Hydrothelphusa agilis A. Milne-Edwards, 1872

Cumberlidge, N., Reed, S. K. & Boyko, C. B., 2004, Distribution patterns of the Malagasy freshwater crabs (Crustacea: Decapoda: Brachyura), Journal of Natural History 38, pp. 1133-1157 : 1135-1141

Hydrothelphusa agilis A. Milne-Edwards, 1872

(figure 2A) Hydrothelphusa agilis A. Milne-Edwards, 1872: 2 (type locality: Madagascar, Sakaleone

River); Rathbun, 1905: 266–268, figure 72, pl. 15, figure 7; Balss, 1929: 357; Pretzmann,

1961: 165; Cumberlidge, 1997: 584–585; Cumberlidge and Boyko, 2001: 126; Cumberlidge and Sternberg, 2002: 48, 50–51, figures 1A, 3A, 4A, 5A, 6A, 7A, B, 8A, 9A–D, 11A,

tables 1 –4. Hydrothelphusa agilis agilis Bott, 1965: 340–341 , figure 4, pl. 2 figures 8, 9, pl. 4, figure 18;

Rabeharisoa, 1996: 156–157.

Material examined. All coll. J.-M. Elouard and colleagues (see Acknowledgements). Madagascar: one male (cw 23.8 mm), Mangoro River , affluent of Tetivato River , basin of Mangoro River , Betafo, 840 m asl, 18°52∞37∞∞S, 48°06∞55∞∞E, 3 April 1992 ( FMNH 5724 ). Four males (cws 18.3, 46.9, 50.6, 56.1 mm), together with H. madagascariensis , affluent of Iantara River , basin of the Manampatrana River , Andringitra, 1370 m asl, 22°13∞23∞∞S, 47°01∞53∞∞E, 16 November 1993 ( FMNH 5728 ). Two males (cws 22.3, 36.1 mm), one adult female (cw 53.6 mm), together with H. madagascariensis, Ambatandrano River, basin of the Namorona River Ambatandrano, 775 m asl, 21°14∞45∞∞S, 47°26∞32∞∞E, 17 April 1994 ( FMNH 5735 ). One juvenile male (cw 13.5 mm), Vakoho River , basin of Sakanila River , Lakato road, 812 m asl, 19°06∞25∞∞S, 48°23∞12∞∞E, 21 March 1995 ( FMNH 5741 ). Two males (cws 19.8, 20 mm) ( FMNH 5743 ). Two males (cws 12.1, 21.5 mm), basin of Rianila River , Lakato road, 1050 m asl, 19°03∞07∞∞S, 48°21∞38∞∞E, 21 March 1995 ( FMNH 5744 ). One juvenile, Makis River , basin of Antongombato River , base camp, 1075 m asl, 12°31∞40∞∞S, 49°10∞09∞∞E, 31 March 1995 ( FMNH 5746 ). One juvenile, Makis River , basin of Antongombato River , Mt Ambre-Aval , 1040 m asl, 