Foza manonae, Cumberlidge & Klaus & Meyer & Koppin, 2015

Cumberlidge, Neil, Klaus, Sebastian, Meyer, Kirstin S. & Koppin, Jennifer C., 2015, New collections of freshwater crabs from northern Madagascar, with the description of a new species of Foza Reed & Cumberlidge, 2006 (Brachyura, Potamonautidae), and comments on their conservation status, European Journal of Taxonomy 109, pp. 1-15 : 3-9

Foza manonae sp. nov.

urn:lsid:zoobank.org:act:B73D6977-4FF3-4C7A-A2ED-8CED73466A54

Figs 1–3 , Table 1

Diagnosis

Mid-proximal portion of G1 terminal article widened laterally by rounded lobe; s3/s4 incomplete, faint in middle deep at sides; anterolateral and posterolateral surfaces of carapace with conspicuous carinae; subhepatic region of carapace sidewall with carinae; anterior pterygostomial region of carapace sidewall heavily granulated.

Etymology

The new species is named for the first author’s late wife, Dr. Louise Manon Bourgault, in recognition of her numerous contributions to freshwater crab biology during her time spent researching communication in Africa and Madagascar.

Material examined

Holotype

MADAGASCAR: Adult ♂, Antsiranana Province, Ankarana Special Reserve , 12.92° S, 49.14° E, near pitfall trap site, coll. F. Glaw, M. Franzen, J. Köhler & N. d’Cruze, 13 Feb. 2008 (CW 43.7, CL 32.6, CH 18.7, FW 10.5) ( ZSM A20145003 ).

Paratype

MADAGASCAR: Adult ♀, Antsiranana Province, same locality (CW 42.4, CL 32.2, CH 18.3, FW 10.4) ( ZSM A20145004).

Other material examined

MADAGASCAR: Sub-adult ♀, Antsiranana Province, Montagne des Français Reserve, 12.34° S, 49.35° E, in pitfall trap, coll. N. d’Cruze et al., 19 Feb. 2008 (CW 36.9, CL 29.0, CH 15.8, FW 9.0) ( ZSM A20145005); juvenile, same locality (CW 12.1, CL 10.4, CH 5.8, FW 4.6) ( ZSM A20145006).

Description

Based on holotype (adult ♂, CW 43.7). Carapace outline transversely oval, high ( CH /FW 1.75); front narrow (FW/CW 0.28), deflexed; epibranchial tooth small, pointed, extremely advanced in position; anterolateral margin evenly curved outward, lined by small granules; postfrontal crest faint, incomplete postorbital crests, epigastric crests well defined, positioned forward on front; deep wide mid-groove between epigastric crests; cardiac urogastric grooves deep, cervical grooves deep posteriorly, faint anteriorly, long, almost reaching postfrontal crest. Anterolateral and posterolateral surfaces of carapace with conspicuous carinae. Suborbital region of carapace sidewall with small granules, subhepatic region with carinae, pterygostomial region heavily granulated with setae in inferior part; vertical sulcus on carapace sidewall curved, granular, running from base of epibranchial tooth to epimeral sulcus.Epistomial tooth triangular, deflexed, edges smooth. Exopod of third maxilliped long, reaching ischium/merus junction, flagellum of exopod long, ischium with deep vertical groove. Mandibular palp 2-segmented with small, hard, rounded lobe at junction between segments, lobe one-third length of terminal segment. s1/s2 short, very faint; s2/s3 deep, wide, completely crossing sternum; s3/s4 incomplete, faint in middle deep at sides. Episternal sulci s4/e4, s5/e5, s6/e6, s7/e7 absent. Male abdomen triangular, tapered, widest at a3, narrowest at a7 (telson); telson outline forming straight-sided triangle with broad base, rounded apex. Sternal grooves s4/s5 meeting telson just beyond abdominal groove between a7/a6; sternal grooves s5/s6 meeting a6 one half somite length from a6/a5; sternal grooves s6/s7 meeting a5 one third somite length from a5/a4.

G1 terminal article short (ratio of length of terminal article to subterminal segment 0.27), cone-shaped, straight, tapering to broad tip, apical opening narrow, directed slightly outward, smooth; mid-proximal portion of G1 terminal article widened laterally by rounded lobe; lateral, medial folds basally separated, meeting midway along ventral face, forming longitudinal groove that continues almost to tip of article; groove not visible on dorsal face. Subterminal segment of G1 with raised rounded shoulder on lateral margin near junction with terminal article. Terminal article/subterminal segment junction of G1 marked by faint diagonal line on ventral side, dorsal side marked by broad, subtriangular dorsal membrane; superior margin of dorsal membrane formed by horizontal basal margin of terminal article, inferior margin of membrane formed by U-shaped distal edge of subterminal segment; lateral, medial margins of dorsal membrane narrow. Terminal article of G2 flagellum-like, long, reaching anterior margin of sternoabdominal cavity; flagellae of G2 viewed together in situ forming heart shape; distal parts of terminal articles of both G2s touching, sometimes protruding from under closed abdominal telson.

