Rev. Bio!. Trop., 35(2): 173-181, 1987.

Comparative behavior of Eurypanopeus depressus (Smith) and Eurypanopeus dissimilis (Benedict and Rathbun) (: Brachyura: Xanthidae).

Humberto A. Garcés B. Department ofBiologieal Seienees, Florida Atlantie University, Boca Raton, Florida, 33431, U.S.A.

(Reeeived December 19, 1985)

Abstraet: A series of experiments and observations were made on two nominate speeies of mud erabs. Differenees were found in desieeation resistanee, salinity toleranee, temperature toleranee, dominanee and eoexistenee, aggressiveness, feeding, and response to a new habitat. Data support the seheme of previous elassifieation, which regards them as separate species. It is eoncluded that Eurypanopeus depressus and Eurypanopeus dissimilis are two closely related sympatric species isolated by behavioral faetors.

The behavioral patterns of the are 1978) and the response of stage 1 zoea to gravi­ a..T1long the most varied and complex of the ty and thermal gradients (Kelly et al. 1980). . Unfortunately, relatively few beha­ The present investigation was done to detect vioral accounts exist for brachyurans despite and contrast differences in behavior of the two the abundance of species and the opportu­ closely related species, E. depressus (Srnith nity for comparative studies of their behavior 1869) and E. dissimilis (Benedict and Rathbun and ecology. 1891). Although both are considered different The genus Uea of the family Ocypodü.taehas species, E. dissimilis has not been reported in received the most ethologicai attention (Sal­ the literature since 1930 (Rathbun). It seems mon 1967; Crane 1975). Behavioral reports that E. dissimilis has been overlooked if not outside the genus Uea within the division confused with E. depressus in past studies. The­ Brachyura are scarce and almost absent within re are, however, subtle differences in morpholo­ the Xantid family. gy and distribution between both species. The Behavioral studies encountered within the main morphological characters that separate Xanthidae have been made on agonistic and se­ both species are carapace teeth shape, chela co­ xual behavior (Savage 1971; Hazlett 1976; and loration, and size of red spot on third maxilli­ Swartz 1976) and on larval behavior during ver­ pedo Furthermore, E. depressus is mostly a nor­ tical migration (Forward 1985). Within the ge­ thern species, occuring on both coasts from nus Eurypanopeus there are only a few studies Massachusetts Bay through Florida and to on E. depressus and none on E. dissimiJis. Stud­ southern Texas. It has also been reported from ies on adult E. depressus include the report on St. Martin, Dutch West Indies, Uruguay and desiccation tolerance and the exploitation of Bermuda (Williams 1984). Boca Raton is consi­ rnicrohabitat (Grant and McDonald 1979); dered a new locality record for E. depressus. electrophoretic variations (Turner and Alyerla According to Rathbun (1930), E. dissimilis oc­ 1980); allometric constraints and variables of curs in the Gulf of Mexico (west coast of Flori­ reproductive effort (Hines 1982); and behavio­ da on1y) down to Santa Catarina, Brazil,and in ral basis of depth regulation in hatching and Cuba, Jamaica, Tr inidad and Nicaragua. The oc­ post-larval stages (SuIkin et al. 1983). Behavio­ curence of E. dissimilis is recorded here for the ral responses of the larval stages of E. depressus frrst time since 1930 (Rathbun). The east coast have received some attention, such as: the er­ of Florida is considered a new record for distri­ fects of cadmium and mercury (Mirkes et al. bution and locality of the species.

