left chelipeds relatively narrow (one-quarter height of palm), upper margin smooth, finger of dactylus curved; slim interspace between closed fingers; finger of propodus onethird height of palm lower margin of propodus of cheliped slightly indented. Dactylus with series of small teeth interspersed by larger teeth; finger of propodus of right cheliped with large fused molar tooth. Anterior, posterior inferior margins of ischium of p1 smooth. Inferior margins of merus faintly granulated, distal margin with single low distal meral tooth; superior margin of merus with row of granules. First carpal tooth of carpus of cheliped large, wide, with pointed tip; second carpal tooth small. With pointed tip, followed by small granules. Anterior, posterior margins of propodi of p5 slightly serrated. Walking legs (p2- p5) normal length, neither elongated nor shortened, ratio length merus p5 to cw 0.3. P5 propodus short, broad, margins serrated; dactylus of p5 short, half length of dactylus of p2-p4.

REMARKS

The generic assignment and validity of Potamon (Geothelphusa) ankaraharae remains uncertain. Nobili’s (1906) type is unavailable and the figures of the type in Bott (1965: fig. 9a-c) do not show the mandible or first gonopod. It should be noted that the male specimen cw 28 mm (MNHN Paris, no number provided) labeled M. ankaraharae in Bott (1965: fig. 9d, e, pl. 5 figs 23-25) from Diego-Suarez (now Antsiranana) was not part of the type series from Ankarahara, and probably does not represent this taxon. We consider it likely that this specimen was misidentified, and that it may not actually belong to the same species as P. (G.) ankaraharae sensu Nobili, 1906 . Although Bott (1965) did not provide a catalogue number, it is likely that the specimen from Diego-Suarez (MNHN-B 28) is the same one that was used (in part) in the redescription of M. ankaraharae by Bott (1965: pl. V, figs 23-25, fig. 9e, f). For this reason, the illustrations of gonopods 1 and 2 in Bott 1965 (fig. 9d, e), the photographs of the whole animal (pl. V, figs 23- 25), and the text description of the mandibular palp as simple, may describe these structures in B. uglowi n. gen, n. sp., rather than P. (G.) ankaraharae sensu Nobili, 1906 . This means that the gonopods and mandible of P. (G.) ankaraharae sensu Nobili, 1906 , still await description.

Characters of the carapace, thoracic sternum and walking legs of B. uglowi n. gen, n. sp. are similar to those shown in the figures of the type of P. (G.) ankaraharae provided by Bott (1965). The two taxa have a similar carapace outline and texture and walking legs of similar proportions. The two taxa can be distinguished by examination of the ischium of the third maxilliped, which has a deep vertical groove in P. (G.) ankaraharae , but which is characteristically faint or lacking in B. uglowi n. gen, n. sp. The specimens from northern Madagascar from Diego-Suarez (MNHN-B 5028), Nosy-Bé (MNHN-B 5029) and (MNHN-B 26147), and Nosy Komba (MNHN-B 12293) that were formerly identified as P. (G.) ankaraharae are included here in the new taxon, because they resemble B. uglowi n. gen, n. sp. very closely. These specimens differ from B. uglowi n. gen, n. sp. in the texture of the pterygostomial region of the carapace sidewall, which is smooth in B. uglowi n. gen, n. sp. and distinctly setose in these other specimens.

Figures

FIG. 2. — Dorsal view of the carapace of adult males of Madagascan freshwater crabs (A-C based on Ng & Takeda 1994); A, Skeleosophusa gollhardi (Bott, 1965), holotype (MNHN B-5165); B, S. prolixa Ng & Takeda, 1994, holotype, (MRSN); C, S. eumeces Ng & Takeda, 1994, holotype, (MRSN); D, Boreas uglowi n. gen., n. sp., holotype (MNHN B- 11292); E, Madagapotamon humberti Bott, 1965; F, Marojejy longimerus Cumberlidge, Boyko & Harvey, 2002, holotype, (AMNH 17833). Scale bar: A, 7.2 mm; B, 7.1 mm; C, 6.5 mm; D, 9 mm; E, 9.4 mm; F, 6 mm.

FIG. 3. — Inferior view of the sternum of adult males of Madagascan freshwater crabs; A, Hydrothelphusa agilis A. Milne-Edwards, 1872; B, H. madagascariensis (A. Milne-Edwards, 1872); C, H. bombetokensis (Rathbun, 1904); D, H. goudoti (H. Milne Edwards, 1853) n. comb.; E, Malagasya antongilensis (Rathbun, 1905) n. comb.; F, M. goodmani (Cumberlidge, Boyko & Harvey, 2002) n. comb., G, Madagapotamon humberti Bott, 1965; H, Marojejy longimerus Cumberlidge, Boyko & Harvey, 2002; I, Boreas uglowi n. gen., n. sp. Scale bar: A, 11.7 mm; B, 17.2 mm; C, 15.9 mm; D, 14.5 mm; E, 10.2 mm; F, 7 mm; G, 9.6 mm; H, 6.4 mm; I, 9.1 mm.

FIG. 4. — Left mandible of Madagascan freshwater crabs, frontal view showing the palp (J, K based on Ng & Takeda 1994); A, Hydrothelphusa agilis A. Milne-Edwards, 1872; B, H. madagascariensis (A. Milne-Edwards, 1872); C, H. bombetokensis (Rathbun, 1904); D, H. goudoti (H. Milne Edwards, 1853) n. comb.; E, Malagasya antongilensis (Rathbun, 1905) n. comb.; F, M. goodmani (Cumberlidge, Boyko & Harvey, 2000) n. comb.; G, Marojejy longimerus Cumberlidge, Boyko & Harvey, 2000; H, Boreas uglowi n. gen., n. sp.; I, Skeleosophusa gollhardi (Bott, 1965); J, S. prolixa Ng & Takeda, 1994; K, S. eumeces Ng & Takeda, 1994; L, Madagapotamon humberti Bott, 1965. Scale bar: A-I, K, L, 1.0 mm; J, 1.25 mm.

