Open JERE Wilson Wesley Lazaro

The Pennsylvania State University

The Graduate School

College of Agricultural Sciences

SNAIL-EATING FISHES OF LAKE MALAŵI: (1) AGE AND GROWTH OF

TREMATOCRANUS PLACODON REGAN; (2) SYSTEMATICS OF CICHLID

GENUS MYLOCHROMIS REGAN

A Dissertation in Wildlife and Fisheries Science by

Wilson Wesley Lazaro Jere

Submitted in Partial Fulfillment of the Requirements for the Degree of

Doctor of Philosophy

August 2010

The dissertation of Wilson Wesley Lazaro Jere was reviewed and approved* by the following:

Jay R. Stauffer, Jr. Distinguished Professor of Ichthyology Associate Director of Graduate Studies Dissertation Adviser Chair of Committee

C. Paola Ferreri Associate Professor of Fisheries Management

Walter M. Tzilkowski Associate Professor of Wildlife Science

Timothy Ryan Associate Professor of Anthropology

*Signatures are on file in the Graduate School

Abstract

A study was conducted to determine the growth of the facultative molluscivore,

Trematocranus placodon Regan and describe new species of the cichlid genus

Mylochromis Regan from Lake Malaŵi. The results showed that there was significant interaction (p = 0.0180) between the sex of fish and the number of snails consumed on the growth rate of T. placodon. Both males and females had higher growth rate when they consumed more snails but males grew faster than females. Eight new species of the genus

Mylochromis have also been described.

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TABLE OF CONTENTS

List of Tables ...... vi

List of Figures ...... viii

Acknowledgements ...... xiii

Chapter 1. General introduction ...... 1

Chapter 2: Age and growth of Trematocranus placodon Regan ...... 4

Introduction ...... 4

Methodology ...... 5

1. Collection of fish specimen ...... 5

2. Otolith preparation ...... 6

3. Validation of daily rings and verification ...... 7

4. Storage of Fish and Otolith specimen ...... 8

5. Data collection and analysis ...... 8

Results and discussions ...... 9

1. Stomach analyses of Trematocranus placodon ...... 9

2. Using the sagittal otolith in determining growth in T. placodon ...... 9

3. Validation of daily rings and verification of counts in T. placodon ...... 10

4. Converting age daily increment counts to age estimates ...... 11

5. Growth curves and relationship of growth rate of T. placodon to site of collection, sex

and number of snails consumed ...... 12

Conclusion and recommendations ...... 18

Chapter 3: Systematics of the cichlid genus Mylochromis, Regan ...... 19

Introduction ...... 19

Taxonomic Analysis: Mylochromis Regan ...... 22

Methodology ...... 22

A. Described Species ...... 33

B. New Species ...... 118

General discussion on systematic of the genus Mylochromis ...... 199

References ...... 202

List of Tables

Table 1. Number of snails by species in the stomach contents of fish...... 13

Table 2. Validation of daily rings in T. placodon (N = 6) and verification of daily increments counts by two readers A and B...... 14

Table 3. Growth rate (mm/day) of males and females of T. placodon collected from Yofu Bay and

Crocodile Bay, Lake Malaŵi using estimated sagittal otolith daily increments ...... 15

Table 4. Regression analysis of the relationships of sex, number of snails consumed and their interaction on growth rate (mm/day) of T. placodon (N = 20 fish)...... 16

Table 5. Described species of the genus Mylochromis that were examined ...... 24

Table 6. Undescribed population of the genus Mylochromis from the Pennsylvania State

University fish museum...... 27

Table 7. The morphometric and meristic measurements that were taken from each fish specimen to be used in the sheared principal componentss analysis...... 31

Table 8. Morphometric and meristic values of Mylochromis anaphyrmus (n = 1), Mylochromis balteatus (n = 3) and Mylochromis chikopae (n = 23) ...... 50

Table 9. Morphometric and meristic values of Mylochromis ensatus (n = 10), Mylochromis epicholiaris (n = 2) and Mylochromis ericotaenia (n = 2) ...... 60

Table 10. Morphometric and meristic values of Mylochromis formosus (n = 2), Mylochromis gracilis (n = 3) and Mylochromis guentheri (n = 1) ...... 71

Table 11. Morphometric and meristic values of Mylochromis incola (n = 9), Mylochromis labidodon (n = 4) and Mylochromis lateristriga (n = 16) ...... 81

Table 12. Morphometric and meristic values of Mylochromis melanonotus (n = 1), Mylochromis melanotaenia (n = 3) and Mylochromis mola (n = 3) ...... 94

Table 13. Morphometric and meristic values of Mylochromis mollis (n = 1), Mylochromis obtusus

(n = 1) and Mylochromis semipalatus (n = 2) ...... 103

Table 14. Morphometric and meristic values of Mylochromis sphaerodon (n = 2), Mylochromis spilostichus (n = 1) and Mylochromis subocularis (n = 2) ...... 115

Table 15. Morphometric and meristic values of Mylochromis boadzului (n = 9) ...... 125

Table 16. Morphometric and meristic values of Mylochromis lapararhabdos (n = 2) ...... 132

Table 17. Morphometric and meristic values of Mylochromis lithoschalis (n = 12) ...... 140

Table 18. Morphometric and meristic values of Mylochromis lupingai (n = 4) ...... 148

Table 19. Analysis of variance for the PCA scores, which formed the minimum polygon clusters for the morphometric (SHRD_PC2) and meristic (PCA1) data for M. mesembrinos and M. notos.

...... 158

Table 20. Morphometric and meristic values of Mylochromis mesembrinos (n = 17) ...... 162

Table 21. Analysis of variance for the PCA scores, which formed the minimum polygon clusters for the morphometric (SHRD_PC2) and meristic (PCA1) data for M. mesembrinos and M. notos.

...... 170

Table 22. Morphometric and meristic values of Mylochromis notos (n = 6) ...... 171

Table 23. Morphometric and meristic values of Mylochromis rhabdos (n = 10) ...... 181

Table 24. Analysis of variance for the PCA scores, which formed the minimum polygon clusters for the morphometric (SHRD_PC2) and meristic (PCA1) data for M. strombodaptes and M. lateristriga...... 190

Table 25. Morphometric and meristic values of Mylochromis strombodaptes (n = 20) ...... 196

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List of Figures

Figure 1. Map of Lake Malaŵi showing the sampling sites: Likoma Island and Crocodile Rock .. 6

Figure 2. Scatterplot of length (mm) versus age (days) for females and males of T. placodon.

Open red circles: females from Yofu Bay; solid red circles: females from Crocodile Bay; open blue circles: males from Yofu Bay; and solid blue circles: males from Crocodile Bay...... 17

Figure 3. Truss diagram showing the morphometric measurements (white lines) and where meristic counts were taken (black lines)...... 29

Figure 4. Map of Lake Malaŵi showing the places where the undescribed specimens of the genus

Mylochromis were collected...... 30

Figure 5. Mylochromis lateristriga (GÜnther). BMNH 1921.9.6.150, 155 mm standard length. .. 33

Figure 6. Plot of sheared second principal componentss of morphometric data and first principal componentss of meristic data for M. lateristriga and M. balteatus...... 36

Figure 7. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lateristriga and M. incola...... 37

Figure 8. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lateristriga and M. melanotaenia...... 38

Figure 9. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lateristriga and M. mola...... 39

Figure 10. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lateristriga and M. sphaerodon...... 40

Figure 11. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lateristriga and M. subocularis...... 41

Figure 12. Mylochromis anaphyrmus. Source: www.malawicichlids.com...... 42

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Figure 13. Mylochromis balteatus (Trewavas). Lectotype. female, 125 mm standard length ...... 44

Figure 14. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. balteatus and M. lateristriga...... 46

Figure 15. Mylochromis chekopae (Turner and Howarth) ...... 47

Figure 16. Mylochromis ensatus (Turner and Howarth) ...... 53

Figure 17. Mylochromis epicholiaris (Trewavas). Lectotype, female, 170 mm standard length. . 55

Figure 18. Mylochromis ericotaenia (Regan). Lectotype, 59 mm standard length...... 57

Figure 19. Mylochromis formosus (Trewavas), Lectotype, 98 mm standard length...... 63

Figure 20. Mylochromis gracilis (Trewavas). Lectotype, male, 174 mm standard length...... 65

Figure 21. Mylochromis guentheri (Regan). Holotype, 153 mm standard length...... 68

Figure 22. Mylochromis incola (Trewavas). Lectotype, male, 97 mm standard length...... 74

Figure 23. Plot of sheared second principal componentss of morphometric data and first principal componentss of meristic data for M. incola and M. lateristriga...... 77

Figure 24. Mylochromis labidodon (Trewavas). Lectotype, female, 99 mm standard length...... 78

Figure 25. Mylochromis melanonotus (Regan)...... 84

Figure 26. Mylochromis melanotaenia (Regan), Lectotype, male, 143 mm standard length...... 86

Figure 27. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. melanotaenia and M. lateristriga...... 89

Figure 28. Mylochromis mola (Trewavas). Lectotype, male, 139 mm standard length...... 90

Figure 29. Plot of sheared second principal componentss of morphometric data and first principal componentss of meristic data for M. mola and M. lateristriga...... 93

Figure 30. Mylochromis mollis (Trewavas). Holotype, 133 mm standard length...... 97

Figure 31. Mylochromis obtusus (Trewavas). Holotype, 190 mm standard length...... 99

Figure 32. Mylochromis semipalatus (Trewavas). Lectotype, female, 141 mm standard length. 101

Figure 33. Mylochromis sphaerodon (Regan). Lectotype, 90 mm standard length...... 106

Figure 34. Plot of sheared second principal componentss of morphometric data and first principal componentss of meristic data for M. sphaerodon and M. lateristriga...... 109

Figure 35. Mylochromis spilostichus (Trewavas). Holotype, male, 181 mm standard length. .... 109

Figure 36. Mylochromis subocularis (GÜnther 1864)...... 111

Figure 37. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. subocularis and M. lateristriga...... 114

Figure 38. Holotype of Mylochromis boadzului...... 118

Figure 39. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. boadzului and M. balteatus...... 121

Figure 40. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. boadzului and M. mesembrinos...... 122

Figure 41. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. boadzului and M. strombodaptes...... 123

Figure 42. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. boadzului and M. lithoschalis...... 124

Figure 43. Holotype of Mylochromis lapararhabdos...... 128

Figure 44. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lapararhabdos and M. mesembrinos...... 131

Figure 45. Holotype of mylochromis lithoschalis...... 135

Figure 46. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lithoschalis and M. rhabdos...... 139

Figure 47. Holotype of Mylochromis lupingui...... 143

Figure 48. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lupingai and M. mesembrinos...... 147

Figure 49. Holotype of Mylochromis mesembrinos...... 151

Figure 50. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. balteatus...... 154

Figure 51. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. incola...... 155

Figure 52. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. lateristriga...... 156

Figure 53. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. notos...... 157

Figure 54. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. lupingai...... 159

Figure 55. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. rhabdos...... 160

Figure 56. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. lapararhabdos...... 161

Figure 57. Holotype of Mylochromis notos...... 165

Figure 58. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. notos and M. incola...... 168

Figure 59. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. notos and M. mesembrinos...... 169

Figure 60. Holotype of Mylochromis rhabdos...... 174

Figure 61. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. rhabdos and M. mesembrinos...... 177

Figure 62. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. rhabdos and M. strombodaptes...... 178

Figure 63. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. rhabdos and M. boadzului...... 179

Figure 64. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. rhabdos and M. lithoschalis...... 180

Figure 65. Holotype of Mylochromis strombodaptes...... 184

Figure 66. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. balteatus...... 187

Figure 67. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. incola...... 188

Figure 68. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. lateristriga...... 189

Figure 69. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. melanotaenia...... 191

Figure 70. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. sphaerodon...... 192

Figure 71. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. subocularis...... 193

Figure 72. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. boadzului...... 194

Figure 73. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. rhabdos...... 195

Figure 74. Mylcohromis lapararhabdos showing a continuous diagonal stripe...... 200

Figure 75. Mylochromis lithoschalis showing the blotchy and interrupted diagonal stripe...... 200

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Acknowledgements

I would like to that Dr. Jay R. Stauffer, Jr. who worked tirelessly to see me through this research. I would also like to thank Drs. C. Paola Ferreri, Walter Tzilkowski and Timothy Ryan, who accepted to serve on my dissertation committee and made valuable contribution to this work. Many thanks go to Dr. Ad Konings of Cichlid Press,

USA and Henry Madsen of DBL Centre for Health Research and Development who helped with fish species descriptions and snail identifications, respectively.

I owe a lot of gratitude to my labmates who helped me in many ways, particularly in procurement of research material. Mr. Rich Taylor and his wife, Kristin were always on hand to help me procure material whenever I wanted. Special thanks go to Mr.

Timothy Stecko who helped me with the initial design of the experiment and scanning of fish specimens.

I would like to thank the Pennsylvania State University fish museum for providing the undescribed Mylochromis fish specimens that I used in this research. I also thank the United States Museum of Natural History and the British Museum of Natural

History for providing specimens of described Mylochromis species.

I am greatly indebted to the Government of Malaŵi through Bunda College of

Agriculture, a constituent college of the University of Malaŵi, for granting me a three year study leave. Lastly, I would like to thank the Pennsylvania State University through the Agricultural International Programs and School of Forest Resources for the student assistantship and the National Science Foundation/National Institute of Health joint program in Ecology of Infectious Diseases (DEB-0224958) for supporting the research.

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Dedication

To all bilharzia patients.

xiv

Chapter 1. General introduction

Lake Malaŵi is the ninth largest freshwater lake in the world by surface area and the third largest by volume. It is approximately 600 km long and, at some locations, 80 km wide. It has a maximum depth of 700 meters. It covers a surface area of about 31,000 km2. It is bordered by three countries: Malaŵi, Tanzania, and Mozambique (Konings 2007). The estimated age of Lake

Malaŵi is 8.6 million years (Turner 2007). Lake Malaŵi harbors the most diverse ichthyofauna of any freshwater lake in the world, containing as many as 850 species (Konings 2007) with the majority of the species belonging to one family: Cichlidae.

The cichlids of the Great Lakes of Africa represent one of the most spectacular examples of speciation and adaptive radiation within a single vertebrate family, and many undescribed species are being discovered from newly explored areas (Stauffer and McKaye 2001). Most of the cichlid species in Lake Malaŵi are haplochromines while tilapiine cichlids have generally produced fewer species (Turner 2007). The majority of Lake Malaŵi‟s haplochromine cichlids are undescribed. The explosive radiation, recent origin, and high degree of endemism of cichlids have posed serious challenges for taxonomists to delimit species (Stauffer and McKaye 2001).

There is a continuing debate over which species concept is most appropriate for the classification of fishes. Biologists use the term „species‟ both as an evolutionary unit and as a category in the Linnaean hierarchy (Nelson 1999). Most biologists studying living organisms tend to favor species concepts that involve reproductive isolation or at least a clustering of genetic variation (Turner et al. 2001) and generally agree that species concepts should not conflict with the evolutionary history of organisms (Velasco 2008). The species definition for

Lake Malaŵi cichlids is based primarily on the evolutionary species concept (Kellogg and

Stauffer 1998, Pauers 2010 and Stauffer and McKaye 2001).

The evolutionary species concept states that a species is a single lineage of ancestral descendant populations or organisms which maintains its identity from other such lineages and has its own evolutionary tendencies and historical fate. This formulation represents an extremely important advantage over other species concepts, as it is nonoperational. It does not set out rigid criteria which one is supposed to use when evaluating the species-status of populations or organisms, which could limit the types of organisms it could distinguish as distinct species

(Pauers 1998). Given that the evolutionary species concept is nonoperational, the practicing taxonomist must use surrogate species concepts like biological or morphological species concepts with their operational definitions of species to distinguish species taxa (Stauffer and

McKaye 2001). Due to the lack of morphological differentiation and the inability of genetic data to distinguish cichlid species in Lake Malaŵi, a combination of genetic, morphological, and behavioral data should be used to describe new species (Stauffer et al. 2002).

The determination of the specific status of local taxa is critical for the development of programs both to conserve and utilize fishes for food, tourism, disease control, trade and scientific investigation (Kellogg and Stauffer 1998). Lake Malaŵi provides 70 % of animal protein in Malaŵian‟s diet. The major threats to Lake Malaŵi fish fauna are overfishing and exotic fish introduction (Reinthal 1993).

One group of fishes that has been heavily overfished is that of molluscivorous fishes that has resulted in a dramatic increase in the prevalence of snail hosts that harbor parasites that lead to schistosomiasis among the local residents and tourists (Stauffer et al. 2007). There is a need to identify and describe molluscivorous species and study their biology so as to introduce better

2 management strategies to them. This study was aimed at determining the growth of

Trematocranus placodon, a facultative molluscivore, and describing new species of the genus

Mylochromis.

Trematocranus placodon was chosen because it is a facultative molluscivore, which means that it can survive on diets other than snails. Pond experiments have shown that T. placodon reduced the snail population significantly in aquaculture setting (Chiotha et al. 1991).

The genus Mylochromis was chosen because some of its members (e.g. Mylochromis anaphyrmus and Mylochromis sphaerodon) are obligate molluscivore, which means that they require snails as their diet. Many populations belonging to this genus remain undescribed and before they can be effectively used in snail control programs, their specific status need to be resolved.

Chapter 2: Age and growth of Trematocranus placodon Regan

Introduction

Malaŵi has a high prevalence of infection with human schistosomes, which has been recognized for more than 80 years (Cullinan, 1945, Dye 1924 and Ransford 1948). Malaŵi is one of the countries where both urinary and intestinal schistosomes are endemic (Phiri et al. 1999).