173 174 REVISTA DE BIOLOGIA TROPICAL

MATERIAL AND METHODS kept in the laboratory at least five days prior to experimentation. CoIlections: Individuals of E. depressus and E. dissimilis were coIlected subtidalIy from Desiccation tolerance: AlI desiccation expe­ c1umps of shelI beds on a seawall canal. riments were carried out at room temperature Sampling was done in the canal between US-I (19.0 - 21.0 OC) in a glass desiccator, containing and the Intracoastal Waterway in northern Boca 50 g of color-indicating CaS04' Each crab was Raton, Palm Beach County, Florida, U.S.A. du­ placed in a 20 mI beaker inside the desÍCcator ring October and November, 1984. The canal to avoid contact with the desiccant. Crabs were fauna was composed mainly of Crassostrea vir­ weighed on a Cent-O�ram Ohaus balance. After ginica Gmelin, the American oyster, growing determination of wet weight (initial weight), over the concrete walls, dock pilings, and on were placed in the desiccator, weighed the bottom of the canal. The average salinity in initialIy at 60 mino intervals, and then weighed the canal (Mohr Titration) was 34.00/00, and at 30 mino intervals when near death. The time the average water temperature was 21.00C. A that the crabs spent out of the desiccator was surnmary of the colIection is presented in Table not inc1uded in the data. After death, animals l. Both species of Eurypanopeus were identi­ were dried at 100 oC fo r 24 hours, using a Pre­ fi ed by morphological characteristics outlined cision Thelco Oven Model 18, and weighed (dry by Rathbun (1930) and Williams (1984). Ray­ weight). The criterion for determining death mond B. Manning from the National Museum was the lack of response of the walking legs to (United States) verified both Eurypanopeus tactile stimulation (Grant and McDonald, species identification. Voucher specimens have 1979). After obtaining the dry weight the crabs been deposited at the United States National were measured with a Bel Art Caliper at the Museum (U.S.N.M.): E. depressus (U.s.N.M. widest part of the carapace to the nearest 0.01 Cato Nos. 233535-233537) and E. Dissimilis cm. Percentage of body weight composed of (U.S.N.M. Cato Nos. 233538 and 233539). water (% Pbw) was calculated by the folIowing fo rmula: TABLE 1

Summaryof collections from northern Boca % Pbw = Wet Weight - Dry Weight x 100 Raton, Florida, from October 28 to November Wet Weight 12, 1984. N = To tal number of organisms; % = Percentage of relative abundance; CW = Carapace (% width in cm (mean values 1 standard deviation); Percentage of body water lost P 1) due to ± desiccation at time of death was calculated by and Range (CW) = Range of carapace width (cm) the folIowing formula: E. depressus E. dissimilis % PI = Wet Weight - Weight at Death x 100 N 98 39 % 72 28 Wet Weight - Dry Weight

1.07 0.25 0.94 ± 0. 16 CW ± The difference between the initial wet weight Range (CW) 0.65 - 1 .80 0.75 - 1 .30 and the final dry weight was considered to be the water content of the . The percent of Laboratory maintenance: Both species of this water content lost at each time interval was Eurypanopeus were maintained separately in calculated, and mean values were plotted for community tanks (19.5 cm diameter). Each both species. tank contained dead oyster shelIs for shelter and 600 mI of 34.00/1000 sea water. The water was aerated continuousIy and changed every 24 Salinity tolerance: Salinity tolerance of both hours to prevent the waste build-up. No more species of Eucypanopeus were measured in O, 5, than 50 crabs were maintained together in a 17, 34, 45, and 75.00/ 1000 at room temperatu­ single tank at any time. During this study, the re (19.0 - 21.0 C). The activity of each crab was water temperature range in the laboratory was assessed as folIows: freely moving and active, 2 15.5 - 22.5 oC, with an average of 20.0 ± 1.5 points, lethargic and failing to move after gentle oC; room temperature range was 15.0 - 22.0 prodding, 1 point; dead, O points (Shumway, oC, with an average of 20.0± 1.00C. Crabs were 1983). GARCES: Behavior of E. depressus and E. dissimilis 175