FIG. 5. — Left third maxilliped of Madagascan freshwater crabs, frontal view (J, K based on Ng & Takeda 1994); A, Hydrothelphusa agilis A. Milne-Edwards, 1872; B, H. madagascariensis (A. Milne-Edwards, 1872); C, H. bombetokensis (Rathbun, 1904); D, H. goudoti (H. Milne Edwards, 1853) n. comb.; E, Malagasya antongilensis (Rathbun, 1905) n. comb.; F, M. goodmani (Cumberlidge, Boyko & Harvey, 2002) n. comb.; G, Marojejy longimerus Cumberlidge, Boyko & Harvey, 2002; H, Madagapotamon humberti Bott, 1965; I, Skelosophusa gollhardi (Bott, 1965); J, S. prolixa Ng & Takeda, 1994; K, S. eumeces Ng & Takeda, 1994; L, Boreas uglowi n. gen., n. sp. Scale bar: A-D, 5.0 mm; E-L, 3.5 mm.

FIG. 6. — Superior view of the carpus of the cheliped (pereiopod 1) of adult males of Madagascan freshwater crabs (J, K based on Ng & Takeda 1994); A Hydrothelphusa agilis A. Milne-Edwards, 1872; B, H. madagascariensis (A. Milne-Edwards, 1872); C, H. bombetokensis (Rathbun, 1904); D, H. goudoti (H. Milne Edwards, 1853) n. comb.; E, Malagasya antongilensis (Rathbun, 1905) n. comb.; F, M. goodmani (Cumberlidge, Boyko & Harvey, 2002) n. comb.; G, Madagapotamon humberti Bott, 1965; H, Marojejy longimerus Cumberlidge, Boyko & Harvey, 2002; I, Skeleosophusa gollhardi (Bott, 1965); J, S. prolixa Ng & Takeda, 1994; K, S. eumeces Ng & Takeda, 1994; L, Boreas uglowi n. gen., n. sp. Scale bar: A-D, 5.5 mm; E-L, 3.5 mm.

FIG. 7. — Superior and inferior views of the merus of the cheliped (pereiopod 1) of adult males of Madagascan freshwater crabs; A, B, Hydrothelphusa agilis A. Milne-Edwards, 1872; C, D, H. madagascariensis (A. Milne-Edwards, 1872); E, F, H. bombetokensis (Rathbun, 1904); G, H, H. goudoti (H. Milne Edwards, 1853) n. comb.; I, J, Malagasya antongilensis (Rathbun, 1905) n. comb.; K, L, Madagapotamon humberti Bott, 1965; M, N, Skelosophusa gollhardi (Bott, 1965); O, P, Marojejy longimerus Cumberlidge, Boyko & Harvey, 2002; Q, R, Boreas uglowi n. gen., n. sp. Scale bar: A-H, 5.0 mm; I-T, 3.0 mm.

FIG. 8. — Last walking leg (pereiopod 5) of adult males of Madagascan freshwater crabs (H based on Ng & Takeda 1994); A, Hydrothelphusa agilis A. Milne-Edwards, 1872; B, H. madagascariensis (A. Milne-Edwards, 1872); C, H. bombetokensis (Rathbun, 1904); D, H. goudoti (H. Milne Edwards, 1853) n. comb.; E, Boreas uglowi n. gen., n. sp.; F, Marojejy longimerus Cumberlidge, Boyko & Harvey, 2002; G, Madagapotamon humberti Bott, 1965; H, Skelosophusa prolixa Ng & Takeda, 1994; I, Malagasya antongilensis (Rathbun, 1905) n. comb.; J, M. goodmani (Cumberlidge, Boyko & Harvey, 2002) n. comb. Scale bar: A-D, 5.0 mm; E-L, 2.6 mm.

FIG. 10. — Right first gonopod (dorsal and ventral views) of adult males of Madagascan freshwater crabs; A, B, Boreas uglowi n. gen., n. sp.; C, D, Malagasya antongilensis (Rathbun, 1905) n. comb.; E, F, Skeleosophusa gollhardi (Bott, 1965); G, H, Madagapotamon humberti Bott, 1965; I, J, Marojejy longimerus Cumberlidge, Boyko & Harvey, 2002. Scale bar: 4.0 mm.

FIG. 11. — Summaries of the known distribution of the Madagascan freshwater crabs; A, Hydrothelphusa agilis A. Milne-Edwards, 1872; B, H. madagascariensis (A. Milne-Edwards, 1872); C, H. bombetokensis (Rathbun, 1904); D, H. goudoti (H. Milne Edwards, 1853); E, Marojejy longimerus Cumberlidge, Boyko & Harvey, 2002; F, Malagasya antongilensis (Rathbun, 1905) n. comb.; G, M. goodmani (Cumberlidge, Boyko & Harvey, 2002) n. comb.; H, Madagapotamon humberti Bott, 1965; I, Skelosophusa gollhardi (Bott, 1965); J, S. prolixa Ng & Takeda, 1994; K, S. eumeces Ng & Takeda, 1994; L, Boreas uglowi n. gen., n. sp.