Historically, transmission has occurred in swampy areas and backwaters adjacent to the shorelines of Lake Malaŵi where snail hosts, which transmit urinary schistosome, Schistosoma haematobium, are relatively abundant. From the mid-1980‟s, there has been a dramatic increase in snail populations in the open waters of Lake Malaŵi. It has been shown that overfishing of molluscivorous fishes was correlated to an increase in snails that act as intermediate hosts to urinary schistosomes (Stauffer et al. 1997). In recent years, there have been a lot of publications and travel warnings among tourists and resident expatriates about schistosomiasis infection in

Lake Malaŵi (Cooke et al. 1999, Corachan 2002, Jelineck et al. 1996, Madsen et al. 2004,

Moore and Doherty 2005, Nicolls et al. 2008 and Potasman et al. 1996).

Physical, chemical and biological control of snails do exist. It is almost impossible and time consuming to physically destroy the snails. Chemotherapy is costly and requires repeated treatments due to rapid re-infection. In Lake Malaŵi, chemical measures are not an option, as it would be extremely difficult to achieve molluscidal concentrations in all areas where the snails occur. The protection of molluscivorous fishes, which can change the size and species composition of snail communities in natural ecosystems, is probably the only realistic measure that can currently be taken to reduce transmission in the waters of Lake Malaŵi (Evers et al.

2006). Although there are over twenty molluscivorous fishes in Lake Malaŵi, Trematocranus

4 placodon has been considered the most important biological control agent for schistosomiasis

(Chiotha et al. 1991). T. placodon is a facultative molluscivore, can survive on diets other than snails, has strong molariform teeth on the pharyngeal bone that are used in crushing the snails, and has a lake-wide distribution. Evers et al. (2006) demonstrated that T. placodon prefers eating the thin-shelled Bulinus nyassanus, which harbors schistosomes. This has made T. placodon as a suitable candidate for snail control programs. To fully utilize this species in snail reduction, there is need to study the biology of T. placodon. This paper is aimed at determining the age and growth of T. placodon in natural populations by examining the stomach contents and daily rings on otoliths.

Methodology

Fishes were collected and processed under the research permit issued to the Molecular

Biology and Ecology Research Unit (MBERU) University of Malaŵi and the approval of the

Animal Use and Care Committee at Pennsylvania State University (IACUC #16945; 00R084).

This work was funded in part by the National Science Foundation and National Institute Health joint program in ecology of infectious diseases (DEB 0224958).

1. Collection of fish specimen

Specimens of T. placodon were collected from Lake Malaŵi in March 2007; ten specimens from Yofu Bay (Likoma Island) and another ten specimens from Crocodile Bay in equal sexes (Figure 1). Visual inspection of the genital papilla was used to identify the males and females. The fish were anaesthetized in clove oil and killed in 1 % formalin. Otoliths were extracted from the fish immediately. Each otolith was cleaned after extraction by teasing away

5 the tissues with fine tools such as forceps and dissecting needles in water. The otoliths were then air-dried and stored in microtube vials.

Figure 1. Map of Lake Malaŵi showing the sampling sites: Likoma Island and Crocodile Rock

2. Otolith preparation

Otoliths were embedded in Loctite® instant mixTM epoxy resin before sectioning.

Sectioning was done using a low-speed Isomet® (Buehler Ltd.), which is equipped with a diamond disc. Buehler® Isocut® fluid was used as the cutting fluid. Grinding and polishing of otolith sections was done by hand, using sand papers with grit grades 600 and 1000. Polished sections were then etched in 2 % hydrochloric acid for 10 to 15 seconds. They were then rinsed in water for about 2 minutes. Thereafter, the otoliths were stained with 1 % aniline blue solution

6 to reveal the fine chromophilic increments. The daily rings were then observed under a microscope at magnification of 1000x.

3. Validation of daily rings and verification

One hundred two-month old juvenile (about 2 – 3 cm total length) T. placodon were brought from Bunda College fish hatchery and raised at Pennsylvania State University wet laboratory at Rock Springs. Three of these juvenile fishes were immersed for 24 hrs in water mixed with 500 mg of oxytetracycline HCl per liter of water to mark their otoliths. The fish were then transferred to the aquarium with no oxytetracycline and left to grow for 30 days after which the fish were anaesthetized, killed, and otoliths extracted. The daily rings were read and compared against 30 days of growth by two readers. Another study (which was blind to the second reader) was conducted on three of the juvenile fishes to validate the presence of daily rings. The fish were marked oxytetracycline HCl and left to grow for a period of 68 days. The daily rings were again read and compared against 68 days of growth. Verification of the readings was done by having three samples of otoliths read by two different persons following Bellucco et al. (2004) procedure. Each reader (A and B) made two readings on each otolith (A1, A2 and B1,

B2) from a microscope. The individual results were compared and considered acceptable when the values agreed or the difference was less than 5 %. Lastly, the otolith increments were counted simultaneously by the two readers (A3, B3) on the computer screen connected to the microscope to get the final reading.

4. Storage of Fish and Otolith specimens

Fish and otoliths specimens used in this have been deposited in Pennsylvania State

University Museum. The fish specimen catalogue numbers for the fish specimen from Crocodile

Rock and Yofu Bay are PSU 6018 and PSU 6019. The otolith specimen catalogue number is

PSU 6021.

5. Data collection and analysis

Standard lengths of the specimens were measured. Stomach analyses were done to count the number of snails and identify the species. Otolith radii were measured and daily rings were estimated using the method proposed by Ralston and Miyamoto (1983) for aging adult fish using otolith daily rings. Using this method, the daily increment widths were subsampled and measured across the interpretable sections of the otolith radius. The estimated number of daily rings was then calculated by dividing the otolith radius by the estimated with of the daily increment. This estimated number of daily rings was used as an estimate of the fish age in days.

Linear regression was used to determine the relationship between growth rates (length per day) of T. placodon and the independent variables, which were sites, sex and number snails consumed. A backward selection procedure was used to identify the optimal model. All analyses were performed using R software (R Development Core Team, 2006).

Results and discussions

1. Stomach analyses of Trematocranus placodon

Trematocranus placodon in Lake Malaŵi is known to feed on gastropods (Evers et al. 2006).

In this study, stomach analyses showed that the fish predominatly fed on snails of Melanoides spp. and rarely on Bellamya sp., Bulinus nyassanus, Bulinus succinoides and Gabbiella sp (Table

1). This is because Melanoides spp. make up about 94 – 96 % of the snail fauna in Lake Malaŵi.

2. Using the sagittal otolith in determining growth in T. placodon

In this study, the sagittal otolith was used in age determination. It is generally acceptable in the literature that the term „otolith‟ is synonymous with sagitta, or the saccular otolith, primarily because all past work on aging by otoliths has been done with the sagitta (Victor and Brothers

1982). Otolith increments can provide valuable information, provided the periodicity of increment formation is validated (Campana 1995, Kristensent et al. 2008). In general, the females that were used in this study were bigger and younger than males at both sites (Figure 2).

This is not problem in age determination technique using otoliths because Ralston and Miyamoto

(1983) reported that otolith ring counts depend purely on specimen age and not otolith size.

Slow-growing fish have small otoliths, while in comparable aged fast-growing fish the otoliths were larger but contained no more increments. This demonstrates that the use of otoliths to determine growth rates of fishes collected from different areas is valid. Mendoza (2006) also reported that the most important characteristics of otoliths was the lack of resorption. This means that once the material has been deposited, the organism will not use again these minerals even in periods of starvation, which is not the case with other calcified structures like scales and bones.

3. Validation of daily rings and verification of counts in T. placodon

Campana et al. (1995) recommended that any age determination method must be tested for accuracy by an accepted age validation technique. For otoliths in this study, daily rings were validated by marking the otoliths with oxytetracycline and letting the fish grow for a specified period of time in the laboratory (Wright et al. 2002).

The number of daily increments was not exactly equal to the number of days the fish took to deposit the rings (Table 2). The problem is that it is difficult to count the daily rings on the edges which is why it was impossible to read all of them. Increments near the edge of the otoliths appeared to become laterally compressed or completely disappeared due to refraction of transmitted light through the curved surface of the age (Kristensen et al. 2008). Panella, who discovered daily rings in Merluccius productus, counted an average of 360 daily rings per year and not 365 (Victor and Brothers 1982). In this study, the greatest difference between the number of daily rings and number of days was 10.3 %, which I find acceptable.

The application of the laboratory findings may not be appropriate for wild fish. Siegfried and

Weinstein (1989) found that the fish raised in the laboratory had fewer rings than those raised in the field. This is because dairy increments formation in the wild, which is a result of endogenous circadian rhythm, may be masked by environmental factors such as temperature and feeding.

Such environmental cues tend to produce increments in addition to those produced as a result of the endogenous rhythm. In other words, the regular recurring daily increment sequence may occasionally be interspersed with subdaily increments of environmental origin (Campana 1992).

However, the visual prominence of subdaily increments is usually less than that of adjacent daily increments. In this study, more than one increment per day were rarely encountered. In addition, many studies still use laboratory-raised fish to validate daily increments and have supported the

10 hypothesis of one increment per day (HÜssy et al. 2010, Kristensen et al. 2008, Ralston and

Miyamoto 1983, Victor and Brothers 1982).

Verification of otolith counts is very important in improving accuracy. Campana (1995) reported that aging consistency can be monitored by ensuring that (1) the age interpretation does not “drift” through time, introducing bias relative to earlier determinations; (2) the age interpretations by different readers are comparable; and (3) the precision of age interpretations by individual readers does not deteriorate through time. In this study, only one otolith was read per day to avoid biases introduced due to human fatigue. Verification was done by having two independent readings of otolith increments by two different persons and also one joint reading

(Table 2). The percent difference between the two readers was less than 5 %, which is acceptable

(Bellucco et al. 2004).

4. Converting age daily increment counts to age estimates

The process of converting daily increment counts to age estimates is the most difficult one.

This is because the innermost increment does not necessarily form at hatch. Campana and Jones

(1992) recommended that experimentation or observation was required to determine the age at which the first increment was formed. Otolith counts are then initiated at any otolith landmark to which an age can be reliably and consistently assigned. They specifically recommended the use of a check formed at mouth opening. In this study, the breeding experiment of T. placodon was unsuccessful thereby preventing us from determining the age at which the first ring was formed.

Generally, cichlids have a very short larval period of less than 3 weeks (Konings 2007) and experiments at Bunda College of Agriculture, University of Malaŵi, showed that the larval period of T. placodon is about 7 to 10 days (author, personal observation). Campana (1992) also noted that there was a possibility that daily increment formation becomes intermittent in old fish

11 as somatic growth slows. Mendoza (2006) noted that otoliths provide the best biochronologies in the animal kingdom, combining annual sequences of up to 110 years in adult fishes with daily chronologies of up to a year during larval and juvenile stages. Although, the estimated age in

Table 2 may be lower than the true age, Campana and Jones (1992) reported that the number of daily increments must be proportional to, but not necessarily equal to, the age of fish. For better age estimates in adult otoliths, Campana and Jones (1992) recommended the method developed by Ralston and Miyamoto (1983) where the integrated data of number of rings in the interpretable sections of the otolith and the otolith radius in addition to a recommended validation technique can be used to estimate the age of fish. This procedure was followed in this study and the estimated age in Table 2 can be regarded as estimates of the true age.

5. Growth curves and relationship of growth rate of T. placodon to site of collection,

sex and number of snails consumed

In this sample, females were longer in standard length and younger than males from both sites (Figure 2). The effect of site was not statistically significant (p < 0.05) and was therefore removed from the models. The results of the multiple regression show that there was a significant interaction (p = 0.018) between sex and the number of snails consumed (Table 4).

The growth rate of both male and females increases as the number of snails consumed increase but the increase is higher in males than in females. This is in line with many studies that have demonstrated that in cichlid males grow bigger and faster than females (Pillay 1990).

Table 1. Number of snails by species in the stomach contents of fish.

ID Site Sex SL1 (mm) T2 S13 S24 S35 S46 S57

3803 Yofu Bay Female 147.02 56 56 0 0 0 0

3804 Yofu Bay Female 109.16 46 46 0 0 0 0

3805 Yofu Bay Female 115.6 26 23 1 0 2 0

3806 Yofu Bay Female 113.92 59 59 0 0 0 0

3808 Yofu Bay Female 114.61 41 41 0 0 0 0

3813 Yofu Bay Male 134.98 41 41 0 0 0 0

3817 Yofu Bay Male 136.48 37 37 0 0 0 0

3819 Yofu Bay Male 144.11 42 42 0 0 0 0

3821 Yofu Bay Male 136.82 16 10 3 3 0 0

3822 Yofu Bay Male 95.26 19 19 0 0 0 0

3854 Crocodile Bay Female 104.62 19 13 3 3 0 0

3855 Crocodile Bay Female 109.56 16 13 1 2 0 0

3848 Crocodile Bay Female 125.13 2 2 0 0 0 0

3860 Crocodile Bay Female 91.83 25 23 0 2 0 0

3846 Crocodile Bay Female 99.48 12 9 0 2 0 1

3847 Crocodile Bay Male 115.71 22 18 1 1 1 1

3853 Crocodile Bay Male 114.76 20 16 3 1 0 0

3862 Crocodile Bay Male 83.98 9 8 0 1 0 0

3867 Crocodile Bay Male 76.77 5 5 0 0 0 0

3850 Crocodile Bay Male 96.81 11 11 0 0 0 0

1Standard length of in mm 5Number of snails belonging to Bulinus nyassanus

2Total number of snails found in the fish‟s stomach 6Number of snails belonging to Bulinus succinoides

3Number of snails belonging to Melanoides spp 7Number of snails belonging to Bellamya spp.

4Number of snails belonging to Gabbiella spp

Table 2. Validation of daily rings in T. placodon (N = 6) and verification of daily increments counts by two readers A and B.

Daily increments Daily increments Difference Joint Difference

read by A read by B between reading between days

readers A and and growth A1 A2 Mean B1 B2 Mean Days B (%) increments (%)

30 27 26 27 25 27 26 3.7 28 6.7

30 26 27 27 28 27 28 3.6 28 6.7

30 27 27 27 27 26 27 0.0 28 6.7

68 57 56 57 57 59 58 1.7 62 8.8

68 61 60 61 61 63 62 1.6 61 10.3

68 56 54 55 56 56 56 1.8 64 5.9

Table 3. Growth rate (mm/day) of males and females of T. placodon collected from Yofu Bay and Crocodile Bay, Lake Malaŵi using estimated sagittal otolith daily increments

ID Otolith diameter Estimated age in Growth rate

Site Sex SL (mm) (m) days (mm/day)

3803 Yofu Bay Female 147.02 1850 617 0.238282

3804 Yofu Bay Female 109.16 1400 590 0.185017

3805 Yofu Bay Female 115.6 1550 579 0.199655

3806 Yofu Bay Female 113.92 1500 581 0.196076

3808 Yofu Bay Female 114.61 1500 593 0.193272

3813 Yofu Bay Male 134.98 1650 523 0.258088

3817 Yofu Bay Male 136.48 1700 532 0.256541

3819 Yofu Bay Male 144.11 2100 593 0.243019

3821 Yofu Bay Male 136.82 1650 526 0.260114

3822 Yofu Bay Male 95.26 1150 534 0.17839

3854 Crocodile Bay Female 104.62 1250 581 0.180069

3855 Crocodile Bay Female 109.56 1300 592 0.185068

3848 Crocodile Bay Female 125.13 1600 614 0.203795

3860 Crocodile Bay Female 91.83 950 563 0.163108

3846 Crocodile Bay Female 99.48 1000 564 0.176383

3847 Crocodile Bay Male 115.71 1050 514 0.225117

3853 Crocodile Bay Male 114.76 1150 530 0.216528

3862 Crocodile Bay Male 83.98 950 496 0.169315

3867 Crocodile Bay Male 76.77 900 501 0.153234

3850 Crocodile Bay Male 96.81 1000 501 0.193234

Table 4. Regression analysis of the relationships of sex, number of snails consumed and their interaction on growth rate (mm/day) of T. placodon (N = 20 fish).

Independent variables Estimate Standard errors t - value p - value

Sexa -0.0143 0.0142 -0.697 0.4957

Snails 0.0005 0.0205 1.126 0.2766

Sex*Snails interaction 0.0019 0.0004 2.636 0.0180*

Constant 0.1784

R2 0.5811 a Sex is coded as 0 for females and 1 for males

*significant at 0.05 (2-tailed test)

Figure 2. Scatterplot of length (mm) versus age (days) for females and males of T. placodon.

Open circles: females from Yofu Bay; solid circles: females from Crocodile Bay; open rectangles with open circles: males from Yofu Bay; and solid rectangles: males from Crocodile

Bay.

Conclusion and recommendations

This study demonstrated that Trematocranus placodon deposits daily rings and that adult otoliths can be used in age estimation by using the procedure developed by Ralston and

Miyamoto since the daily rings are not visible in all sections of the otoliths. The study also showed that the growth rate of T. placodon is determined by the interaction of sex and the number of snails consumed.

This study had a few limitations. Firstly, the fish that were used in the growth determination were between 90 and 150 mm standard length. Future studies of age determination of T. placodon should improve sampling of the specimen. Campana and Jones (1992) recommended that growth rate calculations of a species require complete and representative sampling of all relevant cohorts and life history stages. Secondly, validation method used in this study was that of chemical marking using oxytetracycline HCL. Mendoza (2006) mentioned several validation techniques that include chemical marking, length-frequency, identification of the first annulus, marginal increment analysis and tag-recapture analysis. Based on the first recommendation, the marginal increment method should be used in the validation method. This procedure estimates the marginal increment of the otolith of each fish for age class and estimates the profile of the mean monthly marginal increment.

Chapter 3: Systematics of the cichlid genus Mylochromis, Regan

Introduction

The genus Mylochromis consists of species that are distinguished by a dark diagonal stripe

(Eccles and Trewavas 1989, Konings 2007, Spreinat 1995). The diagonal striped pattern is associated with a number of very different morphologies, which are placed into a variety of genera (Turner 1996). Members of the genus Mylochromis appear to be relatively unspecialized in contrast to other cichlids that also exhibit a diagonal stripe, but are characterized by other features as well and placed in separate genera. For example, members of the genus

Buccochromis have a diagonal stripe, a large mouth and a predatory lifestyle, while members of the genus Lichnochromis have a diagonal stripe and a laterally compressed snout (Spreinat

1995).

