Minuca panema ( Coelho, 1972 )

Thurman, Carl. L., Shih, Hsi-Te & McNamara, John C., 2023, Tuerkayana latens Ng and Hsi-Te Shih 2023, n. sp., Zoological Studies 62 (45), pp. 1-26 : 6-14

Minuca panema ( Coelho, 1972) ( Figs. 1 , 3–7 )

Ciecie panema Marcgrave 1648: 185 (list; Brazil).

Cancer vocans minor Herbst 1782: 81 (= Gelasimus annulipes H. Milne Edwards, 1837 ; see Shih et al. 2021) (not Gelasimus annulipes H. Milne Edwards, 1837 ).

Uca panema Coelho, 1972: 42 [Pernambuco, Paraíba]; Coelho and Coelho-Filho 1993: 48 [key; Brazil]; Coelho 1995: 139 [list]; Shih et al. 2016: 154 [list]; Questel 2019: 28 [list].

Uca (Minuca) burgersi – Crane 1975: 168–172, 604 [part, list; Brazil]; Almeida et al. 2010: 354 [ Brazil]; Bezerra 2012: 216–219 [part, list; Brazil]; Thurman et al. 2013: 6, 8, 9, fig. 1 [list; Brazil].

Uca burgersi – von Hagen 1983: 230 [part; Brazil]; von Hagen 1984: 205 [ Trinidad]; Almeida and Coelho 2008: 207 [ Brazil].

Minuca burgersi – Shih et al. 2016: 143, 154, fig. 3; Thurman et al. 2017: 247–250, tables 1–5, figs. 3, 5, 6, [ Brazil]; Rosenberg 2019: 735 [list]; Thurman et al. 2021: 1–28 [South America].

Material examined: Minuca panema ( Table S1):

Neotype: male 11.55 × 8.24 mm ( MZUSP 42510 ), Brazil, Pernambuco, Rio Maracaípé. Others: Trinidad: ( RMNH 23040 ), Blanchisseuse ( USNM 138505 ), L. Ebranche River ( RMNH 23040 , UNI 722 ), Burro River , Invader’s Bay ( UNI 721 , 720 ), Cocorite Swamp ( USNM 137745 ); Brazil: Pará, Curuçá ( MZUSP 12313 ); Maranhão, Icatú ( MZUSP 23176 ); Ceará, Fortaleza ( USNM 138509 ) ( MZUSP 23179 ); Paraíba, Mamanguape ( MZUSP 13255 ); Pernambuco, Rio Maracaípé ( MZUSP 20838 and 20841); Bahia, Itaparica ( USNM 138510 ), Madre de Deus : Plataforma Lobato ( MZUSP 20834 , 20844 ); Espírito Santo: Conceição ( MZUSP 18650 ), Anchieta ( MZUSP 18638 ), Santa Cruz: Bairro Joana D’Arc: Guarapari ( MZUSP 20837 , 20840 , 20842 , 20990 , 20991 ); Rio de Janeiro: Ilha do Pinheiro ( USNM 138511 ), Ilha de Paquetá ( USNM 19971 ), Itacuruçá ( MZUSP 17201 ), Barra de Guaratiba ( MZUSP 20839 ); São Paulo: Ilhabela ( USNM 136004 ), Santos ( USNM 138512 ), São Sebastião, Bertioga ( USNM 1136004 , MZUSP 20834 , 20835 , 20839 , 23177 , 23178 ); Paraná: Baía de Guaratuba : Ponta de Venda ( ZMUSP 42511 ), Baía de Guaratuba ( MZUSP 20833 ); Santa Catarina: Rio Itajaí-Mirim : Balneário Daniela: Barra da Lagoa : Praia da Armação ( MZUSP 20828 , 20829 , 20830 , 20831 , 20832 ).

Comparative material: Minuca burgersi ( Holthuis, 1967) ( Table S1): Netherlands Antilles: Curaçao: Grote Knip ( RMNH 23012 (holotype); USNM 121099 (paratype), 7577; UNI 719); Aruba ( USNM 138503); Leeward Islands: Sint Maarten ( USNM 138497, 138498); Tobago: Pigeon Point ( USNM 138504); Barbados, St. Peter’s Bay, Maycock’s Bay, Graeme Hall ( UNI 716, 717, 718).

