Contributions to Zoology, 66 (2) 65-102 (1996) SPB Academic Publishing bv, Amsterdam New hypogean cyclopoid copepods (Crustacea) from the Yucatán Peninsula, Mexico Frank Fiers Janet W. Reid Thomas M. Iliffe & Eduardo Suárez-Morales 1 Invertebrate Section, Royal Belgian Institute of Natural Sciences, Vautierstraat 29, B-1000 Brussels, Bel- 2 gium', Department of Invertebrate Zoology, MRC-163, National Museum ofNatural History, Smithsonian 3 Institution, Washington DC 20560, U.S.A.; Department of Marine Biology, Texas A&M University, 4 Galveston, Texas 77553-1675, U.S.A.; ECOSUR, El Colegio de la Frontera Sur - Unidad Chetumal, Apdo Postal 424, Chetumal, Q. Roo 77000, Mexico Keywords: Diacyclops, Mesocyclops, Copepoda, Cyclopoida, biogeography, evolution, hypogean, karst, species-flock, taxonomy, Mexico Abstract del género Diacyclops ocurrenraramente en las regiones tropi- cales los dos descritos el tercer y Diacyclops aquí son segundo y del en México. La Four unknown of representantes género registrados especie previously hypogean species cyclopoid cope- ha encontrado de béntica D. se en un grande cuerpo agua pods were collected in cenotes and wells of the Yucatán Penin- puuc subterránea (cenote). chakan se ha encontrado sólo Mexico. chakan and D. differ Diacyclops sula, Diacyclops sp. n. puuc sp. n. estes de subterrá- from their in excepcionalmente en cuerpos grandes aguas congeners combining 3-segmented swimming es frecuente abundante en and neas, pero y pozos. legs, 11-segmented antennules, legs 1-4 endopodite seg- Las dos de M. chaci n. M. especies Mesocyclops, sp. y yutsil ment 2 all with 2 setae. Species of Diacyclops rarely occur in la béntica M. reidae sp. n. son muy semejantes a especie tropical regions, and the Diacyclops described here are only the Petkovski, están modificadas la vida hipógea con la second and third species recorded from Mexico. The benthic pero para de ornamentaciones en el cuerpo y el D. found in the reservoir of pérdida parcial adelgaza- puuc was large underground a miento de las natatorias bucales. chakan encountered in such patas y partes Mesocyclops cenote. Diacyclops was large open chaci vive in creviculares las de sp. n. lugares como paredes subterranean water basins, but more frequently and abundantly cavernas n. se carac- in wells. pozos y pequeñas. Mesocyclops yutsil sp. teriza el más de las es The M. chaci and M. por pronunciado adelgazamiento patas, two Mesocyclops species, sp. n. yutsil vive de subterráneas. planctónica y en cuerpos grandes aguas sp. n., most closely resemble their epigean benthic congener M. Los apéndices extremadamente adelgazados distinguen las dos reidae Petkovski, but are modified by loss of some body orna- especies de los demás Mesocyclops son similares a los de la ment and attenuation of swimming legs and mouthparts. y delamarei Lescher-Moutoué. Las chaci crevicular and especie hipógea Kieferiella Mesocyclops sp. n. occupies spaces (wells de consideradas small The second M. with tres especies Mesocyclops son como un parti- caverns). species, yutsil sp. n., more cular ha radiado dentro de conjunto que como especialistas un pronounced attenuation of legs, has a planktonic life in large ambiente altamente dinámico. subterranean volumes. The attenuated geomorfológico water extremely appen- dages ofboth species distinguish them from all other Mesocy- clops, and resemble those of the hypogean Kieferiella delama- rei Lescher-Moutoué. These three species are considered as a Introduction species-flock which have radiated as specialists within a highly dynamic geomorphological environment. Collections of crustaceans from cenotes, wells and caves in the States of Yucatán and Quintana Roo, Resumen Mexico, contained four previously unknown cy- clopine copepods, two Diacyclops and two Meso- Se recolectaron, en cenotes de la Peninsula Yucatán, y pozos cyclops. These are described and their possible México, cuatro especies de copépodos ciclopoides hipógeos systematic affinities discussed by F. Fiers and J.W. desconocidos. chakan D. previamente Diacyclops sp. n. y puuc Reid. We describe the geological and ecological difieren de al combinar natatorias sp. n. sus congéneres patas conditions that have contributed to the tri anténulas de 11 2 el might segmentadas, segmentos y setas en se- evolution of these gundo segmento del endopodito de las patas 1-4. Las especies hypogean species. Downloaded from Brill.com10/08/2021 06:20:44AM via free access 66 F. Fiers et al. - New copepods from Mexico Methods Type-specifications. - Holotype, dissected 9, mounted on 3 slides, labeled COP 3863a,b, c; allotype CT, dissected, mounted on 3 slides, COP 3864a, b, c; dissected paratypes: 1 Ç COP Some specimens, collected by T.M. Iliffe and colleagues, were , 3865a, b, c; 1 9, COP 3866a; 1 cr, COP 3867a,b, c; ethanol- taken with a plankton net from the surface to as deep as 30 m in 69 COP and preserved paratypes: 9 9,1 CT, 3868, sample several