Temperature tolerance: Temperature tole­ TABLE 2 rances of both species of Eurypanopeus were Desiccation tolerance. % water loss is amount 01 wigh t determined by observing the behavior while in­ lost due to desiccation. Survival time is measured from creasing or decreasing the water temperature. introduction into desiccator until death. Intervals ol time Five crabs of each species were placed in a glass needed lor successive wighingsare not included. Values are means 1 standard deviation dish (7.8 cm in diameter) with equal volumes ± (200 mI) of 34.00/1000. The dish with the crabs N Mean Size Mean % Mean Survival was placed inside a bigger dish (15.0 cm in dia­ dry Water Loss Time (min.) meter), and hot or cold water was poured' at (g wt.) intervals into onIy the bigger dish. The tempera­ E. depressus 10 0.16 28.9 ± 10.0 508.8 ± 28.3 ture was meassured with a scale thermometer (O - 50 oC) placed inside the smaller dish with the E. dissimilis 8 0.15 20.5 ± 6.0 262.7 ± 32.4 crabs. In the decreasing temperature experimen­ ts the water temperature was lowered gradually TABLE 3 from 19.0 Oc to 9.0 oC in 1 hour. In the increa­ sing temperature experiments the water temp­ Cumulative water loss percentage. (*) Relers to erature was gradua11y raised from 19.0 oC to beginning 01 stress, characterized by lack 01 39.0 oC in 2 hours. The water temperature was movements and contraction 01 all the walking legs and chelae towards the body raised or lowered until death occured using two crabs per species under similar conditions. Time Cumulative Cumulative Al experiments were carried out in duplicate. (min.) Water Loss (% ) Water Loss (% ) E. depressus E. dissimilis Dominance and coexistence: In the domi­ 60 4 11 nance and coexistence experiments different 120 9 14* sizes, sexes and species combinations were pla­ 180 13 22 ced together in a glass dish (7.8 cm in diameter) 240 17* 25 with 200 mI of 34.00/1000, and their behavior) 300 22 28 then observed and recorded. All experiments 360 23 420 27 were carried out at room temperature (19.0 - 480 28 o 21 O C) and lasted 30 mino Three combina­ 540 32 tions were used: 1. E. depressus - E. depressus interactions; 2. E. dissimilis - E. dissimilis inte­ min.) and E. dissimilis (263 min.), with E. de­ raction; and 3 . E. depressus - E. dissimilis inte­ pressus surviving over 1 1/2 times as lo ng as E. raction. dissimilis (Jable 2). The mean percentage of water lo ss was similar with E. depressus sho ­ Individual behavior differences: Individual wing a mean value of 29.0%, and E. dissimilis behavior differences within both species, were showing a mean value of 21.0% (Table 2). Ho­ noted and recorded throughout the experimen­ wever, the cumulative percentage of water loss tation periodo During experimentation the con­ by both species was different. In E. depressus trols were used for behavioral observation; a1so, 4.0% of water loss vas achieved in the first occasional periods of extra observation were ca­ hour, while E. dissimilis lo st 11.0% in the same rried out (Le., behavior on sandy bottom dish). period; by the second hour, E. depressus had In this experiment 5 crabs of both species of lo st 9.0% of water, while E. dissimilis had lost Eurypanopeus were placed in a glass dish (7.5 14.0%, falling under a stress condition (Table cm in diameter) with a small layer of beach 3). The stress condition was observed on E. de­ sand (1.5 cm in width) on the bottom, and 200 pressus when it lost 17.0% of water after 4 mI of 34.00/ 1000. AII experiments were carried hours of desiccation. The stress condition was out at room temperature (19.0 OC), la sted 30 characterized by lack of movements and con­ min., and were done in quintuplicate. traction of a11 the walking legs and chelae to­ ward the body. 80th species began with diffe­ RESULT AND DISCUSSION rent percentages of body weight due to water (57.0% in E. dissimilis, and 64.0% inE. depres­ Desiccation: Death by desiccation was subs­ sus), and had lost slightly different amounts of tantially different between E. depressus (509 water at the time of death (27.0% in E. dissimi- 176 REVISTA DE BIOLOGIA TROP IC AL

TABLE 4 E. depressus • Parameters used in desiccation E. dissimilis toleran ce experiments. 10 •

N = Numbers o[crabs; CW = Carapace width in cm; Range (CW) = Range o[carapace width (cm);

Pbw = Percentage o[total body weight 9

due to water; PI = Percentage o[ total body water loss at time o[ death. Allvalues except range are means ± 1 standard deviation 8

E. depressus E. dissimilis ,....., 7 ...; N 10 8 S ::t: E-< 6 CW 1.22 t 0.19 1.08 ± 0.12 « � Range (CW) 0.85 - 1.35 1.00 - 1.25 Q O 5 Pbw 64.30 t 1.54 56.90 t 1. 64 E-< PI 30.80 1.73 26.60 0.74 � ± t al E-< 4