In terms of feeding behavior, species like M. anaphyrmus, M. epicholiaris, M. mola, M. sphaerodon and M. subocularis are snail eaters. Species like M. chekopae feeds on planktonic vertebrates and algae. M. ensatus feeds on invertebrates that it finds on sand. M. formosus, M. gracilis and M. spilostichus are piscivores. M. guentheri collects detritus from the surface of the sand. M. melanonotus is attracted to large black catfishes and snatches fry from the catfish nest.

M. labidodon and M. lithoschalis roll over pebbles looking for invertebrates to eat. M. lateristriga and M. melanotaenia dig into the sand and filters any palatable items. M. lateristriga mainly eats crustaceans and insect larvae while M. melanotaenia sucks out snails from their shells. M. obtusus robs eggs from mouth breeding females. Juveniles of M. melanonotus start out as cleaners and become piscivores when adults (Konings 2007).

The diagonal stripe pattern is unique to Lake Malaŵi cichlids (Spreinat 1995). The stripe varies among species, with the band differing in position, intensity, and/or continuity; sometimes being irregular or broken into a series of spots that may be more or less elongated in the direction of the band (Eccles and Trewavas 1989).

Presently, the genus Mylochromis has 21 species (Table 5). There are many more populations that appear to be new species (as shown in Table 6 with their working names) based on their shape, behavior, color and location.

Eccles and Trewavas (1989) described the genus Maravichromis and designated

Maravichromis ericotaenia as the type species. One of the species they included in the new genus was Maravichromis lateristriga. Unknown to the authors, M. lateristriga was already designated as the type specimen of the genus Mylochromis by Regan in 1920. In this case, a genus name already existed for species with a diagonal stripe and Mylochromis being the older name, took priority over Maravichromis. Therefore, Maravichromis became a junior synonym of

Mylochromis (Derijst and Snoeks 1992).

In erecting the genus Maravichromis, Eccles and Trewavas (1989) noted that this genus was an unsatisfactory grouping because they were unable to identify synapomorphies to diagnose it from other genera with a diagonal stripe. They believed that it was possible that some members of the genus might be closely related to genera such as Buccochromis and Caprichromis, although they were unable to establish such links. Snoeks and Hanssens (2004) found undescribed taxa that seem to bridge the gaps between Mylochromis and two other genera,

Sciaenochromis and Stigmatochromis. They also think that Mylochromis gracilis and

Mylochromis spilostichus should be placed in the genus Sciaenochromis. They further believe

20 that the predatory looking elongate species Mylochromis gracilis and Mylochromis spilostichus have more affinities with Sciaenochromis than with other taxa of Mylochromis. Therefore, they concluded that the genus Mylochromis is polyphyletic and recommended that this genus was in desperate need of revision. Turner (1996) also reported that some of the Mylochromis species have never been positively recorded since their original description.

Morphometrics involve the quantitative study of form, which consists of size and shape

(Richtsmeier 2002). Size describes the magnitude of a given character, whereas shape implies the relationship between two or more characters (Somers 1986). The measures we collect to study form contain information pertaining to a combination of size and shape. A great deal of effort has been targeted at developing ways to separate these intertwined components though such attempts often remove biologically interesting information from the analysis (Richtsmeier

2002). One reason why one might wish to analyze shape differences among populations separately from size differences is that size is labile ontogenetically and phylogenetically. Should a sample for one population contain more juveniles than another, then observed differences would not be the same as those found when one compares the populations at another time of the year (Rohlf and Bookstein 1987). The effects of general size on morphometric data have commonly been removed using bivariate methods (e.g., ratios to standard distance and residuals of a regression on a standard distance). These traditional approaches are generally ineffective for removing size variance from data because they only remove the effect of the standard distance, which is not a comprehensive measure of general size (Cadrin 2000). Rohlf and Bookstein

(1987) recommended the use of “shearing” for multivariate discrimination by shape in the presence of size variation.

Taxonomic Analysis: Mylochromis Regan

Type species: Mylochromis lateristriga (Regan, 1920)

Diagnosis

Haplochromines endemic to Lake Malaŵi, resembling Buccochromis. Principal melanin pattern an oblique stripe or series of spots from nape to base of caudal, but having smaller mouth with lower jaw 2.3 to 3.4 times in head length and less numerous close-set outer teeth, 30 to 64 in outer series of upper jaw (58 to 92 in Buccochromis). Outer teeth usually bicuspid but simple in adults of some species (Eccles and Trewavas (1989).

Methodology

Fishes were collected and processed under the research permit issued to the Molecular

Biology and Ecology Research Unit (MBERU) University of Malaŵi and the approval of the

Animal Use and Care Committee at Pennsylvania State University (IACUC #16945; 00R084).

This work was funded in part by the National Science Foundation and National Institute of

Health joint program in ecology of infectious diseases (DEB 0224958).

Described specimens were borrowed from the British Museum of Natural History (BMNH) and the United States Museum of Natural History (USNH) as shown in Table 1. Undescribed populations of Mylochromis were collected from various placed in Lake Malaŵi by chasing them into a monofilament block net while SCUBA diving (Table 6 and Figure 2). All fishes were

22 anesthetized with clove oil, euthanized in 1 % formalin, and pinned in trays so that the bodies were flat and the fins erect. The fish were then preserved in 10 % formalin, and stored in 70 % ethanol. Pigmentation patterns and color were recorded in the field via direct observation, photography, and videography. Counts and measurements follow Stauffer (1991) and Stauffer and Konings (2006) (Table 7). All measurements were taken from the left side of the body with the exception of gill-raker counts, which were taken on the right side (Figure 4). Morphometric data were analyzed using sheared principal components analysis, which factors the covariance matrix and restricts size variation to the first principal components (Humphries et al. 1981,

Bookstein et al. 1985). Meristic data were analyzed using principal components analysis in which the correlation matrix was factored. Differences in character states were used to diagnose each species. In some instances, the morphometric and meristic data overlapped for different species. In such instances, I plotted the sheared second principal components (SPC2) of the morphometric data against the first principal components (PC1) of the meristic data to further search for differences (Stauffer and Hert, 1992).

Table 5. Described species of the genus Mylochromis that were examined

Number of fish Date

Species Name Collection ID Location collected examined

Mylochromis 3 miles southwest of Monkey anaphyrmus USNM 210699 Bay, Lake Malaŵi 3/24/1973 1

Mylochromis BMNH1935.6.14.2420- balteatus 2422 Karonga, Lake Malaŵi 1935 3

Lake Malaŵi, off Chekopa

Mylochromis North-Eastern Shore of SE chepokae BMNH1996.10.14.99-120 Arm 19/11/1991 22

Mylochromis Lake Malaŵi, White Rock and ensatus BMNH.1996.10.14.124 Namiasi 21/10/1991 10

Mylochromis BMNH1935.6.14.2426- epichorialis 2427 Deep Bay, Lake Malaŵi ** 2

Mylochromis ericotaenia BMNH1921.9.6.148-149 Lake Malaŵi* ** 2

Mylochromis BMNH1935.6.14.1454- formosus 1455 Vua, Lake Malaŵi 4/18/1905 2

Mylochromis BMNH1935.6.14.1456- gracilis 1458 Monkey Bay, Lake Malaŵi ** 3

Mylochromis guentheri BMNH1908.10.27.85 Lake Malaŵi* 4/5/1905 1

Mylochromis BMNH1935.6.14.2341- incola 2347 Mangochi, Lake Malaŵi ** 9

Mylochromis BMNH1935.6.14.2417- Mwaya, Lake Malaŵi, labidodon 2419 Tanzania ** 1

Mylochromis labidodon BMNH1935.6.14.2416 Deep Bay, Lake Malaŵi ** 3

Mylochromis lateristriga BMNH1908.10.27.76-85 Lake Malaŵi* ** 15

Mylochromis melanonotus BMHN1921.9.6.163-164 Lake Malaŵi* ** 1

Mylochromis melanotaenia BMNH1921.9.6.151-153 Lake Malaŵi* 4/5/1905 3

Mylochromis mola BMNH1935.14.2357-2359 Vua, Lake Malaŵi ** 3

Mylochromis Monkey Bay + S. W. Arm, mollis BMNH1935.6.14.1334 Lake Malaŵi ** 2

Mylochromis obtusus BMNH1935.6.14.1453 Bar-N'kudzi, Lake Malaŵi ** 1

Mylochromis BMNH1935.6.14.1321- Deep Bay + Kapora, Lake semipalatus 1323 Malaŵi ** 2

Mylochromis sphaerodon BMNH1921.9.6.146-147 Lake Malaŵi ** 2

Mylochromis spilostichus BMNH1935.6.14.1459 Monkey Bay, Lake Malaŵi ** 1

Mylochromis Lake Malaŵi and the Upper subocularis BMNH1893.11.15.24-32 Shire River ** 11

*No specific location was given

**No date was recorded

Table 6. Undescribed population of the genus Mylochromis from the Pennsylvania State University fish museum.

Working name Collection ID* Place Date Number of fish

Cyrtocara sp. JRS-85-19 Nakanthenga Island 3/14/1995 2

Obliquestripe

Mylochromis JRS-05-14 Nkhwazi ,Tanzania 2/10/2005 2

Mylochromis "incola JSR-04-179 Boadzulu Island NW Corner 10/31/2004 1 boadzulu"

Mylochromis JRS-04-31 Thumbi East Island 2/8/2004 20 anaphyrmus

Mylochromis MEA.95.26 SE Arm of L. Malawi 17/12/1995 17 anaphyrmus

Mylochromis c.f. JRS-95-49 Harbor Island 2/24/1995 5 mola

Mylochromis cf MEA95.26 SE Arm of L. Malawi 17/12/1995 6 anaphyrmus

Mylochromis cf JRS-04-28 Otter Point 2/7/2004 3 balteatus

Mylochromis cf. AFK03-6 Likoma Island, Lake Malawi 10/23/2003 19 mollis

Mylochromis JRS-04-32 Boadzulu Island 1/9/2004 1 epichorialis

Mylochromis formosa JRS-05-15 Magunga 2/11/2005 1

Mylochromis incola JRS-04-32 Boadzulu Island 1/9/2004 9 boadzulu

Mylochromis incola JRS-04-37 Mumbo Island 2/12/2004 12 mumbo

Mylochromis JRS-04-28 Otter Point 2/7/2004 2 lateristriga

Mylochromis JRS-05-10 Lupingu, Tanzania 2/8/2005 4 lateristriga lupinga

Mylochromis Nkhata-Bay 01/01/2010 10 lateristriga

Nkhatabay**

Mylochromis JRS-04-6 Pombo Rocks Tanzania 1 melanonotus

Mylochromis mola JRS-04-6 Pombo Rocks Tanzania 4

Mylochromis mola JRS-04-28 Otter Point 2/7/2004 12

Mylochromis mollis JRS-04-211 Thumbi Point 1/27/2004 1

Mylochromis JRS-04-28 Otter Point 2/29/2004 23 plagiotaenia

Mylochromis sp JRS-03-104 Msaka Island 4/11/2003 4

Mylochromis sp 1 JSR-03-95 Cape Maclear 4/9/2003 11

Mylochromis sp 3 JRS-03-95 Cape Maclear 4/9/2003 2

Mylochromis sp 5 JRS-03-95 Cape Maclear 4/9/2003 1

*The fish were collected by Dr. Ad Konings (AFK) of Cichlid Press, USA or Jay R. Stauffer, Jr. (JRS) of

Pennsylvania State University

**This fish was collected from Lake Malaŵi and sent directly to the Ichthyology Laboratory with being logged into the Pennsylvania State University Fish Museum.

Figure 3. Truss diagram showing the morphometric measurements (white lines) and where meristic counts were taken (black lines).

Figure 4. Map of Lake Malaŵi showing the places where the undescribed specimens of the genus Mylochromis were collected.

Table 7. The morphometric and meristic measurements that were taken from each fish specimen

to be used in the sheared principal components analysis.

Morphometric measurements Meristic counts

1. Standard length, mm 1. Dorsal-fin spines

2. Head length 2. Dorsal-fin rays

3. Snout to dorsal-fin origin 3. Anal-fin spines

4. Snout to pelvic-fin origin 4. Anal-fin rays

5. Dorsal-fin base length 5. Pectoral-fin rays

6. Anterior dorsal to anterior anal 6. Pelvic-fin rays

7. Anterior dorsal to posterior anal 7. Lateral-line scales

8. Posterior dorsal to anterior anal 8. Pored scales posterior of lateral line

9. Posterior dorsal to posterior anal 9. Scale rows on cheek

10. Posterior dorsal to ventral caudal 10. Gill rakers on first ceratobranchial

11. Posterior anal to dorsal caudal 11. Gill rakers on first epibranchial

12. Anterior dorsal to pelvic-fin origin 12. Teeth in outer row of left lower jaw

13. Posterior dorsal to pelvic-fin origin 13. Teeth rows on upper jaw

14. Caudal-peduncle length 14. Teeth rows on lower jaw

15. Least caudal-peduncle depth

16. Body depth

17. Snout length

18. Postorbital head length

19. Horizontal eye diameter

20. Vertical eye diameter

21. Preorbital length

22. Cheek depth

23. Lower-jaw length

24. Head depth

A. Described Species

1. Mylochromis lateristriga (GÜnther 1864) – Type species of the genus Mylochromis

Figure 5. Mylochromis lateristriga (GÜnther). BMNH 1921.9.6.150, 155 mm standard length. Source: Eccles and Trewavas, 1989.

Material examined

BMNH1908.10.27.76-85; 16; 54.4 – 153.9 mm SL; Lake Malaŵi.

Diagnosis

Mylochromis lateristriga along with Mylochromis balteatus, Mylochromis incola,

Mylochromis melanotaenia, Mylochromis mola, Mylochromis sphaerodon and Mylochromis subocularis has a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than 40 % SL and dorsal spines less than 17.

Mylochromis lateristriga has a shorter snout length (31 – 40 % versus 39 – 43 % HL), a smaller cheek depth (18 – 26 % versus 22 – 29 HL) and a larger vertical eye diameter (26 – 57 % versus 28 – 32 HL) than M. balteatus. Meristically, M. lateristriga has fewer lateral line scales

(26 – 32 versus 31 – 32) than M. balteatus. Mylochromis lateristriga has a snout length (31 – 40

% versus 39 – 46 % HL), a longer dorsal fin base length (51 – 56 % versus 48 – 52 % SL) and a longer horizontal eye diameter (26 – 40 % versus 28 – 33 % HL) than M. incola. There is a lot of overlap in both morphometric measurements and meristic counts between M. lateristriga and M. melanotaenia. Mylochromis lateristriga has fewer lateral line scales (26 – 32 versus 31 – 32) and fewer cheek scales (2 – 4 versus 4) than M. melanotaenia. There is a lot of overlap in both morphometric measurements and meristic counts between M. lateristriga and M. mola.

Mylochromis lateristriga has a shorter snout length (31 – 40 % versus 38 – 44 % HL) than M. mola. There is a lot of overlap in both morphometric measurements and meristic counts between

M. lateristriga and M. sphaerodon. M. lateristriga has a shorter snout to dorsal fin origin length than M. sphaerodon (35 – 40 % versus 37 – 42 % SL). Mylochromis lateristriga has a longer caudal peduncle length (18 – 20 % versus 15 – 18 % SL) and more dorsal rays (10 – 12 versus 8

– 10) than M. subocularis.

Description

Morphometric and meristic data in Table 6. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 15 - 16 spines (mode 15) and 10 - 12 dorsal rays (mode 11). Anal fin with 3 spines and 7 - 9 anal rays (mode 8). Lateral lines scales 26 - 32 (mode 28) with 0 - 1 pored scales (mode 0). Gill rakers on first ceratobranchial 8 – 12 (mode 9) and on first epibranchial 3 – 4 (mode 4).

Females and immature males silvery, darker dorsally with conspicuous black oblique bar.

Ripe males blue, turquoise or yellowish ventrally with orange margin to flank scales. Dorsal and caudal fins with orange-red spots. Dorsal margin white with red-tipped lappets. Anal dark with broad orange distal margin and numerous with spots and streaks (Turner 1996).

Field observations

Mylochromis lateristriga digs into the sand and filters any palatable items (mainly crustaceans and insect larvae) from it. It is often found among groups of the leaf-cleaning

Hemitilapia. A male secures a breeding territory shortly before spawning and attracts a ripe female into following him to his spawning site, usually a shallow saucer-shaped pit dug in the sand, although a flat stone may be chosen instead. During spawning, the eggs are immediately collected by the female before being fertilized inside her mouth (Konings 2007).

Distribution

Mylochromis lateristriga is frequently encountered in the southern part of the lake (Konings

2007).

Discussion

Although there was an overlap between the character states of Mylochromis lateristriga and

Mylochromis balteatus, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 6).

Figure 6. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lateristriga and M. balteatus.

Although there was an overlap between the character states of M. lateristriga and M. incola, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 7).

M. lateristriga M. incola

0.10

)

l 0.05

l o

h 0.00

(

2 -0.05

D R

H -0.10 S

-0.15 -2 -1 0 1 2 PCA1 (meristic data)

Figure 7. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lateristriga and M. incola.

Although there was an overlap between the character states of M. lateristriga and M. melanotaenia, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 8).

Figure 8. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lateristriga and M. melanotaenia.

Although there was an overlap between the character states of M. lateristriga and M. mola, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 9).

Figure 9. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lateristriga and M. mola.

Although there was an overlap between the character states of M. lateristriga and M. sphaerodon, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 10).

Figure 10. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lateristriga and M. sphaerodon.

Although there was an overlap between the character states of M. lateristriga and M. subocularis, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 11).

Figure 11. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lateristriga and M. subocularis.