Description ( Fig. 3 ): Carapace trapezoidal, surface strongly convex, smooth and glossy with numerous small pits. Front angled from midline to lateral margin about 16°. Eyebrows barely visible ( Fig. 3A : a). Length of carapace 68% width in females (n = 108) and 66% in males (n = 401). H-depression deep with some pubescence and two large central pores in sulcus. Frontal region compared to carapace width 37.1% or greater (n = 10). Sulcus posterior to orbits deep ( Fig. 3A : b). Lower orbital margin with rectangular dentals ( Fig. 3F : c). Anterolateral angles ( Fig. 3A : d, Fig. 3B : d) sharp, pointed inward toward medial line. Hepatic area swollen and rounded behind angle. Anterior edge of lateral line almost straight forming smooth, obtuse angle with posterior lateral line ( Fig. 3B : e). Two posterolateral striae ( Fig. 3B : f) present. Dorsal striae long and fragmented into two parts. Second more ventral and shorter. Patch of pubescence ( Fig. 3B : g) between striae and ventral edge of carapace. Outer surface of major cheliped with dorsal ridge on manus. Large tubercles on upper manus decreased in size to ventral margin ( Fig. 3C ). Dactyl articulation joint ( Fig. 3C : h) with row of tubercles. Base of pollex at manus forming smooth triangular sulcus ( Fig. 3C : i). Pollex ( Fig. 3C : j) and dactyl ( Fig. 3C : k) horizontally compressed, blade like with smooth surfaces. Three rows of tubercles in gap. End of pollex trifurcated with three tooth-like tubercles. Dactyl with two larger tubercles ( Fig. 3C : k, Fig. 4A : a); one proximal and the other distal. Pollex with large tubercle on distal half followed by second smaller tubercle ( Fig. 3C : j). Inner surface of major cheliped with carina of tubercles lining dorsal edge of carpal cavity ( Fig. 3D : l). Carina often ending in a patch of tubercles with upper row pointed to dactyl. A smooth triangular area above the carina terminus. Lower edge of carpal cavity with apex of tubercles at proximal end of oblique ridge ( Fig. 3D : m). Distally oblique ridge across palm undeveloped. Dactyl joint with row of 5–8 tubercles ( Fig. 3D : o). Lines of tubercles on predactyl and articulating ridges not parallel. Predactyl ridge forming crescent arch initially extending toward palm but returns to articulation ( Fig. 3D : n). Keel on lower edge of manus and ventral pollex. Exterior surface of minor cheliped smooth. Long ridge from manus to end of pollex. Dactyl with faint ridge from articulating junction to terminus. Pollex and dactyl with 6–8 sawtooth tubercles in gap. Distal tips of dactyl and pollex with sharp, chitinized edge. On inner surface of pollex and dactyl, distal end with regularly arranged comb-like setae covering about one-third of pollex length. Width of merus on ambulatory legs 1–3 of minor side ( Fig. 3E ) approximately 37% of length (n = 10). Dorsal and lateral surfaces of carpus and manus on ambulatory legs 1–3 of with pubescence ( Fig. 3E : q). Dorsal surface of dactyl without pubescence. No pubescence on ventral surface of manus, carpus or dactyl. Long setae ( Fig. 3E : r) plentiful on manus but sparse on merus. Distal end of G 1 with long setae ( Fig. 5A : a, b; Fig. 5B, C ). Proximal group few in number but long (0.5 to 0.75 mm) ( Fig. 5C ). A few setae near terminal flange. Flange with pronounced cusp ( Fig. 6A : a; Fig. 6B : a). In females, operculum of vulvae small and protruding, no tubercle ( Fig. 7A ).