:3 55 I I SURVIV AL TIME 2 50 FINAL % IWATER LOSS 45

• E. depressus 40 .5 .1 .15 .2 .25 • E. dissimilis � DRY WEIGHT (g.). tIl tIl 35 Fig. 2 Scatter diagram of dry weight (g) against time O ....;¡ to death (hours). � � E-< 30 « � lis, and 31 .0% in E. depressus) (Table 4). These � 25 three' percentages are apparently not a function :> ¡:: of size beca use the entire range of carapace « ....;¡ widths remained constant with only a slight ;:¡ 20 standard deviation (1.1 ± 0. 12 cm in E. dissimi­ and 1.2± 0.19 cm in (T able U lis, E. depressus) 4). � 15 E. depressus showed a greater resistance to des­ iccation than E. dissimilis. with a greater survi­ val time, and a slightly higher value for fmal 10 percentage of water loss (F igure 1). This resist­ ance to desiccation was true although the mean 5 dry weights (g) were very similar (0.16 g in E. depressus, and 0. 15 g in E. dissimilis) (T able 2). When time to death was plotted against dry 120 240 360 480 600 weight (g) a clear separation on the scatter dia­ gram was obtained for both species (Figure 2). CUMULATIVE TIME (min.) Both species of Eurypanopeus studied seem to Fig. 1. Desiccation rates for the two Xanthid crab spe­ be sensitive to desiccation, having lost about cíes. Mean values ± 1 standa rd error for survival time 27.0 - 31 .0% of body water at time of death. and final % wate r loss are indicated for each spec íes. Yo ung (1978), using identical methods, found a GARCES: Beh llvior of E. depressus lIn d E. dissimilis 177

• A B �.depressus • • 10 • E.dissimilis 8 � 6

4

2

O

W a:: 10 - O ..�------���-4�. U 8 �.------.�------.. __-4 en

W 6 U Z 4 « a:: 2 W 3 ....J 4 0 g O 0/00 17 /00

10

8

6

4

2

O 12345678 HOURS

TIME Fig. 3 Mean toleranee seo res in 0, 5, 17, 34, 45, and 75.00/1000. Toleranee seored as 2 points for each acti ve anim al, 1 point for eaeh lethargic, and O for eaeh dead animal. 178 REVISTA DE BIOLOGIA TROPICAL

50.3% water loss at death in the intertidal her­ mit crab Clibanarius vittatus (Bosc) with shell 45 removed, a value larger than the one obtained '41 (106) for both species of Eurypanopeus. Grant and 40 I I I I McDonald (1979), using similar methods, found a 30. 1 % water loss at death for intert idal popu­ 35 35(95) lations of E. depressus. and 32 .0% for subtidal (86l30 30 populations, a value very close to the one fo und Uill 28(82) here for E. depressus. Their experiments suggest 25 that within the intertidal zone, low desiccation (73)23 E 21 (70) tolerance may be indicative of the greater im ­ (6 6) 19 � 20 portan ce of the microhabitat for a given spe ­ cies, and this was particularly important to E. 15 (55) 13 l3 dissimilis. It is speculated that without the pro­ 10 tection of the substrate (oyster shell beds) from (46) 8 I I I rrrn desiccation extremes, neither species of Eurypa­ 5 I I I I I nopeus could live intertidally . �.depresus o �.dissimilis Sa linity : There were no adverse effects on either species at 34. 00/1 000 (control) (Fig ure 3C) , and after 16 days they still were alive and ACTIVITY THERMOMETER (OC) healthy. The tolerance level diminished, while Fig. 4 "T hermogram " showing the best temperature reducing the salinity from control, at 17, 5, and range, upper and lower lethal limits, and optimal temperature. o F is shown in parentheses. 0. 00/1 000, in both species withE. dissimilissho­ wing a slightly lower level of tolerance than E. depressus (Figure 3D , 3E , and 3F). In increas­ showed normal activity was fo und to be be­ ing water salinity from control, both species tween 13.0 - 23.0 o C. The lethal temperature presented a reduced level of tolerance at 45 and limits for E. depressus were 30.0 oC and 8.0 75.00/1 000, with E. dissimilis showing a slightly oC. The best temperature range fo r E. dissimilis lower level of tolerance than depressus (Figu­ was between 21.0 - 35 .0 o C, with lethal tempe E. o o re 3A and 3B ). In general, E. depressus has the rature limits of 41.0 C and 13.0 C. It was greater resistance to salinity changes with high ­ found that depressus did best at 19.0 o C, E. o er tolerance to both salinity extremes (O and and E. dissimilis at 28.0 C. In general, E. de­ 75.00/1 000). Experimental results were consis­ pressus tolerated cooler temperatures much tent with past reports (Shumway 1983). Adults better than E. dissimilis. It is suggested that E. have been captured between 4.5 - 52.00/1 000 dissimilis was studied near their lower limits of (Rouse 1970; Williams 1984) Costlow and best temperature range. E. depressus is reported Bookhout (1961) reared E. depressus larvae to be found in a very wide temperature range , in a wide salinity range (12.5 -31.00/1 000) 16.0 - 32 .0 o C (Lyons, et al. 1971; Godcharles under laboratory conditions. Fo r E. dissimilis, and Jaap 1973). From the current experimen­ salinities of 5.00/1 000 seemd to be near their tal results, it is expected that E. depressus may lower limit of tolerance. For this reason it is be found at cooler temperatures than those re­ suggested that their limit is reached at a higher ported. salinity between 5 and 17. 00/1 000). Thus, they can be found in situ from there through Dominance and Coe xistence: E. depressus - 45.00/1 000. E. depressus interaction: Adult males stayed away from one another most of the time. When Tem pe rat ure : E. depressus showed a narrow­ encountering each other, usually the first crab er normal range of temperature (22.0 o C) that attacked do minated the other, causing it to which they can withstand without distress than move away , regardless of size . Adult males were E. dissimilis (28.0 OC) (Figure 4) , but Eurypan­ dominant over juveniles, but no signs of aggres­ opeus depressus showed a wider range toward sivenes were shown against ovigerous and non­ warmer temperatures (above 20 o C) . The best -ovigerous females. Ju veniles were aggressive temperature range in which E. depressus and usually the first that attacked dominated. CAReES: Behavior of E. depressus and E. dissimilis 179