2. Mylochromis anaphyrmus (Burgess and Axelrod, 1973)

Figure 12. Mylochromis anaphyrmus. Source: www.malawicichlids.com

Material examined

USNM210699, holotype; 159.1 mm SL; Lake Malaŵi, 4.8 km South-West of Monkey Bay;

24th March 1973.

Diagnosis

Mylochromis anaphyrmus can be distinguished from all members of this genus by having a snout to dorsal fin origin length of greater than 35 % standard length and a post-orbital head length of 45 % HL.

Description

Morphometric and meristic data in Table 8. Solid diagonal stripe along side of body. Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile

42 convex. Dorsal fin with 16 spines and 12 dorsal rays. Anal fin with 3 spines and 8 anal rays.

Lateral lines scales 33 with no pored scales. Gill rakers on first ceratobranchial 8 and on first epibranchial 5.

Silvery on flanks, darker dorsally often with metallic green cast. Females and immature males with conspicuous black oblique bar. Ripe males pale turquoise on head and back. Dorsal fins bright yellow lappets. Anal fin with yellow lower margin and numerous egg-spots (Turner

1996).

Field observations

Mylochromis anaphyrmus is a snail-crusher. It is frequently seen foraging on the sandy bottom. It is more robust and seems to be more restricted to the deeper regions of the shoreline

(Konings 2007). A small breeding arena at 5 m depth was observed. Males constructed small, asymmetrical bowers. These fish were not collected, and it is not certain that they were M. anaphyrmus (Spreinat 1995).

Distribution

It is endemic to the southern and western part of the lake (Konings 2007).

3. Mylochromis balteatus (Trewavas 1935)

Figure 13. Mylochromis balteatus (Trewavas). Lectotype. female, 125 mm standard length Source: Eccles and Trewavas (1989)

Material examined

BMNH1935.6.14.2420-2422; lectotype; 3; 85.1 – 130.3 mm SL; Lake Malaŵi, Karonga;

1935.

Diagnosis

Mylochromis balteatus along with Mylochromis incola, Mylochromis lateristriga,

Mylochromis melanotaenia, Mylochromis mola, Mylochromis sphaerodon and Mylochromis subocularis have a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than 45 % HL.

Mylochromis balteatus has a shorter snout to pelvic fin origin length (39 – 41 % versus 42 –

47 % SL) than M. incola. Mylochromis balteatus has a longer snout length (39 – 43 % versus 31

– 40 % HL), a deeper cheek depth (22 – 29 % versus 18 – 26 % HL), a smaller vertical eye diameter (28 – 32 versus 26 – 57 % HL) and more lateral line scales (31 – 32 versus 26 – 32) than M. lateristriga. Mylochromis balteatus has a longer preorbital head length (29 – 35 % versus 26 – 27 % HL) and more teeth on the left lower jaw (13 – 15 versus 10 – 12) than M. melanotaenia. Mylochromis balteatus has a shorter snout to pelvic fin origin length (39 – 41 % versus 42 – 43 % SL), fewer teeth rows on lower jaw (4 versus 6) and fewer teeth rows on upper jaw (3 – 5 versus 6) than M. mola. Mylochromis balteatus has a deeper cheek depth (22 – 29 % versus 20 % HL), a shorter post dorsal to post anal length (13 – 15 % versus 29 % SL) and a larger snout length (39 – 43 % versus 35 – 36 % HL), more lateral line scales (31 – 32 versus 30) and fewer teeth rows on lower jaw (4 versus 5) than M. sphaerodon. Mylochromis balteatus has more lateral line scales (31 – 32 versus 26 – 30) and more pectoral rays (14 versus 10 – 13) than

M. subocularis.

Description

Morphometric and meristic data in Table 8. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 15 - 16 spines (mode 15) and 12 dorsal rays. Anal fin with 3 spines and 8 anal rays. Lateral lines scales 31 – 32 (mode 31) with 1 pored scale. Gill rakers on first ceratobranchial 3 – 4 (mode 3) and on first epibranchial 8 – 10 (mode 8).

Color description not available for live specimens.

Field observations: None

Discussion

Although there was an overlap between the character states of M. balteatus and M. lateristriga, analysis of the sheared principal components of the morphometric data and the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 14).

Figure 14. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. balteatus and M. lateristriga.

4. Mylochromis chekopae (Turner and Howarth 2002)

Figure 15. Mylochromis chekopae (Turner and Howarth) Source: Konings 2007

Material examined

BMNH1996.10.14.99-120; 23; 103.3 – 122.4 mm SL; Lake Malaŵi off Chekopa North-

Eastern Shore of South East arm.

Diagnosis

Mylochromis chekopae, along with Mylochromis ensatus, Mylochromis ericotaenia,

Mylochromis formosus, Mylochromis gracilis, Mylochromis guentheri and Mylochromis labidodon have a snout to dorsal-fin origin length of less than 35 % of the standard length and a snout length of greater than 25 % head length.

Mylochromis chekopae has a deeper body depth (30 – 34 % versus 23 – 28 % HL) than M. ensatus. Mylochromis chekopae has a larger head depth (65 – 90 % versus 53 – 60 % HL), a longer snout (30 – 38 % versus 27 – 29 % HL), more gill rakers on the first ceratobranchial (12 –

16 versus 8 – 9) and more lateral line scales (32 – 36 versus 31) than M. ericotaenia.

Mylochromis chepokae has a larger head depth (65 – 90 % versus 54 – 56 % HL), more gill rakers on the first ceratobranchial (12 – 16 versus 9), more dorsal rays (12 – 13 versus 11) and more cheek scales 3 – 4 versus 2) than M. formosus. Mylochromis chepokae has a larger body depth (65 – 90 % versus 26 - 27 % HL) and a shorter preorbital head length (22 – 29 % versus 34

– 36 % HL) than M. gracilis. Mylochromis chepokae has more gill rakers on the first ceratobranchial (12 – 16 versus 9) and more dorsal rays (12 – 13 versus 10) than M. guentheri.

Mylochromis chepokae has a longer posterior dorsal to anterior anal length (29 – 33 % versus 26

– 28 % SL), more dorsal rays (12 -13 versus 10 – 11), more gill rakers on the first ceratobranchial (12 – 16 versus 9) and more dorsal rays (12 – 13 versus 10 - 11) than M. labidodon.

Description

Morphometric and meristic data in Table 8. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 15 – 17 spines (mode 17) and 12 – 13 dorsal rays (mode 13).

Anal fin with 3 spines and 8 - 9 anal rays (mode 9). Lateral lines scales 32 – 36 (mode 34) with 0

- 2 pored scales (mode 1). Gill rakers on first ceratobranchial 12 – 16 (mode 13) and on first epibranchial 4 – 5 (mode 5).

Color description not available for live specimens.

Field observations

Mylochromis chekopae feeds on planktonic invertebrates and algae and that it feeds apparently from the water column as no sand grains have been found in stomach inventories

(Konings 1007).

Distribution

Mylochromis chekopae is found in the southern part of the lake (Konings 2007). It is known from shallow waters (18 – 45 meters) off the north-eastern shore of the South-East Arm of the lake (Turner 1996).

Table 8. Morphometric and meristic values of Mylochromis anaphyrmus (n = 1), Mylochromis

balteatus (n = 3) and Mylochromis chekopae (n = 23)

M. anaphyrmus M. balteatus M. chekopae

(n = 1) (n = 3) (n = 23)

range range

Standard length, mm 159.1 85.1 – 130.3 103.3 – 122.4

Head length, mm 52 29.2 – 48.2 29.6 – 35.0

Percent standard length

Head length 33 34 – 37 27 – 32

Snout to dorsal-fin origin 37 41 – 43 30 – 34

Snout to pelvic-fin origin 38 39 – 41 35 – 41

Dorsal-fin base length 60 51 - 56 57 – 60

Anterior dorsal to anterior anal 55 46 - 50 46 – 51

Anterior dorsal to posterior anal 64 55 – 60 59 – 63

Posterior dorsal to anterior anal 33 26 – 32 29 – 33

Posterior dorsal to posterior anal 17 13 – 15 13 – 16

Posterior dorsal to ventral caudal 20 19 17 – 21

Posterior anal to dorsal caudal 23 19 – 22 19 – 22

Anterior dorsal to pelvic-fin origin 42 33 – 40 31 – 35

Posterior dorsal to pelvic-fin origin 55 48 – 58 52 – 59

Caudal-peduncle length 19 19 17 – 20

Least caudal-peduncle depth 12 10 – 12 9 – 11

Body depth 40 34 – 39 30 – 34

Percent head length

Snout length 33 39 – 43 30 – 38

Postorbital head length 45 37 – 41 37 – 42

Horizontal eye diameter 26 27 – 36 30 – 35

Vertical eye diameter 28 28 – 32 29 – 36

Preorbital length 31 29 – 35 22 – 29

Cheek depth 26 22 – 29 17 – 23

Lower-jaw length 33 31 – 40 31 – 36

Head depth 70 65 – 70 65 – 90

Counts

Dorsal-fin spines 16 15 – 16 15 – 17

Dorsal-fin rays 12 10 – 11 12 – 13

Anal-fin spines 3 3 3

Anal-fin rays 8 8 8 – 9

Pectoral-fin rays 13 14 12 – 14

Pelvic-fin rays 5 5 5

Lateral-line scales 33 31 – 32 32 – 36

Pored scales posterior of lateral line 0 0 – 1 0 – 2

Scale rows on cheek 4 3 – 4 3 – 4

Gill rakers on first ceratobranchial 8 8 – 10 12 – 16

Gill rakers on first epibranchial 3 3 – 4 4 – 5

Teeth in outer row of left lower jaw 12 13 – 16 8 – 19

Teeth rows on upper jaw 6 3 – 5 3 – 12

Teeth rows on lower jaw 9 4 2 – 8

5. Mylochromis ensatus (Turner and Howarth 2002)

Figure 16. Mylochromis ensatus (Turner and Howarth) Source: Konings 2007

Material examined

BMNH.1996.10.14.124 – 126; 10; 92.1 – 203.4 mm SL; White Rock and Namiasi, Lake

Malaŵi; 21st October 1991.

Diagnosis

Mylochromis ensatus along with Mylochromis chekopae, Mylochromis ericotaenia,

Mylochromis formosus, Mylochromis gracilis, Mylochromis guentheri and Mylochromis labidodon have a snout to dorsal fin origin length of less than 35 % of the standard length and a snout length of greater than 25 % head length.

Mylochromis ensatus has a narrower body depth (23 – 28 % versus 30 – 34 % HL) than M. chepokae. Mylochromis ensatus has more anal rays (9 versus 7 – 8), more lateral line scales (34

– 37 versus 31), more cheek scales (3 – 4 versus 2) and more gill rakers on the first ceratobranchial (11 – 14 versus 8 – 9) than M. ericotaenia. Mylochromis ensatus has longer preorbital head length (28 – 36 % versus 24 – 25 % HL) and a narrower least caudal peduncle depth (9 – 10 % versus 11 % SL), more cheek scales (3 – 4 versus 2) and more gill rakers on the first ceratobranchial (11 – 14 versus 9) M. formosus. Mylochromis ensatus has a longer snout length (33 – 34 % versus 28 – 30 % HL) and more teeth rows on upper jaw (4 – 7 versus 3) than

M. gracilis. Mylochromis ensatus has a longer post dorsal to anterior anal length (27 – 29 % versus 25 % SL), more anal rays (9 versus 8), more dorsal rays (11 – 13 versus 10), more teeth rows on lower jaw (4 – 6 versus 2) and more gill rakers on the first ceratobranchial (11 – 14 versus 9) than M. guentheri. Mylochromis ensatus fewer anal rays (9 versus 10 – 11) than M. labidodon.

Description

Morphometric and meristic data in Table 9. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 16 – 17 spines (mode 17) and 11 – 13 dorsal rays (mode 13).

Anal fin with 3 spines and 9 anal rays. Lateral lines scales 34 – 37 (mode 35, 36) with 0 - 1 pored scales (mode 1). Gill rakers on first ceratobranchial 11 – 14 (mode 12) and on first epibranchial

Color description not available for live specimens

Field observations

Mylochromis ensatus is found over sandy bottoms. It feeds on invertebrates that it finds on the sand. It never scoops up sand but quickly screens the bottom for anything edible and moves rather quickly through the habitat (Konings 2007).

Distribution

Mylochromis ensatus occurs in the southern part of the lake (Konings 2007).

6. Mylochromis epicholiaris (Trewavas 1935)

Figure 17. Mylochromis epicholiaris (Trewavas). Lectotype, female, 170 mm standard length. Source: Eccles and Trewavas (1989).

Material examined

BMNH1935.6.14.2426-2427; 2; syntypes; 166.2 – 166.5 mm SL; Lake Malaŵi, Deep Bay; 1935.

Diagnosis

Mylochromis epicholiaris along with Mylochromis obtusus have a snout to dorsal fin origin length of more than 35 % of standard length and a preorbital head length of more than 40 % of head length. M. epicholiaris has a smaller head depth (61 – 69 % versus 81 % HL) and a shorter anterior dorsal to anterior anal fin origin length (45 – 46 % versus 52 % SL) than M. obtusus.

Meristically, M. epicholiaris has more dorsal spines (17 versus 16) and fewer gill rakers on the first ceratobranchial (10 versus 12) than M. obtusus.

Description

Morphometric and meristic data in Table 9. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 15 – 17 spines (mode 17) and 12 – 13 dorsal rays (mode 13).

Anal fin with 3 spines and 8 - 9 anal rays (mode 9). Lateral lines scales 32 – 36 (mode 34) with 0

- 2 pored scales (mode 1). Gill rakers on first ceratobranchial 12 – 16 (mode 13) and on first epibranchial 4 – 5 (mode 5).

Color description not available for live specimens.

Field observations

At many different locations, Mylochromis epicholiaris has been observed attacking and eating crabs (Potamonautes orbitospinus) and it is likely that M. epicholiaris, at least as far as

56 adult specimens are concerned, has specialized in feeding on these large crustaceans. Males in breeding color are rare but when encountered are always in shallow water and also in the water column. Spawning sites have not been seen but it is possible that they breed inside caves which they quickly abandon when approached by a diver (Konings 2007).

Distribution

Mylochromis epicholiaris has a lakewide distribution but is a rare sight at any location

(Konings 2007).

7. Mylochromis ericotaenia (Regan 1922)

Figure 18. Mylochromis ericotaenia (Regan). Lectotype, 59 mm standard length. Source: Eccles and Trewavas (1989).

Material examined

BMNH1921.9.6.148-149; syntypes; 2; 50.5 – 50.1 mm SL; Lake Malaŵi.

Diagnosis

Mylochromis ericotaenia along with Mylochromis chekopae, Mylochromis ensatus,

Mylochromis ericotaenia has a narrower head depth (53 – 60 % versus 65 – 90 % % HL) and a shorter snout length (27 – 29 % versus 30 – 38 % HL), fewer gill rakers on the first ceratobranchial (8 – 9 versus 12 – 16) and fewer lateral line scales (31 versus 32 – 36) than M. chekopae. Mylochromis ericotaenia can be distinguished by fewer anal rays (7 – 8 versus 9), less lateral line scales (31 versus 34 – 37), fewer cheek scales (2 versus 3 – 4) and fewer gill rakers on the first ceratobranchial (8 – 9 versus 11 – 14) than M. ensatus. Mylochromis ericotaenia has a smaller cheek depth (16 – 17 % versus 18 – 29 % HL), fewer teeth on the left lower jaw (11 –

12 versus 13 – 14) and fewer dorsal spines (15 – 16 versus 17 – 18) M. formosus. Mylochromis ericotaenia has a smaller cheek depth (16 – 17 % versus 18 – 32 % HL), fewer dorsal rays (11 versus 12), fewer cheek scales (2 versus 4 – 5) and fewer anal rays (7 – 8 versus 9) than M. gracilis. Mylochromis ericotaenia has a shorter snout length (27 – 29 % versus 31 % HL), a smaller cheek depth (16 – 17 % versus 23 % HL) and a smaller head depth (53 – 60 % versus 65

% HL), more dorsal rays (11 versus 10), less cheek scales (2 versus 3) and more teeth rows on the lower jaw (4 versus 2) than M. guentheri. Mylochromis ericotaenia has a longer post dorsal

58 to post anal length (12 – 15 % versus 11 % SL), a smaller cheek depth (16 – 17 % versus 23 %

HL) and longer post dorsal to ventral caudal length (18 – 21 % versus 17 % SL), fewer cheek scales (2 versus 3) and more teeth rows on the lower jaw (4 versus 2) than M. labidodon.

Description

Morphometric and meristic data in Table 9. Blotched diagonal stripe along the side of the body. Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 15 – 16 spines and 11 dorsal rays. Anal fin with 3 spines and 7 - 8 anal rays. Lateral lines scales 31 with no pored scales. Gill rakers on first ceratobranchial 8 - 9 and on first epibranchial 4.

Females and immature males silvery, darker brown dorsally (Turner 1996). Non-breeding individuals with pigmentation pattern consisting of four to eight vertical bars, some or all of which with dark blotches in diagonal series. Rarely, and then only in juveniles, the spots in almost solid line. Large males with slight nuchal hump and a somewhat longer snout. Breeding males blue (Konings 2007).

Field observations: Not recorded.

Distribution

Mylochromis ericotaenia is found in low sandy habitat all around the lake. It is rare in most places, but common at Hai Reef in Tanzania and at Chiwindi in Mozambique (Konings 2007).