Remarks ( Figs. 4 , 7 ; Table 2): The relationship of M. panema to other species in the Minuca genus is addressed in the “DISCUSSION” section. Since they are geminate species, here, we focus on the subtle anatomical landmarks distinguishing M. panema from M. burgersi sensu stricto ( Table 2). For males, there are two or three large tubercles ( Fig. 4A : a) at the distal end of the cheliped pollex in M. panema . In M. burgersi sensu stricto, there is usually only one tubercle ( Fig. 4B : a) on the pollex. Minuca panema has a prominent smooth sulcus on the lateral surface of the major cheliped at the pollex-manus junction ( Fig. 4A : b). Tubercles on the lateral surface of the manus form a distinct pre-dactyl ridge ( Fig. 4A : c) in M. panema . In M. burgersi , the ridge is weak (Fig. B: c). On the medial inner surface of cheliped, oblique tubercle ridges are more clearly defined in M. panema ( Fig. 4C : d). The carina ( Fig. 4C : e) along the lower edge of the carpal cavity are more distinct in M. panema . The carina along the upper edge of the carpal cavity terminates in a tubercle field ( Fig. 4C : f) that expands to the medial predactyl ridge. The pre-dactyl ridge ( Fig. 4C : g) arches strongly and intersects with the tubercle ridge on the swelling of at the articulating joint in M. panema . In M. burgersi , the oblique ridge ( Fig. 4D : d) is less developed and the inferior carpal carina has only a few tubercles ( Fig. 4D : e). The field of tubercles at the distal end of superior carpal carina ( Fig. 4D : f) does not extend to the pre-dactyl ridge. This area is usually smooth.

Figures 5 and 6 are images of the right G 1 from Minuca panema and M. burgersi . In figure 5, the former, G 1 is ornamented with setae that have been removed in figure 6. In M. panema , setae near G 1 tip ( Fig. 5A–C )

Characters M. burgersi M. panema

Eye orbits From dorsal view, ocular cavities angled to posterior. Eyebrows Ocular cavities not strongly angled. Eyebrows visible. Dorsal carina lightly beaded, lower strongly beaded. visible. Upper and lower carina almost smooth.

Carapace surface Surface finely granular with pits. Post-orbital sulcus deep. Medially Surface finely granular with pits. Post-orbital with tubercle. Laterally curved to intersect dorsal lateral margin. sulcus deep. Medial end curving toward H-depression deep. Interocular lobe formed about 34.0 ± 1.3% H-depression. Large tubercle at antero-

of carapace width. Eyestalks short with 25% retina. From front, and medial sulcus. H-depression shallow.

carapace arched. Interocular lobe 37.8 ± 3.0% carapace width. Eyestalks like M. burgersi . From front carapace flat.

Orbital floor Floor smooth. Lateral ends with 3-sharp tubercles surround by Floor smooth. Lateral ends with 2-tubercles.

short setae. Lower edge with rectangular dentals. Setae behind Lower edge with rectangular dentals. Setae dentals. behind line of dentals.

Anterolateral angle Anterolateral angles pointed forward but converging toward body Same as M. burgersi .

midline.

Anterolateral, dorsolateral Anterolateral margins intersecting with dorsolateral margin at widest Margin lines strongly tuberculated. Otherwise and vertical lateral portion of carapace. Lines almost smooth. 2 posterolateral striae margins very similar.

margins present. Anterolateral margins diverging into vertical lateral margin. This terminating between 3rd and 4th ambulatory legs.

Major cheliped outer surface Outer surface: Dorsal surface with two parallel ridges of tubercles. Parallel tubercle ridges on dorsal surface weakly Outer upper surface with large tubercles decreasing in size developed. Sulcus at pollex-manus junction.

ventrally. Ventral margin with a tubercle ridge.

predactylar ridge Predactylar articulation joint weakly developed. No tubercles on predactylar joint.

pollex Pollex face smooth with pits. One tooth about 2/3 distance of Teeth on dorsal edge of pollex same as M.

pollex. Terminus with 3 teeth. 3 rows of teeth on dorsal edge of burgersi .

pollex.

dactyl Dactyl blade-like with variable number of teeth in gap and no Dactyl blade-like and smooth. Others same as M. grooves. Rows of tubercles on anterior and posterior edge. burgersi .

Random teeth between.

inner dactyl At articulation, 2 predactylar ridges diverging dorsally. Surface 2 diverging predactylar ridges. Surface smooth.

smooth.

inner palm surface Dorsal carina completely outlining carpal cavity. Tubercle ridge Carpal carina ending in a patch of 10–20 large diverging point to dactyl. Triangle above carina smooth. Palm tubercles above apex of oblique ridge. Few with high tubercle ridge running obliquely. tubercles connecting apex and carina.