Movable finger (dactylus) of major (right) cheliped slender, upper margin smooth. Fixed finger long, ⅓ height of palm; lower margin of palm slightly indented; proximal region of cutting edge of fixed finger with four large, fused molars followed distally by series of small teeth. Carpus with two teeth on inner margin, first tooth large, pointed, second tooth smaller, pointed, followed by series of very small teeth. Medial, lateral margins of inferior face of cheliped merus distinctly toothed, inferior face with pointed, granulated, distal tooth; superior margin and superior face of merus covered with granules and short carinae; granules on medial margin of merus continuous with granules on medial margin of cheliped ischium, inferior margin of ischium rounded, smooth. Walking legs (p2–p5) of normal length, not strikingly elongated, inner margins of propodi of p2 to p5 smooth.

Size

The largest known specimen is the male holotype, CW 43.7. Adults judged by size at pubertal molt are between CW 37 and CW 42.

Type locality

Ankarana Special Reserve, 12.92° S, 49.14° E, Antsiranana Province, northern Madagascar.

Distribution

Foza manonae sp. nov. is known only from two localities in Antsiranana Province in northern Madagascar: Ankarana Special Reserve and Montagne des Français Reserve ( Fig. 4 ).

Ecology

At the Ankarana Special Reserve the new species is found in sympatry with two other species of freshwater crabs: Foza ambohitra (ZSM A20145001, ZSM A20145002) and Madagapotamon humberti (ZSM A20145007, ZSM A20145008, ZSM A20145009, ZSM A20145010). Foza manonae sp. nov. is also found in sympatry with M. humberti (ZSM A20145012) at Montagne des Français Reserve, where the two species were caught together in pitfall traps. Both F. ambohitra and M. humberti are known to be semi-terrestrial air-breathing crabs ( Cumberlidge & Meyer 2009), so it is likely that F. manonae sp. nov. also has similar habits and abilities, and also has a similar degree of independence from permanent water sources. Furthermore, the branchial chambers of F. manonae sp. nov. (like those of F. ambohitra ) each house two different sets of respiratory organs: a dorsal pseudolung for aerial respiration and ventral gills for aquatic respiration ( Sternberg & Cumberlidge 2001).

Remarks

The differences between Foza and the other Malagasy freshwater crab genera are discussed by Reed & Cumberlidge (2006), Cumberlidge & Meyer (2009), and Meyer et al. (2014). Foza manonae sp. nov. is assigned to the genus Foza on the basis of characters that it shares with F. raimundi Reed & Cumberlidge, 2006 , the type species of the genus ( Reed & Cumberlidge 2006). These characters include a bilobed mandibular palp, a faint postfrontal crest, sternal grooves s6/s7 that meet the margin of abdominal segment a 5 in the middle of the segment, and curved, elongated G2s that together form a distinctive heart shape ( Fig. 2A ). A preliminary DNA comparison of 16S rRNA sequences of F. manonae sp. nov. with those of other Malagasy freshwater crab species available from GenBank was made by the second author (SK, unpublished data). The results positioned the new species in a separate clade, although the taxonomic sampling and exact identity of the species to which the other sequences belong is currently the focus of a larger molecular phylogenetic study of the Malagasy freshwater crab fauna using a wider range of molecular markers (S.R. Daniels, pers. comm.).

The four species of Foza are compared in Table 1 and can be identified as follows: Foza manonae sp. nov. can be distinguished from F. raimundi Reed & Cumberlidge, 2006 by the texture of the anterolateral surfaces of the carapace (which have heavy carinae in F. manonae sp. nov. but are smooth, or with only a few light carinae in F. raimundi ), by the texture of the suborbital and subhepatic regions of the carapace sidewall (which have granules and/or carinae in F. manonae sp. nov. but are smooth in F. raimundi ), by the terminal article of G1 (which is cone-shaped in F. manonae sp. nov. and tube-shaped in F. raimundi ), by the pterygostomial region and the sternoabdominal cavity (which largely lack setae in F. manonae sp. nov. but have dense fields of setae in F. raimundi ), and by the sternal sulcus s3/s4 (which is incomplete and only visible at the sides in F. manonae sp. nov., but complete and crossing the entire thoracic sternum in F. raimundi ).