Table 9. Morphometric and meristic values of Mylochromis ensatus (n = 10), Mylochromis

epicholiaris (n = 2) and Mylochromis ericotaenia (n = 2)

M. ensatus M. epicholiaris M. ericotaenia

(n = 10) (n = 2) (n = 2)

range range

Standard length, mm 92.1 – 203.4 166.2 – 166.5 50.5 – 57.1

Head length, mm 25.2 – 59.7 64.3 – 64.8 16.7 – 16.9

Percent standard length

Head length 27 – 31 39 30 – 33

Snout to dorsal-fin origin 30 – 33 42 32 – 44

Snout to pelvic-fin origin 33 – 38 44 37

Dorsal-fin base length 55 – 57 50 – 51 51 – 53

Anterior dorsal to anterior anal 41 – 45 45 – 46 40 – 44

Anterior dorsal to posterior anal 56 – 58 54 – 55 53 – 57

Posterior dorsal to anterior anal 27 – 29 28 24 – 27

Posterior dorsal to posterior anal 12 – 14 13 12 – 15

Posterior dorsal to ventral caudal 16 – 20 17 – 19 18 – 21

Posterior anal to dorsal caudal 18 – 21 19 – 22 20

Anterior dorsal to pelvic-fin origin 26 – 29 35 – 37 27 – 28

Posterior dorsal to pelvic-fin origin 52 – 54 48 – 51 48 – 50

Caudal-peduncle length 18 – 20 18 – 20 19 – 20

Least caudal-peduncle depth 9 – 10 11 – 12 10

Body depth 23 – 28 36 – 37 25 – 28

Percent head length

Snout length 33 – 34 34 – 35 27 – 29

Postorbital head length 37 – 41 35 – 36 40

Horizontal eye diameter 25 – 32 25 – 26 34 – 39

Vertical eye diameter 22 – 30 25 34 – 38

Preorbital length 28 – 36 44 – 45 21 – 33

Cheek depth 15 – 23 23 – 24 16 – 17

Lower-jaw length 32 – 38 35 26 – 31

Head depth 53 – 70 61 – 69 53 – 60

Counts

Dorsal-fin spines 16 – 17 16 15 – 16

Dorsal-fin rays 11 – 13 10 – 11 11

Anal-fin spines 3 3 3

Anal-fin rays 9 8 7 – 8

Pectoral-fin rays 13 – 14 12 – 14 12 – 13

Pelvic-fin rays 5 5 5

Lateral-line scales 34 – 37 32 31

Pored scales posterior of lateral line 0 – 1 0 0

Scale rows on cheek 3 – 4 4 – 5 2

Gill rakers on first ceratobranchial 11 – 14 10 8 – 9

Gill rakers on first epibranchial 4 4 4

Teeth in outer row of left lower jaw 11 – 26 8 – 10 11 – 12

Teeth rows on upper jaw 4 – 7 2 – 4 3 – 4

Teeth rows on lower jaw 4 – 6 4 - 5 4

8. Mylochromis formosus (Trewavas 1935)

Figure 19. Mylochromis formosus (Trewavas), Lectotype, 98 mm standard length. Source: Eccles and Trewavas.

Material examined

BMNH1935.6.14.1454-1455; lectotype and paralectotype; 2; 97.3 – 102.9 mm; Vua, Lake

Malaŵi; 18th April 1905.

Diagnosis

Mylochromis formosus along with Mylochromis chepokae, Mylochromis ensatus,

Mylochromis ericotaenia, Mylochromis gracilis, Mylochromis guentheri and Mylochromis labidodon have a snout to dorsal fin origin length of less than 35 % of the standard length and a snout length of greater than 25 % head length.

Mylochromis formosus has a smaller head depth (54 – 56 % versus 65 – 90 % HL), fewer gill rakers on the first ceratobranchial (9 versus 12 – 16), fewer dorsal rays (11 versus 12 – 13) and fewer cheek scales (2 versus 3 – 4) than M. chepokae. Mylochromis formosus has a shorter preorbital head length (24 – 25 % versus 28 – 36 % HL) and a longer least caudal peduncle depth

(11 % versus 9 – 10 % SL), fewer cheek scales (2 versus 3 – 4) and fewer gill rakers on the first ceratobranchial (9 versus 11 – 14) than M. ensatus. Mylochromis formosus has a larger cheek depth (18 – 29 % versus 16 – 17 % HL), more teeth on the left lower jaw (13 – 14 versus 11 –

12) and more dorsal spines (17 – 18 versus 15 – 16) than M. ericotaenia. Mylochromis formosus has a shorter snout to pelvic fin origin length (36 % versus 37 – 39 % SL), fewer dorsal rays (11 versus 12) and fewer cheek scales (2 versus 4 – 5) than M. gracilis. Mylochromis formosus has a longer snout length (32 – 34 % versus 31 % HL), a smaller cheek depth (18 – 20 % versus 23 %

HL) and a longer preorbital head length (24 – 25 % versus 22 % HL), more teeth rows on the lower jaw (4 versus 2), more dorsal rays (11 versus 10) and fewer cheek scales (2 versus 3) than

M. guentheri. Mylochromis formosus has a smaller head depth (54 – 56 % versus 64 – 83 % HL) and fewer gill rakers on the first ceratobranchial (9 versus 10 – 11) than M. labidodon.

Description

Morphometric and meristic data in Table 10. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 17 – 18 spines and 11 dorsal rays. Anal fin with 3 spines and 8 -

9 anal rays. Lateral lines scales 31 - 35 with no pored scales. Gill rakers on first ceratobranchial 9 and on first epibranchial 4.

Females and immature males yellowish with broad continuous black oblique band and continuous black stripe on preorbital bone (Turner 1996).

Field observations

Mylochromis formosus is one of the elongate predators. It is sometimes caught in beach seines that are dragged over the sand. Underwater observations indicate that most juveniles live in the intermediate habitat where they hunt for small fishes. The species occurs in shallow water, usually no deeper than 15 meters (Konings 2007).

9. Mylochromis gracilis (Trewavas 1935)

Figure 20. Mylochromis gracilis (Trewavas). Lectotype, male, 174 mm standard length. Source: Eccles and Trewavas (1989).

Material examined

BMNH1935.6.14.1456-1458; 3; 174.2 – 176.8 mm SL; Monkey Bay, Lake Malaŵi.

Diagnosis

Mylochromis gracilis along with Mylochromis chekopae, Mylochromis ensatus, Mylochromis ericotaenia, Mylochromis formosus, Mylochromis guentheri and Mylochromis labidodon have a snout to dorsal fin origin length of less than 35 % of the standard length and a snout length of greater than 25 % head length.

Mylochromis gracilis has a smaller head depth (49 – 55 % versus 65 – 90 % HL) and a longer preorbital head length (34 – 36 % versus 22 – 29 % HL) than M. chepokae. Mylochromis gracilis has a shorter snout length (28 – 30 % versus 33 – 34 % HL) and fewer teeth rows on upper jaw (3 versus 4 – 7) than M. chepokae. Mylochromis gracilis has a larger cheek depth (18

– 32 % versus 16 – 17 % HL), more dorsal rays (12 versus 11), more cheek scales (4 – 5 versus

2) and more anal rays (9 versus 7 – 8) than M. ericotaenia. Mylochromis gracilis has a longer snout to pelvic fin origin length (37 – 39 % versus 36 % SL), more dorsal rays (12 versus 11) and more cheek scales (4 – 5 versus 2) than M. formosus. Mylochromis gracilis has a longer preorbital head length (34 – 36 % versus 32 % HL) and a smaller horizontal eye diameter (25 –

28 % versus 40 % HL), more cheek scales (4 – 5 versus 3), more teeth rows on the lower jaw (4 -

5 versus 2) and more dorsal rays (12 versus 10) than M. guentheri. Mylochromis gracilis has a smaller body depth (49 – 55 % versus 64 – 83 % HL), a shorter snout length (28 – 30 % versus

32 – 41 % HL), a longer post orbital head length (41 – 44 % versus 36 – 40 % HL), a smaller

66 body depth (24 – 26 % versus 27 – 32 % SL), more cheek scales (4 -5 versus 2 -3) and more dorsal rays (12 versus 10 – 11) than M. labidodon.

Description

Morphometric and meristic data in Table 10. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 17 spines and 12 dorsal rays. Anal fin with 3 spines and 9 anal rays. Lateral lines scales 34 - 38 with 0 - 1 pored scales (mode 0). Gill rakers on first ceratobranchial 9 – 12 and on first epibranchial 4 – 5 (mode 4).

Females and immature males yellowish, paler ventrally. Dorsal and caudal fins faintly spotted. Ripe males with blue head and dorsum with numerous yellow spots on flanks. Belly yellow. Black stripe on preorbital bone and the chin and chest black. Caudal blue with yellow spots and stripes. Dorsal fin white with yellow spots with white border, yellow tips to the lappets, and black submarginal band on anterior half. Anal fin black with broad white margin and numerous small white egg-spots. Pelvics with black leading edge (Turner 1996).

Field observations

Mylochromis gracilis has a large mouth which together with its teeth and its shape suggests a predatory lifestyle. It has been observed hunting the shell-dwelling Metriaclima lanisticola, during which the mouth is “fired” into the shell. Sexually active males defend a territory and construct a sand castle with a diameter of about 50 cm. the eggs are very small and are fertilized inside the female‟s mouth. Juveniles are very small and slim in comparison to those of other predators of similar size (Konings 2007).

Distribution

The distribution of this rare species seems to be restricted to the southern part of the lake

(Konings 2007).

10. Mylochromis guentheri (Regan 1922)

Figure 21. Mylochromis guentheri (Regan). Holotype, 153 mm standard length. Source: Eccles and Trewavas (1989).

Material examined

BMNH1908.10.27.85; holotype; 1; 61.3 mm SL; Lake Malaŵi; 5th April 1905.

Diagnosis

Mylochromis guentheri along with Mylochromis chekopae, Mylochromis ensatus,

Mylochromis ericotaenia, Mylochromis formosus, Mylochromis gracilis and Mylochromis labidodon has a snout to dorsal fin length of less than 35 % of the standard length and a snout length of greater than 25 % head length.

Mylochromis guentheri has fewer gill rakers on the first ceratobranchial (9 versus 12 – 16) and fewer dorsal rays (10 versus 12 – 13) than M. chekopae. Mylochromis guentheri has a shorter post dorsal to anterior anal length (25 % versus 27 – 29 % SL), fewer anal rays (8 versus

9), fewer dorsal rays (10 versus 11 – 13), fewer teeth rows on lower jaw (2 versus 4 – 6) and fewer gill rakers on the first ceratobranchial (9 versus 11 – 14) than M. chekopae. Mylochromis guentheri has a longer snout length (31 versus 27 – 29 % HL), a larger cheek depth (23 % versus

16 – 17 % HL), a larger head depth (65 % versus 53 – 60 % HL), fewer dorsal rays (10 versus

11), more cheek scales (3 versus 2) and fewer teeth rows on the lower jaw (2 versus 4) than M. ericotaenia. Mylochromis guentheri has a shorter snout length (31 versus 32 – 34 % HL), a larger cheek depth (23 % versus 18 – 20 % HL) a shorter preorbital head length (22 % versus 24

– 25 % HL), fewer teeth rows on the lower jaw (2 versus 4), fewer dorsal rays (10 versus 11) and more cheek scales (3 versus 2) than M. formosus. Mylochromis guentheri has a shorter preorbital head length (32 % versus 34 – 36 % HL), a larger horizontal eye diameter (40 % versus 25 – 28

% HL), fewer cheek scales (3 versus 4 – 5), fewer teeth rows on the lower jaw (2 versus 4 -5) and fewer dorsal rays (10 versus 12) than M. gracilis. Mylochromis guentheri has a shorter posterior dorsal to posterior anal length (11 % versus 13 – 15 % SL) and a shorter posterior dorsal to ventral caudal length (17 versus 19 – 21 % SL), fewer gill rakers on the first

69 ceratobranchial (9 versus 10 – 11), fewer teeth on the left lower jaw (7 versus 10 – 13) and fewer teeth rows on the lower jaw (2 versus 4 – 6) than M. labidodon.

Description

Morphometric and meristic data in Table 10. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 16 spines and 10 dorsal rays. Anal fin with 3 spines and 8 anal rays. Lateral lines scales 33 with no pored scales. Gill rakers on first ceratobranchial 9 and on first epibranchial 4.

Color description not available for live specimens.

Field observations

Mails build bowers using a rock as part of the construction and the bowers are between 5 to

10 meters apart. Mouthbrooding females are solitary and often rest on the sand of the intermediate habitat (Konings 2007).

Distribution

The species appears to have a lake-wide distribution but is nowhere common (Konings

2007).

Table 10. Morphometric and meristic values of Mylochromis formosus (n = 2), Mylochromis

gracilis (n = 3) and Mylochromis guentheri (n = 1)

M. formosus M. gracilis M. guentheri

(n = 2) (n = 3) (n = 1)

range range

Standard length, mm 97.3 – 102.9 174.2 – 176.8 61.3

Head length, mm 29.1 – 30.4 53.7 – 56.0 18.0

Percent standard length

Head length 30 31 – 32 29

Snout to dorsal-fin origin 33 32 – 34 33

Snout to pelvic-fin origin 36 37 – 39 35

Dorsal-fin base length 56 – 58 55 – 57 42

Anterior dorsal to anterior anal 44 – 46 44 – 45 45

Anterior dorsal to posterior anal 58 – 61 57 – 58 56

Posterior dorsal to anterior anal 26 – 28 27 – 28 25

Posterior dorsal to posterior anal 13 – 14 12 – 15 11

Posterior dorsal to ventral caudal 17 – 18 17 – 18 17

Posterior anal to dorsal caudal 21 21 – 22 19

Anterior dorsal to pelvic-fin origin 27 – 28 26 – 28 30

Posterior dorsal to pelvic-fin origin 51 – 53 50 – 52 50

Caudal-peduncle length 18 – 20 19 – 21 20

Least caudal-peduncle depth 11 9 – 10 9

Body depth 26 – 27 24 – 26 28

Percent head length

Snout length 32 – 34 28 – 30 31

Postorbital head length 39 – 40 41 – 44 37

Horizontal eye diameter 31 25 – 28 40

Vertical eye diameter 28 – 30 21 – 22 36

Preorbital length 24 – 25 34 – 36 22

Cheek depth 18 – 20 18 – 32 23

Lower-jaw length 34 – 35 37 – 39 36

Head depth 54 – 56 49 – 55 65

Counts

Dorsal-fin spines 17 – 18 17 16

Dorsal-fin rays 11 12 10

Anal-fin spines 3 3 3

Anal-fin rays 8 – 9 9 8

Pectoral-fin rays 13 13 12

Pelvic-fin rays 5 5 5

Lateral-line scales 31 – 35 34 – 38 33

Pored scales posterior of lateral line 0 0 – 1 0

Scale rows on cheek 2 4 – 5 3

Gill rakers on first ceratobranchial 9 9 – 12 9

Gill rakers on first epibranchial 4 4 – 5 4

Teeth in outer row of left lower jaw 13 – 14 23 – 25 7

Teeth rows on upper jaw 3 – 4 3 3

Teeth rows on lower jaw 4 4 - 5 2

11. Mylochromis incola (Trewavas 1935)

Figure 22. Mylochromis incola (Trewavas). Lectotype, male, 97 mm standard length. Source: Eccles and Trewavas (1989).

Material examined

BMNH1935.6.14.2341-2347; syntypes; 9; 89.3 – 141.8 mm SL; Lake Malaŵi, Mangochi.

Diagnosis

Mylochromis incola along with Mylochromis balteatus, Mylochromis lateristriga,

Mylochromis incola has a longer snout to pelvic fin origin length (42 – 47 % versus 39 – 41

% SL) than M. balteatus. Mylochromis incola has a longer snout length (39 – 46 % versus 31 –

40 % HL), a shorter dorsal fin base length (48 – 52 % versus 51 – 56 % SL) and a shorter horizontal eye diameter (28 – 33 % versus 26 – 40 % HL) than M. lateristriga. Mylochromis incola has a longer preorbital head length (30 – 33 % versus 26 – 27 % HL) and more dorsal rays

(10 – 11 versus 9 – 10) than M. melanotaenia. Mylochromis incola has a shorter dorsal fin base length (48 – 52 % versus 53 – 55 % SL) and a shorter posterior dorsal to posterior anal length

(12 – 14 % versus 15 – 16 % SL) than M. mola. Mylochromis incola has a longer snout length

(39 – 46 % versus 35 – 36 % HL), a shorter posterior dorsal to posterior anal length (12 – 14 % versus 15 % SL) and a shorter dorsal fin base length (48 – 52 % versus 54 – 55 % SL) than M. sphaerodon. Mylochromis incola has more pectoral rays (14 – 15 versus 10 – 13) than M. subocularis.

Description

Morphometric and meristic data in Table 11. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 15 - 16 spines (mode 16) and 10 - 11 dorsal rays (mode 10). Anal fin with 3 spines and 8 - 9 anal rays (mode 8). Lateral lines scales 30 - 33 (mode 31, 32) with 0 -

1 pored scales (mode 0). Gill rakers on first ceratobranchial 8 – 10 (mode 9) and on first epibranchial 2 – 4 (mode 3).

Color description not available for live specimens.

Field observations

Mylochromis incola is an invertebrate feeder and is found mainly among Vallisneria beds. It picks insects and crustaceans from among the plants. Bower building has been observed in the population at Nankoma Island where males construct the spawning pit beneath a small, overhanging rock (Konings 2007).

Distribution

Mylochromis incola has a lake-wide distribution (Konings 2007).

Discussion

Although there was an overlap between the character states of Mylochromis incola and

Mylochromis lateristriga, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 23).

M. incola M. lateristriga

0.10

)

a d

0.05

m o

h 0.00

(

2 -0.05

D R

H -0.10 S

-0.15 -2 -1 0 1 2 PCA1 (meristic data)

Figure 23. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. incola and M. lateristriga.

12. Mylochromis labidodon (Trewavas 1935)

Figure 24. Mylochromis labidodon (Trewavas). Lectotype, female, 99 mm standard length. Source: Eccles and Trewavas (1989).

Material examined

BMNH1935.6.14.2416-2419; 4; 83.4 – 150.1 mm; Lake Malaŵi, Mwaya and Deep Bay.

Diagnosis

Mylochromis labidodon along with Mylochromis chekopae, Mylochromis ensatus,

Mylochromis ericotaenia, Mylochromis formosus, Mylochromis gracilis, and Mylochromis guentheri has a snout to dorsal fin origin length of less than 35 % of the standard length and a snout length of greater than 25 % head length.