12°31∞31∞∞S, 49°10∞22∞∞E, 1 April 1995 ( FMNH 5747 ). Two males (cws 23.2, 39.2 mm), Sahatany River , basin of Rianila River , Périnet-Réserve, Parc National d’Andasibe-Mantadia, 935 m asl, 18°51∞10∞∞S, 48°25∞39∞∞E, 13 April 1995 ( FMNH 5750 ). Three males (cws 14.2, 14.9, 22.8 mm), camp on road to Lakato, 1075 m asl, 19°03∞30∞∞S, 48°21∞50∞∞E, 19 October 1995 ( FMNH 5756 ). Two males (cws 28.1, 35.2 mm), Manambolo River , basin of Ivondro River , Ampasimadinika, 44 m asl, 18°24∞53∞∞S, 49°09∞51∞∞E, 17 January 1996 ( FMNH 5761 ). One male (cw 20.1 mm), Tsaratango River , basin of Namorona River , Tsaratango, 585 m asl, 21°16∞33∞∞S, 47°31∞50∞∞E, 8 November 1996 ( FMNH 5765 ). Four males (cws 14.4, 16.2, 18.6, 19.4 mm), one juvenile (cw <10 mm), basin of Namorona River , Hotel Domaine nature, 21°15∞07∞∞S, 47°26∞36∞∞E, 6 November 1996 ( FMNH 5767 ). One male (cw 41.7 mm), Tsaratango River , basin of Namorona River , 537 m asl, 21°16∞20∞∞S, 47°31∞35∞∞E, 13 November 1996 ( FMNH 5768 ). One male (cw 27.5 mm), Sahatandra River , basin of Rianila River , Ambodirina , 980 m asl, 19°01∞32∞∞S, 48°20∞28∞∞E, 27 November 1996 ( FMNH 5770 ). Three males (cws 17.7, 18.4, 19.7 mm), basin of Rianila River , affluent of Sahatandra River , 1050 m asl, 19°02∞22∞∞S, 48°21∞51∞∞E, 22 April 1997 ( FMNH 5773 ). Two males (cws 15.2, 21.5 mm), basin of Rianila River , Lakato road, 1050 m asl, 19°02∞40∞∞S, 48°21∞48∞∞E, 22 April 1997 ( FMNH 5774 ). One male (32.1 mm), Gri-Gri , Ilazana River , basin of Rianila River , 430 m, 18°58∞54∞∞S, 48°36∞41∞∞E, 24 April 1997 ( FMNH 5775 ). One male (cw 32.2 mm), Beharena River , basin of Betsiboka River , Antaniditra , 1370 m asl, 18°25∞43∞∞S, 48°02∞55∞∞E, 22 November 1997 ( FMNH 5777 ). One male (cw 17.8 mm), basin of Rianila River , affluent of Sahatandra River , Moramanga , 800 m asl, 18°56∞27∞∞S, 48°29∞12∞∞E, 22 April 1998 ( FMNH 5778 ). One juvenile, Sandrakatrana River , basin of Rianila River , Ambodiaviavy , 420 m asl, 18°57∞50∞∞S, 48°38∞50∞∞E, 30 April 1998 ( FMNH 5779 ). One juvenile, Sandrakatrana River, basin