Minor chela Dorsal surface with ridge. Outer surface smooth. Depression below Outer surface smooth. Dorsal surface of dactyl dactyl articulation. Strong line on pollex. Teeth in gap small. with small ridge. Pollex with Ridge. 3–5 Distal 3–4 largest. Distal end of minor claw ridged and sharp. teeth in gap. Tip of pollex and dactyl rigid Inner surface smooth. 4–5 long setae on distal end of pollex. and sharp. Inner palm smooth. Long setae on Carpus with numerous vertical lines of tubercles on posterior inner faces of both dactyl and pollex. Carpus face. Merus with numerous rows of vertical tubercles on smooth. Merus with short row of tubercles.

posterior surface.

stridulation ridges on 1st Face of adjacent 1st ambulatory leg without stridulating apparatus. No obvious stridulation apparatus on 1st

ambulatory leg ambulatory leg.

Ambulatory legs Manus and carpus with pubescence and long setae on dorsal Dorsal surface of manus and carpus wit surface. Merus and ischium with short setae. Longer setae on pubescence and long setae. No pubescence on ventral surface. Merus width about 1/3 segment length. 4th ambulatory leg. Ventral surface smooth with long setae. Proximal merus with short setae.

G 1 ( Crane 1975: fig. 66 F) G 1 with setae near terminus. Terminal flange dark and semi- Few long setae. Deep cusp in flange.

cylindrical. Pre-terminal palp present.

Vulva ( Crane 1975: fig. Sternal opening covered by bulging plate. No protruding tubercle. Sternal opening covered by bulging plate. No

54 G) protruding tubercle.

Live color carapace Dorsal carapace surface purple to brown. H-depression large, red- Dorsal surface gray with white spots.

brown. Lower carapace dark chocolate brown. H-depression thin, bright red. Lower carapace cherry red-brown.

cheliped Cheliped dark red-orange. Fingers off-white. Cheliped yellow-orange. Fingers light in color.

ambulatory legs Legs brown, carpus and manus banded. Legs proximally red, distally light brown tan.

are few in number but very long. In M. burgersi ( Fig. 5D–F ), the setae are shorter and form a wide, brushlike structure. When the setae are removed ( Fig. 6 ), the apical flange and “thumb” are easier to see. Both Chase and Hobbs (1969: p 210, fig. 71a, b) and Crane (1975: p 380, fig. 66 F) provided drawings of the naked tip. In M. panema , the terminal edge of the flange (a) is deeply incised with a cusp ( Fig. 6A, B ) while the indentation is shallow in M. burgersi ( Fig. 6C, D ). Both species have a thumb-like palp ( Fig. 6B : b, Fig. 6D : b) on the anterior surface of G 1.

For females, the vulvae are similar ( Fig. 7A, B ). A cover or operculum bulges outward slightly but with no prominent tubercle ( Fig. 7A, B ). A small posterior rim is present in both species. In females of similar carapace widths, diameter of vulva is about 0.20 mm for M. burgersi but smaller in M. panema (about 0.12–0.15 mm).

Etymology: The specific name honors the original designation by Marcgrave (1648) in reference to the species’ common name at that time, “ Ciecie Panema ” or “Cranguersinho des Manges”.

Geographical range ( Fig. 2 ): Eastern coast of South America from Trinidad Island to Praia da Armação, Santa Catarina, Brazil.

Color in life: Anterior portion of carapace mottled in smudgy gray or blue gray ( Fig. 1A ). Posterior carapace “crimson” or “cherry” red. Major cheliped in male ochre-orange with pollex and dactyl near white. Proximal portion of ambulatory legs “crimson-red” with distal regions brown.

Habitat: Near the mouths of rivers, islands and estuaries. Most frequently colonizing red-brown clay to silty sand or sandy clay in the upper or supratidal zone. Habitats are oligo- to mesohaline (0.6 to 36.3 psu; 18 to 1,037 mOsm kg -1 H 2 O) with a modal value of 7.7 psu (220 mOsm kg -1 H 2 O) and a mean of 12.2 ± 2.7 psu (349 ± 79 mOsm kg -1 H 2 O). Found near mangroves ( Rhizophora sp. and Laguncularia sp. ) ( Coelho, 1972) but very common in open or low vegetation such as Batis maritima , Samolus sp. , Salicornia sp. and Disticilis sp. ( Thurman et al. 2013 2017).