TABLE S. • �.depressus A survey 01ethograms, based on laboratory observation. • E.dissimilis (*) Indicates elevation 01 the last two pairs 01 walking legs PENSACOLA

Ethograms Species showing pattern: Act Pattern E. depressus E. dissimilis

1. Body Postures 1. Normal yes yes 2. Rearing* no yes FORT II. Direct Movements PIERCE 1. Move toward yes yes 2. Move away yes yes BOCA RATO N 111. Chelipeds 1. Non-contact display yes yes , 2. Contact display yes yes O MILES 100 CAPE SABLE , ! FLAMINGO ISLAND '11¡ SCALE IV. Wa lking Legs � 1. Non-contact yes yes �";� yes yes ��.,.",,, 2. Contact ('push ing ') Fig. S. Known reports for Eurypanopeus depressus and Eurypanopeus dissimilis in Florida. Location of V. No Re sponse ('free ze ') no yes the Boca Raton collection site is also shown.

E. dissimilis - E. dissimilis interaction: Ovig­ jumping over other crabs when irritated. E. dis­ erous females are dominant over non-ovigerous similis, in general, showed less aggressive beha­ females and juveniles of both sexes. Adult ma­ vior. When disturbed they displayed a typical les showed no aggressiveness toward females. stress position, placing all their walking legs and E. depressus - E. dissimilis interaction: Lar­ both chelae c10sely toward the body, forming ger adult males of E. depressus were dominant the body into a retracted configuration. If dis­ over smaller adult and juvenile E. dissimilis ma­ turbed by an approaching aggressive crab, E. les and ovigerous and non-ovigerous E. dissimi­ dissimilis retreated against the wall of the dish lis females. However, larger E. dissimilis oviger­ and showed a rearing position, raising the first ous females were dominant over smaller juveni­ two pairs of walking legs and holding that pos­ les and adult E. depressus males. If equal in ture for a time. According to Wamer (1971), size, E. depressus females were dominant over this signal cornrnunicates the threat of an at­ E. dissimilis males. There was aggressive beha­ tack. vior between males and females of different species. Ultimately, one caused the other to Sandy bottom dish: E. depressus either sta­ move away. with E. depressus being the more yed in the same place without movement, or dominant. Although encounters are possible in moved carefully, staying aboye the sand. On the nature because of the same habitat, it is suggest­ other hand, E. dissimilis either moved actively ed that interpecific mating is avoided. In either and fed on small partic1e s for a few minutes and case, males and females of each species showed then began burrowing, or it began burrowing no signs of acceptance of a foreign species in its immediate1y. The burrowing behavior consisted territory. A survey of the ethograms observed of making a hole with the walking legs first, for both species is presented in Table 5. then introducing its body backwards into the sand, and while the sand was thrown away with Individual behavior differences: Aggressi­ both chelae the body of the crab was pushed veness: E. depressus in general showed a greater into the sand. After 5 minutes 1/3 of the cara­ aggressiveness. When disturbed this species ope­ pace was visible and after 15 minutes, just 1/4. ned wide both chelae while raising the anterior This burrowing behavior has not been reported part of the body to a 450 angle. Adult males of for any xanthid species and may be a factor E. depressus made jerky movements with the affecting E. dissimilis distribution in certain entire body while waving their big chelae and available areas. 180 REVISTA DE BlOLOGIA TROPICAL