Fig. 3. Summaries of the known distribution of seven species of Malagasy freshwater crabs belonging to the genera Marojejy , Boreas , Malagasya and Skelosophusa . (A) Marojejy longimerus ; (B) B. uglowi ; (C) Malagasya antongilensis (circle), Malagasya goodmani (triangle); (D) S. gollhardi (cross); S. prolixa (×); S. eumeces (circle). (C) Includes all known localities (17 different sites) between latitudes 12° and 24°S for Malagasya antongilensis , all taken from the literature (Cumberlidge, 1997, 1998; Cumberlidge and Sternberg, 2002), and one locality for M. goodmani from Cumberlidge and Sternberg (2002). (D) Includes all known localities for Skelosophusa , all taken from the literature (Ng and Takeda, 1994; Cumberlidge and Sternberg, 2002). Data for Marojejy and Boreas are taken from the present study and from the literature (Cumberlidge and Sternberg, 2002). Black broken lines indicate freshwater ecoregion boundaries, shaded broken lines indicate provincial boundaries, and the shaded area indicates land at, and above, the 800 m contour.

of Rianila River, Ambodaviavy, 325 m asl, 18°57∞45∞∞S, 48°40∞16∞∞E, 30 April 1998 ( FMNH 5780 ) . Two males (cws 18.9, 21.2 mm), one juvenile (cw <10 mm), basin of Rianila River, Périnet-Réserve, Parc National d’Andasibe-Mantadia , 900 m asl, 18°52∞39∞∞S, 48°25∞29∞∞E, 30 May 1998 ( FMNH 5781 ) . One juvenile, 17, 15 km east of Morarano , basin of Rianila River, 980 m asl, 18°40∞32∞∞S, 48°22∞21∞∞E ( FMNH 5782 ) . Three juveniles, Makis River, basin of Antongombato River, northern affluent, 990 m asl, 12°30∞54∞∞S, 49°10∞47∞∞E, 19 March 1999 ( FMNH 5783 ) . One juvenile, camp on road to Lakato, basin of Rianila River, 75 m asl, 19°03∞30∞∞S, 48°21∞50∞∞E, 15 October 1998 ( FMNH 5784 ) . One male (cw 15.6 mm), Lakato road, basin of Rianila River, 1050 m asl, 19°02∞40∞∞S, 48°21∞48∞∞E, 16 October 1998 ( FMNH 5785 ) . Two males (cws 21.4, 26.2 mm), Moramanga, basin of Mangoro River, 940 m asl, 19°05∞57∞∞S, 48°14∞13∞∞E, 23 October 1998 ( FMNH 5787 ) . One male (cw 21.6 mm), Anosibe An’ala, basin of Mangoro River, 960 m asl, 19°05∞53∞∞S, 48°14∞00∞∞E, 23 October 1998 ( FMNH 5788 ) . One male (cw 23 mm), three juveniles (cw <10 mm), Lakato road, basin of Rianila River, 1050 m asl, 19°03∞07∞∞S, 48°21∞38∞∞E, 26 October 1998 ( FMNH 5789 ) . One male (cw 21.7 mm), Sahatandra River, cascade de Lakato, basin of Rianila River, 975 m asl, 19°01∞35∞∞S, 48°20∞39∞∞E, 26 October 1998 ( FMNH 5790 ) . Four juveniles, Lakato road, basin of Rianila River, 1050 m asl, 19°02∞40∞∞S, 48°21∞48∞∞E, 27 October 1998 ( FMNH 5791 ) . One male (cw 27.3 mm), Sahatandra River, 200 m before the bridge, basin of Rianila River, 1050 m asl, 19°02∞40∞∞S, 48°21∞43∞∞E, 27 October 1998 ( FMNH 5792 ) . Four males (cws 28.1, 28.8, 29, 30.5 mm) ( FMNH 5793 ) . Five juveniles, 15 km east of Morarano , basin of Rianila River, 975 m asl, 18°40∞35∞∞S, 48°22∞21∞∞E, 7 November 1998 ( FMNH 5794 ) . Two males (cws 11.7, 26.1 mm), 15 km east of Morarano , basin of Rianila River, 980 m asl, 18°40∞32∞∞S, 48°22∞21∞∞E, 6 November 1998 ( FMNH 5795 ) . One juvenile, 15 km east of Morarano , basin of Rianila River, 975 m asl, 18°40∞35∞∞S, 48°22∞21∞∞E, 7 November 1998 ( FMNH 5796 ) . One male (cw 21 mm), one juvenile (cw <10 mm), camp on road to Lakato, basin of Rianila River, 1075 m asl, 19°03∞30∞∞S, 48°21∞50∞∞E, 17 November 1998 ( FMNH 5797 ) . Two males (cws 14.4, 22.5 mm), five juveniles (cws <10 mm), Lakato road, basin of Rianila River, 1050 m asl, 19°02∞40∞∞S, 48°21∞48∞∞E, 18 November 1998 ( FMNH 5798 ) . Two males (cws 16.9, 17.3 mm), five juveniles (cws <10 mm), road to Lakato, basin of Rianila River, 0 m asl, 19°03∞31∞∞S, 48°21∞52∞∞E, 19 November 1998 ( FMNH 5799 ) . One juvenile, camp on road to Lakato, 19°03∞30∞∞S, 48°21∞50∞∞E, 19 October 1995 ( FMNH 5800 ) . One juvenile, camp on road to Lakato, basin of Rianila River, 1075 m asl, 19°03∞30∞∞S, 48°21∞50∞∞E, 10 December 1998 ( FMNH 5801 ) . Four males (cws 14.1, 16.8, 17.6, 21.7 mm), Iantara River, basin of Manampatrana River, Andringitra, camp I, 1350 m asl, 22°13∞28∞∞S, 47°01∞50∞∞E, 17 November 1993 ( FMNH 5810 ) . One male (cw 26.8 mm), one juvenile (cw <10 mm) Lakato road, basin of Rianila River, 1050 m asl, 19°02∞40∞∞S, 48°21∞48∞∞E, 18 November 1998 ( FMNH 5811 ) .