Foza manonae sp. nov. can be distinguished from F. ambohitra by the texture of the posterolateral corners of the carapace (which have heavy carinae in F. manonae sp. nov., but are smooth with a few light carinae in F. ambohitra ), by the texture of the suborbital and subhepatic regions of the carapace sidewall (which have granules and/or carinae in F. manonae sp. nov., but are smooth in F. ambohitra ), by the suborbital and subhepatic regions of the carapace sidewall (which are granulated in F. manonae sp. nov., but smooth in F. ambohitra ), and by the terminal article of G1 (which is widened in F. manonae sp. nov., but slim and evenly tapered in F. ambohitra ).

Foza manonae sp. nov. can be distinguished from F. goudoti by the postfrontal crest (which is faint and incomplete in F. manonae sp. nov., but distinct and completely crosses the carapace in F. goudoti ), by the anterolateral surfaces of the carapace (which have heavy carinae in F. manonae sp. nov., but are smooth or with only a few light carinae in F. goudoti ), by the subhepatic region of the carapace sidewall (which has carinae in F. manonae sp. nov., but is smooth in F. goudoti ), and by the terminal articles of G2 (which are curved distally, forming a distinctive heart shape in F. manonae sp. nov., but are slim, long, and straight in F. goudoti ).

Figures

Fig. 1. Foza manonae sp. nov. Holotype, adult ♂, CW 43.7 mm, Ankarana Special Reserve, Madagascar (ZSM A20145003). A. Carapace, frontal view. B. Carapace, dorsal view. C. Third maxilliped, ventral view. D. Carpus and merus of cheliped, dorsal view. E. Carpus and merus of cheliped, ventral view. F. Right cheliped, frontal view. G. Left cheliped, frontal view.

Fig. 2. Foza manonae sp. nov. Holotype, adult ♂, CW 43.7 mm, Ankarana Special Reserve, Madagascar (ZSM A20145003). A. Left and right G1 and G2 shown in situ in ventral view. B. Left G1, dorsal view. C. Left G1, ventral view. D. Sternum and abdomen, ventral view. E. Left mandibular palp, superior view. F. Left mandibular palp, frontal view. Scale bar: 14 mm (A–B, E), 23.2 mm (C–D).

Fig. 3. Foza manonae sp. nov. Holotype, adult ♂, CW 43.7 mm, Ankarana Special Reserve, Madagascar (ZSM A20145003). Entire animal. A. Dorsal view. B. Frontal view. C. Sternal view. Scale bar: 14.6 mm.

Fig. 4. Distribution map of northern Madagascar showing the seven localities (black circles) where freshwater crabs were collected in the present study: Foza manonae sp. nov. (white circles), F. ambohitra (triangle), and Madagapotamon humberti (squares).

Tables

Table 1. Comparison of the morphological characters of the species in the genus Foza.

Character	F. raimundi	F. goudoti	F. ambohitra	F. manonae sp. nov.
Postfrontal crest	faint	distinct	faint	faint
Anterolateral surface of carapace	smooth, light carapace	smooth	smooth, light carapace	heavy carinae
Postlateral surface of carapace	light carinae	light carinae	smooth	heavy carinae
Cervical grooves	short	long	long	long
Suborbital region	smooth	large granules	smooth	small granules
Subhepatic region	smooth	smooth	smooth	carinae
Anterior pterygo- stomial region	dense setae all over	inferior region with setae	inferior region with setae	inferior region with setae
Anterior pterygo- stomial region	smooth	superior region with granules	superior region with granules	heavily granulated all over
G1 terminal article	tube-shaped, not widened	cone-shaped, not widened	cone-shaped, not widened	cone-shaped, laterally widened by raised lobe
G2 terminal segment	left one shaped like question mark, together form heart shape	straight, long, no distal curve	left one shaped like question mark, together form heart shape	left one shaped like question mark, toge- ther form heart shape
Sternoabdominal cavity	dense setae	no/few setae	no/few setae	no/few setae
s3/s4	complete, u-shaped	complete, v-shaped	complete, u-shaped	shallow in middle, deep at sides
s6/s7 meets a5	at middle margins of somite	at a5/a6 junction	at a5/a6 junction	at middle margins of somite
Major cheliped proximal propodus	one molar	3–4 molars	3–4 molars	3–4 molars