Feeding: Eurypanopeus depressus was seen ACKNOWLEDGEMENTS feeding at any time between 12:30 p.m. and 11:00 p.m., showing more activity at night. E. 1 am particularly indebted to the following dissimilis was found feeding in two periods: persons who contributed to the success of this between 10 - 11 a.m. and 10 - 11 p.m., when investigation: R.B. Manning of the National the temperature was higher (21.0 - 22.5 OC). E. Museum (United States) for species verification; depressus was observed to feed on suitable size G. Alex Marsh for providing literature and detritus particles on the bottom of the cornmu­ equipment; Agustin Bethancourt for transpor­ nity tank, on fish pellets, and on eggs of ovige­ tation; Beckie Dayton for access to the collec­ rous E. depressus and E. dissmilis females.E. tion site; George Caspelich for equipment and dissimilis fed on the smallest detritus particles access to laboratory; Daniel F. Austin, Chryseis and eggs of ovigerous E. depressus females. The Blake, and Olubayi Olubayi for revision of the slight differences in food supplies encountered text and cornments; and to F AU Graphics De­ suggests a spatial partition of their microhabitat partment personnel for all figures and table in terms of food supplies and space. Thus, this artwork. enables them to coexist in the same area.

RESUMEN CONCLUSIONS Una serie de experimentos y observaciones Based on all the information obtained from fueron hechas en dos especies de cangrejos this research and all other sources, E. depressus Xanthidae. Se encontraron diferencias en su re­ and E. dissimilis are maintained as different spe­ sistencia a la desecación, tolerancia a diferentes cies. The primary differences being the follow·, salinidades y temperaturas, dominancia y coe­ ing: xistencia, agresividad, alimentación, y respuesta a un nuevo habitat. Los resultados comprueban 1. Morphological: Carapace tooth shape el previo esquema de su clasificación que consi­ (first and second teeth fusion), lobiforme in E. dera a ambas como especies distintas. Se con­ depressus and dentiforme in E. dissimilis; color cluye que Eurypanopeus depressus y Eurypa­ of propodal fmger, not continued onto palm in nopeus dissimilis estan relacionadas simpátri­ E. depressus and color spreads upward in E. camente y se mantienen separadas por diferen­ dissimilis; red spot present on inner surface of cias en comportamiento. third macilliped ischium, oval and bigger (2/3 of structure) in E. depressus and round and smaller (1/3) in E. dissimilis; male abdominal REFERENCES segments (third and fourth segments), fused in E. depressus and not fused in E. dissimilis; and Crane, J. 1975. Fiddler Crabs of the World. O cypo didae: Genus Uc a. Princeton University chelae height ratio (minor to major manus), Press, N.J. 736 p. higher ratíos (2/3) on E. depressus than in E. dissimilis (1/2). Costlow, 1.0. & C.G. Bookhout. 1961.The larval devel ­ opment of Eurypanopeus depressus (Smith) under 2. Distributional: E. depressus is a mostly laboratory conditions. Crustaceana 2: 6-15. northem species, while E. dissimilis prefers Forward, R.B , Jr. 1985. Behavioral responses of larvae warmer localities. of the crab Rhithropanopeus harrisii (Brachyura: Xanthidae) during vertical migration. Mar. Bio l. 3. 8ehavioral: Differences were found in 90 : 9-18. desiccation, salinities and temperature toler­ Godcharles, M.F.&W. C. Jaap. 1973. Fauna and flora ances; dominan ce and coexistence; aggres­ hydraulic clam dredge collections from Floridain siveness, feeding and response to a new habitat west and southeast coasts. Fla. Dep. Nat. Res. Mar. (sandy bottom dish). Res. Lab. Spec. Rep., No. 40. 89 p. From all this information it can be con­ Grant, H.J. McDonald. 1979. Desiccation toler­ cluded that E. depressus and E. dissimilis are 1. & ance of Eurypanopeus depressus (Smith) (Decapo­ two distinct species that live sympatrically on da: Xanthidae) and the exploitation of microhabi­ the locality studied. tat. Estuaries 2: 172-177. CARCES: Behavior of E. depressus and E. dissimitis 181