Mylochromis labidodon has a shorter posterior dorsal to anterior anal length (26 – 28 % versus 29 – 33 % SL), fewer dorsal rays (10 – 11 versus 12 -13), fewer gill rakers on the first ceratobranchial (9 versus 12 – 16) and fewer dorsal rays (10 – 11 versus 12 – 13) than M. chepokae. Mylochromis labidodon has more anal rays (10 – 11 versus 9) than M. ensatus.

Mylochromis labidodon has a shorter posterior dorsal to posterior anal length (11 % versus 12 –

15 % SL), a larger cheek depth (23 % versus 16 – 17 % HL), shorter posterior dorsal to ventral caudal length (17 % versus 18 – 21 % SL), more cheek scales (3 versus 2) and fewer teeth rows on the lower jaw (2 versus 4) than M. ericotaenia. Mylochromis labidodon has a larger head depth (64 – 83 % versus 54 – 56 % HL) and more gill rakers on the first ceratobranchial (10 – 11 versus 9) than M. formosus. Mylochromis labidodon has a larger body depth (64 – 83 % versus

49 – 55 % HL), a longer snout length (32 – 41 % versus 28 – 30 % HL), a shorter postorbital head length (36 – 40 % versus 41 – 44 % HL), a deeper body depth (27 – 32 % versus 24 – 26 %

SL), fewer cheek scales (2 – 3 versus 4 -5) and fewer dorsal rays (10 – 11 versus 12) than M. formosus. Mylochromis labidodon has a longer posterior dorsal to posterior anal length (13 – 15

% versus 11 % SL), a longer posterior dorsal to ventral caudal length (19 – 21 % versus 17 %

SL), more gill rakers on the first ceratobranchial (10 – 11 versus 9), more teeth on the left lower jaw (10 – 13 versus 7) and more teeth rows on the lower jaw (4 – 6 versus 2) than M. guentheri.

Description

Morphometric and meristic data in Table 11. Blotched diagonal stripe along the side of the body. Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 16 - 17 spines (mode 16) and 10 - 11 dorsal rays (mode 11).

Anal fin with 3 spines and 7 - 8 anal rays (mode 8). Lateral lines scales 31 - 33 (mode 31) with 0

- 2 pored scales (mode 1). Gill rakers on first ceratobranchial 10 – 11 (mode 11) and on first epibranchial 4.

Mylochromis labidodon with very silvery body with broad vertical bars and a very thin red edge to the dorsal fin. The characteristic strip of Mylochromis absent, except in northern populations. Northern populations with interrupted diagonal stripe; adults in southern populations with pattern of vertical bars, and juveniles with incomplete diagonal line (Konings

2007).

Field observations

Mylochromis labidodon prefers mixed and sandy regions ranging from shallow water to depths about 15 meters. Young and sub-adults (total length about 7 to 9 cm) are frequently found in small groups of three to eight individuals. Sexually mature males and females are solitary.

This species is not territorial and seemingly roams aimlessly through the underwater scenery

(Spreinat 1995). This species is common over pebble beds where it turns over any small stone it can grasp with its mouth. When it finds anything palatable beneath the stone, it quickly dives into the rubble to seize it (Konings 2007).

Distribution

It is probably widely distributed in the lake (Konings 2007 and Spreinat 1995).

Table 11. Morphometric and meristic values of Mylochromis incola (n = 9), Mylochromis

labidodon (n = 4) and Mylochromis lateristriga (n = 16)

M. incola M. labidodon M. lateristriga

(n = 9) (n = 4) (n = 16)

range range range

Standard length, mm 89.3 – 141.8 83.4 – 150.1 54.4 – 153.9

Head length, mm 33.2 – 47.7 25.4 – 45.2 18.3 – 46.4

Percent standard length

Head length 33.2 – 47.7 30 – 31 30 – 35

Snout to dorsal-fin origin 37 – 42 33 – 34 35 – 40

Snout to pelvic-fin origin 42 – 47 37 – 39 35 – 41

Dorsal-fin base length 48 – 52 53 – 58 51 – 56

Anterior dorsal to anterior anal 45 – 47 45 – 47 44 – 52

Anterior dorsal to posterior anal 54 – 56 56 – 59 55 – 62

Posterior dorsal to anterior anal 27 – 29 26 – 28 25 – 29

Posterior dorsal to posterior anal 12 – 14 13 – 15 11 – 15

Posterior dorsal to ventral caudal 17 – 19 19 – 21 17 – 20

Posterior anal to dorsal caudal 19 – 21 19 – 22 18 – 21

Anterior dorsal to pelvic-fin origin 34 – 38 29 – 33 31 – 36

Posterior dorsal to pelvic-fin origin 47 – 50 49 – 53 48 – 52

Caudal-peduncle length 17 – 20 18 – 21 18 – 20

Least caudal-peduncle depth 10 – 12 10 – 11 9 – 12

Body depth 32 – 36 27 – 32 29 – 34

Percent head length

Snout length 39 – 46 32 – 41 31 – 41

Postorbital head length 33 – 44 36 – 40 34 – 41

Horizontal eye diameter 28 – 33 28 – 34 26 – 40

Vertical eye diameter 25 – 30 27 – 33 26 – 39

Preorbital length 30 – 33 23 – 32 23 – 35

Cheek depth 18 – 23 19 – 24 18 – 26

Lower-jaw length 31 – 35 32 – 40 30 – 38

Head depth 63 – 74 64 – 83 55 – 81

Counts

Dorsal-fin spines 15 – 16 16 – 17 15 – 16

Dorsal-fin rays 10 – 11 10 – 11 10 – 12

Anal-fin spines 3 3 3

Anal-fin rays 8 – 9 7 – 8 7 – 9

Pectoral-fin rays 14 – 15 11 – 14 11 – 14

Pelvic-fin rays 5 5 5

Lateral-line scales 30 – 33 31 – 33 26 – 32

Pored scales posterior of lateral line 0 – 2 0 – 2 0 – 1

Scale rows on cheek 3 – 4 2 – 3 2 – 4

Gill rakers on first ceratobranchial 8 – 10 10 – 11 8 – 12

Gill rakers on first epibranchial 2 – 4 4 3 – 4

Teeth in outer row of left lower jaw 11 – 23 10 – 13 11 – 16

Teeth rows on upper jaw 3 – 6 3 – 5 3 – 6

Teeth rows on lower jaw 3 – 5 4 – 6 2 – 7

13. Mylochromis melanonotus (Regan 1922)

Figure 25. Mylochromis melanonotus (Regan). Source: Konings 2007.

Material examined

BMHN1921.9.6.163-164; lectotype; 1; 171.5 mm SL; Lake Malaŵi

Diagnosis

Mylochromis melanonotus along with Mylochromis semipalatus have a snout to dorsal fin origin length greater than 35 % of the standard length, a preorbital head length of less than 40 % head length and 18 dorsal spines, which distinguishes them from all other Mylochromis.

Mylochromis melanonotus has a shorter snout length (31 % versus 40 – 41 % % HL) and a longer preorbital head length (39 % versus 30 – 33 % HL) than M. semipalatus. Meristically, M. melanonotus has fewer anal rays (8 versus 9), fewer teeth rows on upper jaw (3 versus 4 – 5) and fewer teeth rows on lower jaw (3 versus 5) than M. semipalatus.

Description

Morphometric and meristic data in Table 12. Solid diagonal stripe along the side of body.

Dorsal body profile with downward curve to caudal peduncle; ventral body profile convex.

Tapering Dorsal head profile convex. Dorsal fin with 18 spines and 10 dorsal rays. Anal fin with

3 spines and 8 anal rays. Lateral lines scales 35 with 1 pored scale. Gill rakers on first ceratobranchial 11 and on first epibranchial 4.

Breeding males completely blue with no diagonal stripe. Eight to nine vertical bars on the flanks of territorial males (Konings 2007). Females and immature males bright yellowish, more intense ventrally with prominent black oblique stripe (Turner 1996).

Field observations

Mylochromis melanonotus is occasionally attracted to large black catfishes. It has been observed attacking a breeding pair of Bagrus meridionalis and trying to snatch fry out of the nest. Males defend spawning sites between rocks in the intermediate habitat or may defend craters in the sand. The eggs are fertilized inside the female‟s mouth (Konings 2007).

14. Mylochromis melanotaenia (Regan 1922)

Figure 26. Mylochromis melanotaenia (Regan), Lectotype, male, 143 mm standard length. Source: Eccles and Trewavas (1989).

Material examined

BMNH1921.9.6.151-153; 3; 101.4 – 142.6 mm SL; Lake Malaŵi; 4th May 1905.

Diagnosis

Mylochromis melanotaenia along with Mylochromis balteatus, Mylochromis incola,

Mylochromis lateristriga, Mylochromis mola, Mylochromis sphaerodon and Mylochromis subocularis has a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than 40 % and dorsal spines less than 17.

Mylochromis melanotaenia has a shorter preorbital head length (26 – 27 % versus 29 – 35 %

HL) and (10 – 12 versus 13 – 15) than M. balteatus. Mylochromis melanotaenia has a shorter preorbital head length (26 – 27 % versus 30 – 33 % HL) than M. incola. There is a lot of overlap in both morphometric measurements and meristic counts between M. melanotaenia and M. lateristriga. Mylochromis melanotaenia has more lateral line scales (31 – 32 versus 26 – 32) and more cheek scales (4 versus 2 – 4) than M. lateristriga. Mylochromis melanotaenia has a shorter preorbital head length (26 – 27 % versus 31 – 34 % HL) and a shorter posterior dorsal to posterior anal length (13 – 14 % versus 15 – 16 % SL) than M. mola. Mylochromis melanotaenia has a shorter preorbital head length (26 – 27 % versus 31 – 32 % HL) and a larger body depth

(66 – 71 % versus 62 – 65 % HL), more cheek scales (4 versus 2 – 3) and fewer teeth on the left lower jaw (4 versus 2 – 3) than M. sphaerodon. Mylochromis melanotaenia has more anal rays (9

– 10 versus 7 – 8) than M. subocularis.

Description

Morphometric and meristic data in Table 12. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 15 - 16 spines (mode 16) and 9 - 10 dorsal rays (mode 10). Anal fin with 3 spines and 8 – 9 anal rays (mode 8). Lateral lines scales 31 - 32 (mode 32) with 0 - 1 pored scale (mode 0). Gill rakers on first ceratobranchial 9 and on first epibranchial 4.

Females and immature silvery with prominent black oblique stripe (Turner 1996). Breeding males of Mylochromis melanotaenia mainly steel blue, with a yellowish tail. (Konings 2007).

Field observations

Mylochromis melanotaenia continually digs and filters the sand for anything palatable; it is characterized by stout teeth on the pharyngeals and thick lips, which suggests that it may suck snails out of their shells. It is generally found on muddy bottoms near river outlets at depths varying between 15 and 40 meters (Konings 2007).

Distribution

Mylochromis melanotaenia has been found in the south and along the eastern shores, and also at Makonde in northern section of the lake (Konings 2007).

Discussion

Although there was an overlap between the character states of M. melanotaenia and M. lateristriga, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 27).

Figure 27. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. melanotaenia and M. lateristriga.

15. Mylochromis mola (Trewavas 1935)

Figure 28. Mylochromis mola (Trewavas). Lectotype, male, 139 mm standard length. Sources: Eccles and Trewavas.

Material examined

BMNH1935.14.2357-2359; syntypes; 3; 110 – 140 mm SL; Lake Malaŵi, Vua.

Diagnosis

Mylochromis mola along with Mylochromis balteatus, Mylochromis incola, Mylochromis lateristriga, Mylochromis melanotaenia, Mylochromis sphaerodon and Mylochromis subocularis

90 has a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than

40 % and dorsal spines less than 17.

Mylochromis mola has a longer snout to pelvic fin origin length (42 – 43 % versus 39 – 41 %

SL), more teeth rows on lower jaw (6 versus 4) and more teeth rows on upper jaw (6 versus 3 –

5) than M. balteatus. Mylochromis mola has a longer dorsal fin base length (53 – 55 % versus 48

– 52 % SL) and a longer posterior dorsal to posterior anal length (15 – 16 % versus 12 – 14 SL) than M. incola. There is a lot of overlap in both morphometric measurements and meristic counts between M. mola and M. lateristriga. Mylochromis mola has a longer snout length (38 – 44 % versus 31 – 40 % HL) than M. lateristriga. Mylochromis mola has a longer preorbital head length

(31 – 34 % versus 26 – 27 % HL) and a longer posterior dorsal to posterior anal length (15 – 16 versus 13 – 14 % SL) than M. melanotaenia. Mylochromis mola has more teeth rows on the lower jaw (6 versus 5) than M. sphaerodon. Mylochromis mola has more teeth rows on upper jaw

(6 versus 2 – 4) and more pectoral rays (14 versus 10 – 13) than M. subocularis.

Description

Morphometric and meristic data in Table 12. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 16 spines and 10 - 11 dorsal rays (mode 11). Anal fin with 3 spines and 8 – 9 anal rays (mode 9). Lateral lines scales 30 - 32 with no pored scale. Gill rakers on first ceratobranchial 9 – 10 (mode 10) and on first epibranchial 3 – 4 (mode 4).

Mylochromis mola silvery white body with diagonal row of large black blotches, and, in the northern populations, orange anal and pelvic fins. The orange color weak in the southern

91 populations and all fins hyaline. Breeding color of males blue, and no diagonal stripe (Konings

2007).

Field observations

Territorial males of M. mola defend a small area in the rubble of the intermediate habitat. A bower is not constructed but a spawning patch is cleared of irregularities (Konings 2007).

Distribution

Mylochromis mola is frequently seen at many different locations around the lake, in the northern as well as the southern part (Konings 2007). Very probably, it has a lakewide distribution (Spreinat 1995).

Discussion

Although there was an overlap between the character states of M. mola and M. lateristriga, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 29).

Figure 29. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mola and M. lateristriga.

Table 12. Morphometric and meristic values of Mylochromis melanonotus (n = 1), Mylochromis

melanotaenia (n = 3) and Mylochromis mola (n = 3)

M. melanonotus M. melanotaenia M. mola

(n = 1) (n = 3) (n = 3)

range

Standard length, mm 171.5 101.4 – 142.6 110 – 140

Head length, mm 54.8 35 – 51 39.2 – 44.6

Percent standard length

Head length 32 35 - 36 32 – 36

Snout to dorsal-fin origin 36 41 – 43 39 – 40

Snout to pelvic-fin origin 42 41 – 42 42 – 43

Dorsal-fin base length 53 51 – 53 53 – 55

Anterior dorsal to anterior anal 49 46 – 48 48 – 50

Anterior dorsal to posterior anal 58 57 58 – 59

Posterior dorsal to anterior anal 29 27 – 29 29

Posterior dorsal to posterior anal 15 13 – 14 15 – 16

Posterior dorsal to ventral caudal 20 20 18 – 19

Posterior anal to dorsal caudal 21 21 – 22 20

Anterior dorsal to pelvic-fin origin 37 36 – 39 36 – 38

Posterior dorsal to pelvic-fin origin 50 49 – 52 49 – 51

Caudal-peduncle length 19 19 – 20 18 – 20

Least caudal-peduncle depth 11 11 11 – 12

Body depth 37 35 – 38 35 – 37

Percent head length

Snout length 31 37 – 39 38 – 44

Postorbital head length 39 34 – 39 34 – 38

Horizontal eye diameter 27 31 – 36 30 – 33

Vertical eye diameter 24 28 – 36 29 – 33

Preorbital length 39 26 – 27 31 – 34

Cheek depth 25 23 – 27 21 – 23

Lower-jaw length 38 35 – 38 32 – 38

Head depth 72 66 – 71 63 – 77

Counts

Dorsal-fin spines 18 15 – 16 16

Dorsal-fin rays 10 9 – 10 10 – 11

Anal-fin spines 3 3 3

Anal-fin rays 8 8 – 9 8 – 9

Pectoral-fin rays 14 14 – 15 14

Pelvic-fin rays 5 5 5

Lateral-line scales 35 31 – 32 30 – 32

Pored scales posterior of lateral line 1 0 – 1 0

Scale rows on cheek 4 4 3 – 4

Gill rakers on first ceratobranchial 11 9 9 – 10

Gill rakers on first epibranchial 4 4 3 – 4

Teeth in outer row of left lower jaw 24 10 – 12 17 – 21

Teeth rows on upper jaw 3 4 – 6 6

Teeth rows on lower jaw 3 4 – 5 6

16. Mylochromis mollis (Trewavas 1935)

Figure 30. Mylochromis mollis (Trewavas). Holotype, 133 mm standard length. Sources: Eccles and Trewavas (1989).

Material examined

BMNH1935.6.14.1334, 2, Paralectotype 85.7mm SL and Lectotype 132.3 mm SL, Monkey

Bay and South West arm of Lake Malaŵi.

Diagnosis

Mylochromis mollis can be distinguished from all members of this genus by a snout to dorsal fin origin length of greater than 35 % SL, a preorbital head length of less than 40 % HL, less than

17 dorsal spines and more than 12 gill rakers on the first ceratobranchial.

Description:

See Table 8 for morphometric and meristic data in Table 13. Solid diagonal stripe along the side of the body. Dorsal body profile downward to caudal peduncle; ventral body profile convex.

Dorsal head profile convex. Dorsal fin with 16 – 17 spines and 11 dorsal rays. Anal fin with 3 spines and 8. Lateral lines scales 31 - 33 with 0 - 1 pored scale. Gill rakers on first ceratobranchial 13 – 15 and on first epibranchial 3 – 4.

Color description not available for live specimens.

Field observations: Not recorded.

17. Mylochromis obtusus (Trewavas 1935)

Figure 31. Mylochromis obtusus (Trewavas). Holotype, 190 mm standard length. Source: Eccles and Trewavas (1989).