Molecular analysis: The pairwise nucleotide divergences of COI with K 2 P distances and bp differences for Minuca panema , M. burgersi sensu stricto, M. aff. burgersi and M. mordax are given in table 3. The intraspecific and interspecific divergences of COI are ≤ 2.81% (18 bp) and ≥ 4.61% (29 bp), respectively. The phylogenetic tree based on combined 16 S, COI and 28 S sequences ( Fig. 8 ) shows that the Neotropical species forming the genus Minuca are monophyletic. Minuca brevifrons (Stimpson, 1860) appears as a basal species. Three taxa, M. burgersi , M. panema and M. aff. burgersi cluster together with

M. mordax forming a clade of related species. Three additional clades of related species appear within the genus Minuca : 1) zacae , 2) vocator-ecuadoriensis-osa, 3) pugnax-argillicola-victoriana-marguerita-minaxlongisignalis -herradurensis-galapagensis-rapax-virens.

Figures

Fig. 1. A: Minuca panema (Coelho, 1972) and B: Male Minuca burgersi (Holthuis, 1967). A: From the South Atlantic Ocean – Brazil, São Paulo state, Caraguatatuba, Praia da Enseada (23.726°S, 45.419°W) (ZMUSP 20835). B: From type location, Caribbean – The Netherlands Antilles, Curaçao, Westpunt, Grote Knip, salt pond (12.352°N, 69.15122°W) (UNI 721). Scale bar = 10 mm.

Fig. 3. Minuca panema (Coelho, 1972) (ZMUSP 20833). A: Dorsal view. B: Lateral carapace view on side of minor cheliped. C: Outer surface of major cheliped. D: Inner surface of major cheliped. E: Second ambulatory leg. F: Oral view of carapace. a. eyebrow, b. postorbital sulcus, c. dental on suborbital margin, d. anterolateral angle, e. posterolateral line, f. posterolateral striae, g. pubescence, h. articulation ridge, i. pre-pollex depression, j. pollex, k. dactyl, l. superior carpal cavity carina, m. apex of oblique ridge, n. pre-dactyl ridge, o. articulation ridge, p. manus-pollex ridge, q. pubescence, r. setae. Scale bar = 10.0 mm.

Fig. 4. Comparison of male major cheliped between Minuca panema (Coelho, 1972) (A, C; MZUSP 20833) and M. burgersi (Holthuis, 1967) (B, D; UNI 719). A, B: outer surface, C, D: inner surface. a. tubercle at distal end of pollex, b. sulcus at pollex-manus junction, c. lateral predactylar tubercle ridge, d. oblique palmar tubercle ridge, e. anterior of carpal cavity, f. tubercle field, g. medial predactylar ridge. Ruler with 1 mm divisions at upper edge of figure 5A, B.

Fig. 5. Male right G1 tip with setae from Minuca panema (Coelho, 1972) (A, B, C; MZUSP 20833) and M. burgersi (Holthuis, 1967) (D, E, F; UNI 719). A, D, posterior view, B, E, anterior view, C, F, lateral view of tip. a. terminal setae, b. terminal flange. Scale bar = 0.5 mm.

Fig. 6. Male right G1 from Minuca panema (Coelho, 1972) (A, B: MZUSP 20833) and M. burgersi (Holthuis, 1967) (C, D: UNI 719). a. apical flange, b. “thumb” or palp. Scale bar = 0.5 mm.

Fig. 7. Female vulva in Minuca panema (Coelho, 1972) (A: MZUSP 20833) and M. burgersi (Holthuis, 1967) (B: UNI 719). Arrow indicates left gonopore. Scale bar = 1.0 mm.

Fig. 2. Geographical distribution of Minuca burgersi (Holthuis, 1967) (blue; distributed Bahamas, Curaçao, Barbados), M. aff. burgersi (green; distributed Florida, Virgin Islands, Belize) and M. panema (Coelho, 1972) (red; Atlantic coast of South America: Trinidad Island to Florianópolis, Santa Catarina, Brazil). Modified from Thurman et al. (2021).

Fig. 8. Molecular phylogeny based on mitochondrial 16S and COI, as well as nuclear 28S for 19 species in the genus Minuca. The outgroups are Leptuca pugilator (Bosc, 1802) and Petruca panamensis (Stimpson, 1859).