All coll. S. M. Goodman. One male (cw 44.9 mm), Amaringilra , 20 November 1993 ( FMNH 5713 ) . One male (cw 21.2 mm) ( FMNH 5714 ) . One juvenile ( FMNH 5717 ) . Three males (cws 42.1, 42.6, 42.7 mm) ( FMNH 5719 ) . Two males (cws 17.5, 30.6 mm) basin of Rianila River, 19°02∞49∞∞S, 48°21∞55∞∞E, 16 March 1995 ( FMNH 5740 ) . One male (cw 17.6 mm), basin of Rianila River, Lakato road, 18°58∞17∞∞S, 48°21∞03∞∞E, 19 October 1995 ( FMNH 5757 ) . Four males (cws 17.2, 18.2, 18.5, 23.4 mm), one juvenile (cw <10 mm) ( FMNH 5806 ) . Five males (cws 20.1, 24.6, 25, 25.3, 29.1 mm) ( FMNH 5807 ) .

Distribution. Hydrothelphusa agilis is found in the streams and rivers mainly in the northern, central and south-eastern regions of the island (in Fianarantsoa, Antananarivo, Toamasina and Antsiranana Provinces) (figure 2A). Figure 2A includes a total of 53 different localities for H. agilis from the present study and from the literature (Rabeharisoa, 1996; Cumberlidge, 1997; Cumberlidge and Boyko, 2001; Cumberlidge and Sternberg, 2002). Hydrothelphusa agilis is found in the rivers and streams of eight major river basins in five out of six Madagascan provinces in latitudes between 12° and 22°S, and from a lake near Mandraka, Toamasina Province (Cumberlidge and Sternberg, 2002). These river drainages are Antongombato (Antsiranana Province), Betsiboka (Antananarivo Province), Namorona and Manampatrana (Fianarantsoa Province), and Rianila, Mangoro, Ivondro and Sakanila (Toamasina Province). There are no records for this species from Mahajanga Province. The localities in the Betsiboka river basin are all at high elevations (1220–1370 m asl) in the clean fast-flowing tributaries of the highlands of Antananarivo Province. Hydrothelphusa agilis has been collected from a range of elevations from sea level (a stream in the drainage of the Rianila River) to 1800 m asl in the headwaters of the Tsiribihina River.

Remarks. Hydrothelphusa agilis is a large and common species, whose adult size ranges from carapace widths of 45–76 mm. The frontal margin of its carapace is diagnostic: horizontal and undeflexed, deeply indented and distinctly toothed. In addition, the suborbital margin is strongly toothed, as is the cheliped ischium. All of these characters serve to separate it from the three other species in the genus. Hydrothelphusa agilis is sympatric with H. madagascariensis in the Ambatandrano River in the Manampatrana river basin in Andringitra (775 m asl), and in the Iantara River (1370 m asl) (FMNH 5728, 5735).

Conservation status. Hydrothelphusa agilis is a widespread and abundant species, has been collected recently and its conservation status is secure ( table 1). This species is found in a number of protected areas including the Parc National d’Andasibe- Mantadia (Périnet-Réserve), the Parc National de Ranomafana, the Parc National d’Andringitra and the Parc National de la Montagne d’Ambre.