Material examined

BMNH1935.6.14.1453; holotype; 1; 188.5 mm SL; Bar-Nkuzi, Lake Malaŵi.

Diagnosis

Mylochromis obtusus along with Mylochromis epicholiaris has a snout to dorsal fin origin length of more than 35 % of head length and a preorbital head length of more than 40 % of head length. M. obtusus has a larger head depth (81 % versus 61 – 69 % HL) and a longer anterior

99 dorsal to anterior anal length (52 % versus 45 – 46 % SL) than M. epicholiaris. Meristically, M. obtusus has fewer dorsal spines (16 versus 17) and more gill rakers on the first ceratobranchial

(12 versus 10) than M. epicholiaris.

Description

Morphometric and meristic data in Table 13. Solid diagonal stripe along side of body. Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 17 spines and 10 dorsal rays. Anal fin with 3 spines and 9 anal rays.

Lateral lines scales 32 with no pored scale. Gill rakers on first ceratobranchial 12 (mode 10) and on first epibranchial 3.

Breeding males with blue color on silvery body (Konings 2007).

Field observations

Aquarium observations show that Mylochromis obtusus eats eggs of other cichlids (Konings

2007).

100

18. Mylochromis semipalatus (Trewavas 1935)

Figure 32. Mylochromis semipalatus (Trewavas). Lectotype, female, 141 mm standard length. Source: Eccles and Trewavas (1989).

Material examined

BMNH1935.6.14.1321-1323; syntypes; 2, 140.5 – 148.1 mm SL; Deep Bay and Kapora,

Lake Malaŵi; 1935.

Diagnosis

Mylochromis semipalatus along with Mylochromis melanonotus in having a snout to dorsal fin origin length of greater than 35 % of the standard length, a preorbital head length of less than

40 % head length and 18 dorsal spines. M. semipalatus has M. melanonotus by a longer snout length (40 – 41 % versus 31 % HL) and a shorter preorbital head length (30 – 33 % versus 39 %

101

HL) than M. melanonotus. Meristically, M. semipalatus has more anal rays (9 versus 8), more teeth rows on upper jaw (4 – 5 versus 3) and more teeth rows on lower jaw (5 versus 3) than M. melanonotus.

Description

Morphometric and meristic data in Table 13. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 18 spines and 10 dorsal rays. Anal fin with 3 spines and 9 anal rays. Lateral lines scales 33 with 1 pored scale. Gill rakers on first ceratobranchial 11 - 12 and on first epibranchial 4.

Basic color mostly yellow. Frequently, yellow pigmentation especially distinct in head, chest and lower flank area. Fins also yellow color. Yellow color more distinct in younger specimens while not present in fully mature specimens. Dominant males blue to green in head area, but not on flanks (Spreinat 1995).

Field observations

Mylochromis semipalatus prefers sandy or mixed substrates. This species is solitary and sometimes is found in small groups (Spreinat 1995).

Distribution

Probably widely distributed in the entire lake, but nowhere frequently encountered (Spreinant

1995).

102

Table 13. Morphometric and meristic values of Mylochromis mollis (n = 1), Mylochromis

obtusus (n = 1) and Mylochromis semipalatus (n = 2)

M. mollis M. obtusus M. semipalatus

(n = 1) (n = 1) (n = 3)

range

Standard length, mm 85.7 – 132.3 188.5 140.5 – 148.1

Head length, mm 25.4 – 41.5 59.1 46.4 – 49.8

Percent standard length

Head length 30 – 31 31 33 – 34

Snout to dorsal-fin origin 35 – 38 35 37 – 39

Snout to pelvic-fin origin 38 – 41 42 40 – 42

Dorsal-fin base length 55 – 58 53 53 – 54

Anterior dorsal to anterior anal 51 52 51 – 52

Anterior dorsal to posterior anal 59 – 61 61 59

Posterior dorsal to anterior anal 28 – 29 32 29 – 30

Posterior dorsal to posterior anal 13 – 15 18 14 – 15

Posterior dorsal to ventral caudal 17 – 18 20 18 – 20

Posterior anal to dorsal caudal 19 - 20 21 19

Anterior dorsal to pelvic-fin origin 36 – 37 40 38

103

Posterior dorsal to pelvic-fin origin 53 – 54 56 53 – 56

Caudal-peduncle length 17 – 18 17 17

Least caudal-peduncle depth 11 – 12 11 12

Body depth 33 – 35 40 36 – 37

Percent head length

Snout length 36 – 38 34 40 – 41

Postorbital head length 37 – 40 40 34 – 35

Horizontal eye diameter 31 – 35 23 29 – 30

Vertical eye diameter 27 – 33 21 27

Preorbital length 32 – 35 45 30 – 33

Cheek depth 21 – 24 25 23 – 25

Lower-jaw length 31 – 33 39 39 – 41

Head depth 66 – 70 81 67 – 74

Counts

Dorsal-fin spines 16 – 17 17 18

Dorsal-fin rays 11 10 10

Anal-fin spines 3 3 3

Anal-fin rays 8 9 9

Pectoral-fin rays 13 - 14 13 14

104

Pelvic-fin rays 5 5 5

Lateral-line scales 31 – 33 32 33

Pored scales posterior of lateral line 0 – 1 0 1

Scale rows on cheek 3 3 4

Gill rakers on first ceratobranchial 13 – 15 12 11 – 12

Gill rakers on first epibranchial 3 – 4 3 4

Teeth in outer row of left lower jaw 11 – 15 14 16 – 17

Teeth rows on upper jaw 3 – 4 4 4 – 5

Teeth rows on lower jaw 3 – 5 5 5

105

19. Mylochromis sphaerodon (Regan 1922)

Figure 33. Mylochromis sphaerodon (Regan). Lectotype, 90 mm standard length. Source: Eccles and Trewavas (1989).

Material examined

BMNH1921.9.6.146-147; paralectotype; 2; 90.5 – 93.1 mm SL; Lake Malaŵi.

Diagnosis

Mylochromis sphaerodon along with Mylochromis balteatus, Mylochromis incola,

Mylochromis lateristriga, Mylochromis melanotaenia, Mylochromis mola and Mylochromis subocularis has a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than 40 % and dorsal spines less than 17.

106

Mylochromis sphaerodon has a smaller cheek depth (20 % versus 22 – 29 % HL), a longer posterior dorsal to posterior anal length (29 % versus 13 – 15 % SL), a shorter snout length (35 –

36 % versus 39 – 43 % HL), fewer lateral line scales (30 versus 31 – 32) and more teeth rows on lower jaw (5 versus 4) than M. balteatus. Mylochromis sphaerodon has a shorter snout length (35

– 36 % versus 39 – 46 % HL), a longer posterior dorsal to posterior anal length (15 % versus 12

– 14 % SL) and a longer dorsal fin base length (54 – 55 % versus 48 – 52 % SL) than M. incola.

There is a lot of overlap in both morphometric measurements and meristic counts between M. sphaerodon and M. lateristriga. M. sphaerodon has a longer snout to dorsal length than M. lateristriga (37 – 42 % versus 35 – 40 % SL). Mylochromis sphaerodon has a longer preorbital head length (31 – 32 % versus 26 – 27 % % HL), a smaller body depth (62 – 65 % versus 66 –

71 % HL) fewer cheek scales (2 – 3 versus 4) and more teeth on the left lower jaw (2 – 3 versus

4) than M. melanotaenia. Mylochromis sphaerodon has fewer teeth rows on the lower jaw (5 versus 6) than M. mola. Mylochromis sphaerodon has more dorsal rays (11 versus 8 – 10) and more pectoral rays (14 versus 10 – 13) than M. subocularis.

Description

Morphometric and meristic data in Table 14. Solid diagonal stripe along the side of the body.

107

Females and immature males with conspicuous black oblique stripe. Silvery on flanks, darker dorsally. Pelvic and anal fins bright yellow. Ripe males bluish, with orange spots on flank scales, caudal and dorsal fins, and white dorsal fin margin (Turner 1996).

Field observations

Mylochromis sphaerodon is encountered in shallow waters. It is a snail eater and uses the powerful teeth on the pharyngeal jaws to crush the snails and other invertebrates (Konings 2007).

Distribution

It is restricted to the southern part of the lake (Konings 2007).

Discussion

Although there was an overlap between the character states of M. sphaerodon and M. lateristriga, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 34).

108

Figure 34. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. sphaerodon and M. lateristriga.

20. Mylochromis spilostichus (Trewavas 1935)

Figure 35. Mylochromis spilostichus (Trewavas). Holotype, male, 181 mm standard length.

109

Source: Eccles and Trewavas (1989).

Material examined

BMNH1935.6.14.1459; holotype; 1; 179.9 mm SL; Lake Malaŵi, Monkey Bay.

Diagnosis

Mylochromis spilostichus along with Mylochromis chekopae, Mylochromis ensatus,

Mylochromis ericotaenia, Mylochromis formosus, Mylochromis gracilis, Mylochromis guentheri and Mylochromis labidodon have a snout to dorsal fin origin length of less than 35 % of the standard length. It can be distinguished from all of the rest by longer snout length of greater than

25 % head length.

Description

Morphometric and meristic data in Table 9. Solid diagonal stripe along the side of the body.

Females and immature males brownish, paler ventrally. Prominent dark oblique stripe with 7

– 8 spots and generally with dark vertical bars conspicuous dorsally, but inconspicuous or absent ventrally. Dark spot at posterior end of caudal peduncle. Dorsal and caudal fins with faint spots

Ripe males with golden flanks; scales with blue outline, brownish dorsally with gold and blue iridescence, white ventrally. Lips and upper part of head iridescent blue, chest and branchiostegal

110 membrane yellow. Dorsal and caudal fins with dark yellow spots. Anal fin dark yellow with broad dark bar, no egg spots. Dorsal fin margin white with orange tips and a dark submarginal band. Pelvics orange with a dark bar and white leading edge. Faint vertical bars and oblique stripe on upper part of flank (Turner 1996).

Field observations

Mylochromis spilostichus has been observed to hunt small fishes over the sand at a depth of about 35 meters. Territorial males defend small shallow spawning pits in the sand near rocks.

Mouthbrooding females move about over the sand.

21. Mylochromis subocularis (GÜnther 1864)

Figure 36. Mylochromis subocularis (GÜnther 1864). Source: Konings (2007).

111

Material examined

BMNH1893.11.15.24-32; 11; 36.7 – 57.1 mm SL; Lake Malaŵi and Upper Shire River.

Diagnosis

Mylochromis subocularis along with Mylochromis balteatus, Mylochromis incola,

Mylochromis lateristriga, Mylochromis melanotaenia, Mylochromis mola and Mylochromis sphaerodon have a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than 40 % and dorsal spines less than 17.

Mylochromis subocularis has fewer lateral line scales (26 – 30 versus 31 – 32) and fewer pectoral rays (10 – 13 versus 14) than M. balteatus. Mylochromis subocularis has fewer pectoral rays (10 – 13 versus 14 – 15) than M. incola. Mylochromis subocularis has a shorter caudal peduncle length (15 – 18 % versus 18 – 20 % SL) and fewer dorsal rays (8 – 10 versus 10 – 12) than M. lateristriga. Mylochromis subocularis has fewer anal rays (7 – 8 versus 9 – 10) than M. melanotaenia. Mylochromis subocularis has fewer teeth rows on upper jaw (2 – 4 versus 6) and fewer pectoral rays (10 – 13 versus 14) than M. mola. Mylochromis subocularis has fewer dorsal rays (8 – 10 versus 11) and fewer pectoral rays (10 – 13 versus 14) than M. sphaerodon.

Description

Morphometric and meristic data in Table 14. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 14 - 16 spines (mode 15) and 8 - 10 dorsal rays (mode 9). Anal fin with 3 spines and 7 - 8 anal rays (mode 7). Lateral lines scales 26 – 30 (mode 27, 28) with no

112 pored scale. Gill rakers on first ceratobranchial 8 - 9 (mode 9) and on first epibranchial 3 – 4

(mode 3).

Color description not available for live specimens.

Field observations

Mylochromis subocularis males form small breeding colonies in the shallow spawning pits.

Territorial males can be found as close as a meter apart.

Distribution

Mylochromis subocularis is common at most locations around the lake (Konings 2007).

Discussion

Although there was an overlap between the character states of M. subocularis and M. lateristriga, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 37).

113

Figure 37. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. subocularis and M. lateristriga.

114

Table 14. Morphometric and meristic values of Mylochromis sphaerodon (n = 2), Mylochromis

spilostichus (n = 1) and Mylochromis subocularis (n = 2)

M. sphaerodon M. spilostichus M. subocularis

(n = 2) (n = 1) (n = 3)

Range Range

Standard length, mm 90.5 – 93.1 179.9 36.7 - 57.1

Head length, mm 30.6 – 31.4 54.1 13.1 – 20.3

Percent standard length

Head length 33 – 35 30 34 – 36

Snout to dorsal-fin origin 37 – 42 30 35 – 40

Snout to pelvic-fin origin 38 – 41 37 38 – 42

Dorsal-fin base length 54 – 55 56 52 – 55

Anterior dorsal to anterior anal 48 – 49 46 44 – 49

Anterior dorsal to posterior anal 58 – 59 59 55 – 60

Posterior dorsal to anterior anal 29 27 26 – 31

Posterior dorsal to posterior anal 15 13 12 – 15

Posterior dorsal to ventral caudal 18 18 16 – 19

Posterior anal to dorsal caudal 20 20 15 – 19

Anterior dorsal to pelvic-fin origin 34 – 36 29 32 – 37

115

Posterior dorsal to pelvic-fin origin 50 – 51 51 49 – 55

Caudal-peduncle length 18 19 15 – 18

Least caudal-peduncle depth 11 10 11 – 13

Body depth 33 – 34 27 33 – 35

Percent head length

Snout length 35 – 36 23 28 – 34

Postorbital head length 38 – 39 43 38 – 44

Horizontal eye diameter 33 – 34 29 31 – 37

Vertical eye diameter 32 – 34 26 29 – 37

Preorbital length 31 – 32 34 18 – 24

Cheek depth 20 21 16 – 23

Lower-jaw length 30 – 33 43 31 – 41

Head depth 62 – 65 63 57 – 70

Counts

Dorsal-fin spines 15 – 16 18 14 – 16

Dorsal-fin rays 11 12 8 – 10

Anal-fin spines 3 3 8 – 10

Anal-fin rays 8 9 7 – 8

Pectoral-fin rays 14 13 10 - 13

116

Pelvic-fin rays 5 5 5

Lateral-line scales 30 36 26 – 30

Pored scales posterior of lateral 0 1 0 line

Scale rows on cheek 2 – 3 3 3 – 4

Gill rakers on first ceratobranchial 9 12 8 – 9

Gill rakers on first epibranchial 3 – 4 3 3 – 4

Teeth in outer row of left lower 18 – 19 19 11 – 17 jaw

Teeth rows on upper jaw 4 – 6 2 2 – 4

Teeth rows on lower jaw 5 3 2 – 5

117

B. New Species

1. Mylochromis boadzului, new species

Figure 38. Holotype of Mylochromis boadzului.

Etymology

From the Greek, „boadzului‟ means from Boadzulu, which indicates it is found around

Boadzulu Island.

Material examined

Holotype. PSU 6008; 1; 98.8 mm SL; Lake Malaŵi, Boadzulu Island, 14º15.291S

35º08.490E; Stauffer, 9 February 2004.

Paratypes. PSU 6008; 8; 79.9 – 101.1 mm SL; data as for holotype.

Diagnosis

Mylochromis boadzului along with Mylochromis balteatus, Mylochromis incola,

Mylochromis lateristriga, Mylochromis melanotaenia, Mylochromis mola, Mylochromis

118 sphaerodon, Mylochromis subocularis, Mylochromis boadzului (new species), Mylochromis lapararhabdos (new species), Mylochromis lithoschalis (new species), Mylochromis lupingui

(new species), Mylochromis mesembrinos (new species), Mylochromis notos (new species),

Mylochromis rhabdos (new species) and Mylochromis strombodaptes (new species) have a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than 45 % HL.

Mylochromis boadzului has a shorter lower jaw length (26 – 31 % versus 31 – 40 % HL), a deeper least caudal peduncle depth (12 – 13 % versus 10 – 12 % SL), more dorsal spines (16 –

18 versus 15 – 16) and fewer dorsal rays (8 – 10 versus 10 – 11) than M. balteatus. Mylochromis boadzului has a longer post dorsal to post anal length (15 – 17 versus 12 – 14 % SL) than M. incola. Mylochromis boadzului has a longer post dorsal to anterior anal length (31 – 33 % versus

25 – 29 % SL) than M. lateristriga. Mylochromis boadzului has a longer post dorsal to pelvic-fin origin length (55 – 59 % versus 49 – 52 % SL) and fewer cheek scales (2 – 3 versus 4) than M. melanotaenia. Mylochromis boadzului has fewer teeth rows on upper jaw (2 – 5 versus 6) and fewer teeth rows on lower jaw (2 – 5 versus 6) than M. mola. Mylochromis boadzului has a longer post dorsal to pelvic-fin origin length (55 – 59 % versus 50 – 51 % SL) and fewer dorsal rays (8 – 10 versus 11) than M. sphaerodon. Mylochromis boadzului has a longer preorbital head length (26 – 40 % versus 18 – 24 % HL) and more lateral scales (31 – 33 versus 26 – 30) than M. subocularis. Mylochromis boadzului has fewer dorsal rays (8 – 10 versus 11) and fewer anal rays

(7 – 8 versus 9 – 10) than M. notos. Mylochromis boadzului has fewer anal rays (7 – 8 versus 8 –

9) than M. mesembrinos. Mylochromis boadzului has a longer least caudal peduncle length (12 –

13 % versus 10 – 12 % SL), fewer dorsal rays (8 – 10 versus 10 – 11) and fewer lateral line scales (28 – 32 versus 31 – 33) than M. strombodaptes. Mylochromis boadzului has a longer preorbital length (26 – 40 % versus 22 – 25 % HL) than M. lithoschalis. Mylochromis boadzului

119 has a shorter lower jaw length (26 – 31 % versus 32 – 38 % HL), shorter snout length (32 – 40 % versus 42 – 44 % HL) and fewer gill rakers on the first ceratobranchial (8 – 9 versus 12 – 14) than M. lupingui. Mylochromis boadzului has a shorter lower jaw length (26 – 31 % versus 31 –

38 % HL) and fewer gill rakers on the first ceratobranchial (8 – 9 versus 9 – 11) than M. rhabdos. Mylochromis boadzului has a shorter lower jaw length (26 – 31 % versus 33 – 34 %

HL), a shorter snout length (32 – 40 versus 43 – 45 % HL), more lateral line scales (31 – 33 versus 30) and fewer gill rakers on the first ceratobranchial (8 – 9 versus 11) than M. lapararhabdos.