Hazlett. B.A. 1976 . Agonistic behavior of two symp­ Savage, T. 1971. Mating of the stone crab, Menippe atric species of xanthid crabs, Leptodius floridanus mercenaria (Say) (Decapoda, Brachyura). Crusta­ and Hexapanopeus angustifrons. Mar. Behav. Physi- ceana 20: 315-316. 01. 4: 107-1 19. Sulkin, S.D., VI .F. Van Heukelem & P.A. Kelly. 1983. Hines, A.H. 1982. Allometric constraints and variables Behavioral basis of depth regulation in hatching of reproductive effort in Brachyuran crabs. Mar. and postlarval stages of the mud crab Eurypan­ Biol. 69: 309-320. op eus depressus. Mar. Ecol. Prog. Ser. 11 : 157-164.

Kelly, P.A., S.D. Sulkin & W.F. Van Heukelem. 1980. Shumaway, S.E. 1983. Oxygen consumption and salin ­ Response of stage I zo eae of two crabs species to ity toleran ce in four Bra zilian crabs. Crustaceana gravity and thermal gradients. Am. Zool. 20: 780. 44: 76-82. Lyons, W.G., S.P. Cobb, D.K. Camp, 1.A. Mountain, T. Savage, L. Lyons & E.A. Joyce, Jr. 1971. Pre­ Swart z, R.C. 1976. Agonistic and sexual behavior of liminary inventory of marine invertebrates collect­ the xanthid crab, Neopanope sayi. Chesapeake Sci. ed near the electrical generating plant, Crystal Ri­ 17: 24-34. ver, Florida, in 1969. Fla. Dep. Nat. Res. Mar. Res. Lab. Prof. Papo Ser., No. 14. 45 p. Turner, K. T. Alyerla. 1980. Electrophoretic varia­ tion in &sympatric mud crabs from North Inlet. Mirkes, D.Z., W.B. Vernerg, and P.J. DeCoursey. 1978. South Carolina. Biol. Bull. 1959: 418427. Effects of cadmium and mercury on the behavioral responses and development of Eurypanopeus de­ Warner, G.F. 1977. The Biology of Crabs. Elek Scien­ pressus larvae. Mar. Biol. 47: 143 147. ce, London. 202 p. Rathbun, M.J . 1930. The cancroid crabs of America of Williams, A.B. 1984. Shrimps, Lobsters, and Crabs of the families Euryalidae, Portunidae, Atelecyclidae, the Atlantic Coast of the Eastern United Sta tes, Cancridae and Xanthidae. Bull. U.S. Nat. Mus., No. Maine, to Florida. Smith. Inst. Press, Washington, 152.609 p. D.C. 550 p.

Rouse� W.L. 1970. Littoral Crustacea from Southwest Young, A.M. 1978. Desiccation toleran ces for three Florida. Q. 1. Fla. Acad. Sci. 32: 127-152. hermit crabs species Clibanarius vittatus (Bosc), Pa­ gurus pollicaris Say and P. longicarpus Say (Deca ­ Salmon, M. 1967. Coastal distribution, display and poda, Anomura) in the North Inlet Estuary, South sound production by Florida fiddler crabs (genus Carolina, U.S.A. Estuarine and Coastal Marine Uca). Anim. Behav. 15: 449459. Science 6: 117-122.