cenotes. Although the water in most cenotes was"fresh" filtrate (still containing specimens), COP 3920; 24 9 9, (0-2%o) at those depths, most samples contained copepods of many 1 5 USNM 274313. CT, copepodids, both continental freshwater and marine affinities. The latter of Type-locality: man-made well (pozo), located onproperty were sent to appropriate specialists for determination and "Rancho Antonio Kanah" along Kinchil - Celestún road description. (Yucatán), approximately 23 km from Kinchil, and 1 km from Crustaceans collected by F. Fiers and colleagues came from road. Coordinates (estimated): 20°53'30"N, 90°07'09"W. Well of habitats, man-made wells, a wide variety including open fine has diameter of 1 m, depth 4 m. Bottom sediments are cenotes and nearly closed aguadas (karstic caverns with a small brilliant white sand. At time of sampling, well contained 1 m of to large water pool). All samples were taken with a plankton net water, and was covered with iron lid. Sample MEX 93-88, leg. that was repeatedly lowered in the water column and rapidly - J. Vargas, M. Herrera, and F. Fiers, 8 November 1993. Addi- withdrawn to create a current sweeping the walls of the water tional fauna: 1 9 V Macrocyclops reservoirs. copepod copepodid stage albidus s. str., COP 3869a, b, and crustacean the F. and his assistants collected (Jurine, 1820) c; In same way, Dr. Moravec fauna cenotensis (Creaser, chaci in closed man-made well Antromysis 1936), Typhlatya pear- Mesocyclops sp. n. a near sei Creaser, 1936;ostracodes; 1 stygobiotic amphipod. Cheuman, Yucatán, and used this species succesfully as the experimental intermediate host of two nematode species Additional material. - parasitic in fish (F. Moravec, in litt, to F. Fiers). (1) Chen-Ha Cenote, Chochóla (Yucatán), west side of main Specimens were fixed in formalin and transferred to 70-75% highway midway between Chochóla and Maxcanu. Coordi- ethanol for long-term storage. For taxonomie examination, they nates: 20°34'10"N, 89°52'30"W. Commercially operated fresh- were transferred in stages to glycerine and examined either in of 95 water swimming cenote consisting open pool m long by glycerine (J.W. Reid and F. Fiers) or in lactic acid (J.W. Reid). 64 m wide, with large underwater cavern entrance extending Permanent mounts were made in polyvinyl lactophenol (PVL) 25 m maximum in 24 in little chlorazol black added in horizontally; depth open pool m, cavern with a E (J.W. Reid) or glycerine mesh 30 m; bottom primarily mud. Sample taken with 93 |im with sealed coverglasses (F. Fiers). J.W. Reid made most plankton net at 18-28 m depths in cavern. Sample 93-043, leg. drawings at magnifications of600x and confirmed the details at T.M. Iliffe, 6 July 1993: 1 9, dissected on slide in PVL, USNM lOOOx using an oil immersion lens on a Wild M30 microscope 259839. - Additional copepod fauna: Mastigodiaptomus albu- fitted with a drawing tube. F. Fiers made his drawings at 1250 x 1 9 4 copepodids, USNM querquensis (Herrick, 1895), , using an oil immersion lens on a Leitz Dialux 20, equipped with 278028; albidus s. Str., 1 CT, USNM 278030; tube. Undissected in 70% Macrocyclops a drawing specimens were preserved 1 USNM 278029; Thermocyclops ethanol. Microcyclops sp., copepodid, and USNM and inversus Kiefer, 1936, 119 9 CTCT, 278031; The specimens were deposited in the collections ofthe De- crustacean fauna: amphipods, thermosbaenaceans. partment of Invertebrate Zoology, United States National Mu- (2) Mucuyché Cenote, located within the ruins ofa hacienda in seum of Natural History, Smithsonian Institution (USNM) and the village of Mucuyché (Yucatán). Coordinates: 20°37'23"N, in the Invertebrate Collection of the Royal Belgian Institute of 89°36'18"W. From the crescentic sinkhole entrance, a flight of Natural Sciences, Brussels (COP). to steps leads down a breakdown slope a 30 m long by 10 m wide, gravel and rock floored freshwater pool. On the far side of the about 8 hole pool at m water depth, a narrow opens onto a Descriptive part 50 m long, 10 m wide breakdown chamber that angles diago- vertical breakdown nally down to 30 m depth. At this point, a Burmeister, 1834 Family Cyclopidae shaft ascends to 15 m depth before choking off. Sample taken chamber. Subfamily Cyclopinae Dana, 1853, emend. Kiefer, with plankton net at 20-30 m depth in breakdown 1927 Sample 93-045, leg. T.M. Iliffe, 9 July 1993: 1 cr, USNM 259840, 1 copepodid, USNM 259842. - Other crustacean Genus Diacyclops Kiefer, 1927 fauna: mysids (Antromysis cenotensis), thermosbaenaceans, and amphipods, isopods [Creaseriella anops (Creaser, 1936)]. Diacyclops chakan Fiers & Reid, sp. n. (3) Yuncu Cenote, located 1.5 km west ofYuncu (Yucatán), on (Figs. 1-7) east side of abandoned railroad right-of-way running north to south. Coordinates: 20°34'51"N, 89°36'46"W. Vertical pit en- - Suárez-Morales 1996: 7 diameter and 10 Synonymy. Diacyclops sp. A, et al., trance, m m deep; a freshwater, U-shaped 27-30.