Description

Morphometric and meristic data in Table 15. Blotched diagonal stripe along the side of the body. Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 16 – 18 spines (mode 17) and 8 – 10 (mode 10) dorsal rays.

Anal fin with 3 spines and 7 - 8 anal rays (mode 8). Lateral lines scales 31 - 33 (mode 31) with 0

- 1 pored scales (mode 0). Gill rakers on first ceratobranchial 8 – 9 (mode 8) and on first epibranchial 3 – 4 (mode 3).

Head gray with yellow, blue green highlights. Lower jaw with fluorescent green outline; white gular. Interorbital gray to green. Dorsal third of lateral side with gray ground color to yellow white ventrally. Scales yellow outline. Diagonal stripe broken and black. Dorsal fin gray with yellow brown spots. Marginal band gray with white lappets and yellow tips. Caudal fin yellow gray with white spots. Anal fin clear with yellow spots. First and second rays of pelvic fin with pale yellow membranes; remainder clear. Pectoral rays clear.

Field observations: Not recorded

120

Discussion

Although there was an overlap between the character states of M. boadzului and M. balteatus, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 39).

M. boadzului M. balteatus

0.10

)

a t

a 0.05

r t

e 0.00

p r

o -0.05

(

2 C

P -0.10

R H

S -0.15

-0.20 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 PCA1 (meristic data)

Figure 39. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. boadzului and M. balteatus.

Although there was an overlap between the character states of M. boadzului and M. mesembrinos, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were

121 heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 40).

0.10 M. boadzului M. mesembrinos

) 0.05

c i

r 0.00

o h

p -0.05

(

C -0.10

R H

S -0.15

-0.20 -2 -1 0 1 2 PCA1 (meristic data)

Figure 40. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. boadzului and M. mesembrinos.

Although there was an overlap between the character states of M. boadzului and M. strombodaptes, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 41).

122

0.10 M. boadzului

M. strombodaptes

) a

t 0.05

r t

e 0.00

r o

m -0.05

(

_ D

R -0.10

H S

-0.15 -2 -1 0 1 2 PCA1 (meristic data)

Figure 41. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. boadzului and M. strombodaptes.

Although there was an overlap between the character states of M. boadzului and M. lithoschalis, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 42).

123

M. boadzului

0.10 M. lithoschalis

)

a t

a 0.05

t e

m 0.00

o m

( -0.05

_ D

R -0.10

H S

-0.15

-2 -1 0 1 2 PCA 1 (meristic data)

Figure 42. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. boadzului and M. lithoschalis.

124

Table 15. Morphometric and meristic values of Mylochromis boadzului (n = 9)

Holotype Mean Range

Standard length, mm 98.8 92.3 79.9 – 101.1

Head length, mm 33.2 31.2 26.7 – 36.4

Percent standard length

Head length 34 33.8 32 – 36

Snout to dorsal-fin origin 39 38.9 37 – 41

Snout to pelvic-fin origin 39 38.7 36 – 41

Dorsal-fin base length 61 57.4 55 – 61

Anterior dorsal to anterior anal 54 51.1 48 – 54

Anterior dorsal to posterior anal 65 61.3 59 – 65

Posterior dorsal to anterior anal 32 32.1 31 – 33

Posterior dorsal to posterior anal 15 15.7 15 – 17

Posterior dorsal to ventral caudal 18 18.4 16 – 21

Posterior anal to dorsal caudal 19 19.8 18 – 21

Anterior dorsal to pelvic-fin origin 38 39.0 37 – 41

Posterior dorsal to pelvic-fin origin 56 56.4 55 – 59

125

Caudal-peduncle length 18 17.8 16 – 20

Least caudal-peduncle depth 13 12.4 12 - 13

Body depth 37 35.9 31 - 38

Percent head length

Snout length 36 35.8 32 - 40

Postorbital head length 41 32.0 25 - 41

Horizontal eye diameter 32 32.1 28 - 36

Vertical eye diameter 34 33.1 30 - 34

Preorbital length 29 30.1 26 - 40

Cheek depth 23 21.6 19 - 24

Lower-jaw length 27 28.0 26 - 31

Head depth 65 66.7 60 - 74

Counts Mode Range

Dorsal-fin spines 17 17 16 - 18

Dorsal-fin rays 10 10 8 – 10

Anal-fin spines 3 3 3

Anal-fin rays 8 8 7 – 8

126

Pectoral-fin rays 14 5 13 – 14

Pelvic-fin rays 5 13 5

Lateral-line scales 32 31 31 – 33

Pored scales posterior of lateral line 0 0 0 – 1

Scale rows on cheek 2 3 2 – 3

Gill rakers on first ceratobranchial 9 8 8 – 9

Gill rakers on first epibranchial 3 3 3 – 4

Teeth in outer row of left lower jaw 6 12 7 – 13

Teeth rows on upper jaw 3 4 2 – 5

Teeth rows on lower jaw 5 4 2 - 5

127

2. Mylochromis lapararhabdos, new species

Figure 43. Holotype of Mylochromis lapararhabdos.

Etymology

From the Greek, „lapararhabdos‟ means flank stripe, which indicates the diagonal stripe on the body side.

Material examined

Holotype. PSU 6016; 1; 101.8 mm SL, Otter Point, Lake Malaŵi, 14 02.756S 34

49.498E; Stauffer, 7th February 2005

Paratype. PSU 6017; 1; 89.7 mm SL; data as for holotype.

Diagnosis

Mylochromis lapararhabdos along with Mylochromis balteatus, Mylochromis incola,

Mylochromis lateristriga, Mylochromis melanotaenia, Mylochromis mola, Mylochromis

128 sphaerodon, Mylochromis subocularis, Mylochromis boadzului (new species), Mylochromis lapararhabdos (new species), Mylochromis lithoschalis (new species), Mylochromis lupingui

(new species), Mylochromis mesembrinos (new species), Mylochromis notos (new species),

Mylochromis rhabdos (new species) and Mylochromis strombodaptes (new species) have a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than 45 % HL.

Mylochromis lapararhabdos has a shallower cheek depth (15 – 17 % versus 22 – 29 % HL), more pored scales posterior of lateral line (2 versus 0 – 1) and more gill rakers on the first ceratobranchial (11 versus 8 – 10) than M. balteatus. Mylochromis lapararhabdos has a smaller horizontal eye diameter (22 – 27 % versus 28 – 33 % HL) and more gill rakers on the first ceratobranchial (11 versus 8 – 10) than M. incola. Mylochromis lapararhabdos has a longer snout length (43 – 48 % versus 31 – 41 % HL) than M. lateristriga. Mylochromis lapararhabdos has a longer snout length (43 – 48 % versus 37 – 39 % HL), a longer preorbital length (30 – 33

% versus 26 – 27 % HL), a shorter vertical eye diameter (22 – 26 % versus 28 – 36 % HL), fewer lateral line scales (30 versus 31 – 32) and more gill rakers on the first ceratobranchial (11 versus

9) than M. melanotaenia. Mylochromis lapararhabdos has fewer teeth rows on the lower jaw (3 -

4 versus 6), fewer teeth rows on the upper jaw (4 versus 6) and more pored scales posterior of lateral line (2 versus 0) than M. mola. Mylochromis lapararhabdos has a shorter post dorsal to post anal length (12 – 13 % versus 15 % SL), a shorter caudal peduncle length (16 – 17 % versus

18 % SL), a shorter post anal to dorsal caudal length (17 – 19 % versus 20 % SL), fewer cheek scales (3 – 4 versus 5) and more pored scales posterior of lateral line (2 versus 0) than M. sphaerodon. Mylochromis lapararhabdos has a longer preorbital length (30 – 33 % versus 18 –

24 % HL), more pored scales posterior of the lateral line (2 versus 0), more dorsal rays (11 versus 8 – 10) and more pectoral rays (14 – 15 versus 10 – 13) than M. subocularis. M.

129 lapararhabdos has a longer head length (37 – 40 % versus 32 – 34 % SL), more gill rakers on the first ceratobranchial (11 versus 8 – 9), fewer lateral line scales (30 versus 33 – 35) and more teeth rows on the upper jaw (4 versus 2 – 3) than M. notos. Mylochromis lapararhabdos has more pectoral rays than M. mesembrinos (14 – 15 versus 13 – 14). Mylochromis lapararhabdos has a longer snout length (43 – 45 % versus 30 – 39% HL) than M. strombodaptes. Mylochromis lapararhabdos has a longer lower jaw length (33 – 34 % versus 26 – 31 % HL), a longer snout length (43 – 45 % versus 32 – 40 % HL), fewer lateral line scales (30 versus 31 – 33) and more gill rakers on the first ceratobranchial (11 versus 8 – 9) than M. boadzului. Mylochromis lapararhabdos has a longer preorbital length (30 – 33 % versus 22 – 25 % HL), a longer snout length (43 – 45 % versus 25 – 33 % HL), a shorter cheek depth (15 – 17 % versus 20 – 25 %

HL), more gill rakers on the first ceratobranchial (11 versus 8 – 9) and fewer lateral line scales

(30 versus 31 – 34) than M. lithoschalis. Mylochromis lapararhabdos has a longer preorbital length (30 – 32 % versus 21 – 26 % HL), a smaller horizontal eye diameter (22 – 27 % versus 33

– 41 % HL), a longer snout length (43 – 45 % versus 26 – 39 HL) and more dorsal fin rays (11 versus 9 – 10) than M. rhabdos. Mylochromis lapararhabdos has a bigger horizontal eye diameter (22 – 27 % versus 29 – 32 % HL) than M. lupingui.

Description

Morphometric and meristic data in Table 16. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 15 - 17 spines and 11 dorsal rays. Anal fin with 3 spines and 8 anal rays. Lateral lines scales 30 with 2 pored scales. Gill rakers on first ceratobranchial 11 and on first epibranchial 4.

130

Discussion

Although there was an overlap between the character states of M. lapararhabdos and M. mesembrinos, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 44).

0.1 M. lapararhabdos

M. mesembrinos

)

a t

a 0.0

e m

o -0.1

(

C -0.2

H S -0.3

-1 0 1 2 3 PCA1 (meristic data)

Figure 44. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lapararhabdos and M. mesembrinos.

131

Table 16. Morphometric and meristic values of Mylochromis lapararhabdos (n = 2)

Holotype Mean Range

Standard length, mm 101.8 95.8 89.7 – 101.8

Head length, mm 41.0 37.0 33.0 – 41.0

Percent standard length

Head length 40 38.5 37 - 40

Snout to dorsal-fin origin 43 41.5 40 – 43

Snout to pelvic-fin origin 46 44.0 42 – 46

Dorsal-fin base length 51 51.5 51 - 52

Anterior dorsal to anterior anal 45 45.0 45

Anterior dorsal to posterior anal 53 54.0 53 – 55

Posterior dorsal to anterior anal 26 27.0 26 – 28

Posterior dorsal to posterior anal 13 12.5 12 – 13

Posterior dorsal to ventral caudal 16 17.0 16 – 18

Posterior anal to dorsal caudal 19 18.0 17 – 19

Anterior dorsal to pelvic-fin origin 33 33.5 33 - 34

Posterior dorsal to pelvic-fin origin 48 49.0 48 – 50

132

Caudal-peduncle length 17 16.5 16 – 17

Least caudal-peduncle depth 11 11.0 11

Body depth 31 31.5 31 - 32

Percent head length

Snout length 45 44.0 43 – 45

Postorbital head length 35 36.0 35 – 37

Horizontal eye diameter 22 24.5 22 – 27

Vertical eye diameter 22 24.0 22 – 26

Preorbital length 30 31.5 30 – 33

Cheek depth 15 16.0 15 – 17

Lower-jaw length 34 33.5 33 – 34

Head depth 53 54.0 53 - 55

Counts Mode Range

Dorsal-fin spines 17 NA 15 – 17

Dorsal-fin rays 11 11 11

Anal-fin spines 3 3 3

Anal-fin rays 8 8 8

133

Pectoral-fin rays 14 NA 14 - 15

Pelvic-fin rays 5 5 5

Lateral-line scales 30 30 30

Pored scales posterior of lateral line 2 2 2

Scale rows on cheek 3 NA 3 – 4

Gill rakers on first ceratobranchial 11 11 11

Gill rakers on first epibranchial 4 4 4

Teeth in outer row of left lower jaw 12 NA 6 – 12

Teeth rows on upper jaw 4 4 4

Teeth rows on lower jaw 4 NA 3 - 4

134

3. Mylochromis lithoschalis, new species

Figure 45. Holotype of Mylochromis lithoschalis.

Etymology

From the Greek, „lithoschalis‟ means stone roller, which indicates it rolls stones in search for invertebrates.

Material examined

Holotype. PSU 6010; 1; 106.6 mm SL; Lake Malaŵi, Mumbo Island; Stauffer, 12

February 2004.

Paratypes. PSU 6011; 11; 85.3 – 106.6 mm SL; data as for holotype.

135

Diagnosis

Mylochromis lithoschalis along with Mylochromis balteatus, Mylochromis incola,

Mylochromis lateristriga, Mylochromis melanotaenia, Mylochromis mola, Mylochromis sphaerodon, Mylochromis subocularis, Mylochromis boadzului (new species), Mylochromis lapararhabdos (new species), Mylochromis lithoschalis (new species), Mylochromis lupingui

(new species), Mylochromis mesembrinos (new species), Mylochromis notos (new species),

Mylochromis rhabdos (new species) and Mylochromis strombodaptes (new species) have a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than 45 % HL.

Mylochromis lithoschalis has a shorter snout length (25 – 33 % versus 39 – 43 % HL) and a shorter preorbital head length (22 – 25 % versus 29 – 35 % HL) than M. balteatus. Mylochromis lithoschalis has shorter snout length (25 – 33 % versus 39 – 46 % HL), a shorter preorbital length

(22 – 25 % versus 30 – 33 % HL) and a longer post dorsal to post anal length (14 – 16 % versus

12 – 14 % SL) than M. incola. Mylochromis lithoschalis has a shorter postorbital head length (26

– 31 % versus 34 – 41 % HL) than M. lateristriga. Mylochromis lithoschalis has a shorter snout length (25 – 33 % versus 37 – 39 % HL) and fewer cheek scales (2 – 3 versus 4) than M. melanotaenia. Mylochromis lithoschalis has a shorter snout length (25 – 33 % versus 38 – 44 %

HL), a shorter preorbital length (22 – 25 % versus 31 – 34 % HL), a shorter post orbital head length (26 – 31 % versus 34 – 38 % HL), fewer teeth rows in the upper jaw (2 – 5 versus 6) and fewer teeth rows in the lower jaw (2 – 5 versus 6) than M. mola. Mylochromis lithoschalis has a shorter snout length (25 – 33 % versus 35 – 36 % HL), a shorter preorbital length (22 – 25 % versus 31 – 32 % HL), a shorter post orbital head length (26 – 31 % versus 38 – 39 % HL) and

136 more lateral line scales (31 – 34 versus 30) than M. sphaerodon. Mylochromis lithoschalis has a shorter post orbital head length (26 – 31 % versus 38 – 44 % HL) and more lateral line scales (31

– 34 versus 26 – 30) than M. subocularis. M. lithoschalis has shorter snout length (25 – 33 % versus 40 – 46 % HL) and a shorter preorbital length (22 – 25 % versus 29 – 35 % HL) than M. notos. Mylochromis lithoschalis has a shorter post orbital head length (26 – 31 % versus 39 – 42

% HL) and a shorter preorbital length (22 – 25 % versus 26 – 37 % % HL) than M. mesembrinos.

Mylochromis lithoschalis has a shorter postorbital head length than (26 – 31 % versus 34 – 42 %

HL) than M. strombodaptes. Mylochromis lithoschalis has a shorter preorbital length (22 – 25 % versus 26 – 40 % SL) than M. boadzului. Mylochromis lithoschalis has a shorter snout length (25

– 33 % versus 42 – 44 % HL), a shorter preorbital length (22 – 25 % versus 31 – 34 % HL) and fewer gill rakers on the first ceratobranchial (8 – 9 versus 12 – 14) than M. lupingui.

Mylochromis lithoschalis has a shorter lower jaw length (23 – 32 % versus 31 – 38 % HL), a shorter post orbital head length (26 – 31 % versus 30 – 35 % HL) and fewer gill rakers on the first epibranchial (8 – 9 versus 9 – 11) than M. rhabdos. Mylochromis lithoschalis has a shorter preorbital length (22 – 25 % versus 30 – 33 % HL), a shorter snout length (25 – 33 % versus 43 –

45 % HL), a longer cheek depth (20 – 25 % versus 15 – 17 % HL), fewer gill rakers on the first ceratobranchial (8 – 9 versus 11) and more lateral line scales (31 – 34 versus 30) than M. lapararhabdos.

Description

Morphometric and meristic data in Table 17. Blotched diagonal stripe along the side of the body. Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 16 – 17 spines (mode 17) and 9 - 11 dorsal rays (mode 11).

Anal fin with 3 spines and 7 – 9 anal rays (mode 8). Lateral lines scales 31 – 34 (mode 32) with

137

0 - 1 pored scales (mode 0). Gill rakers on first ceratobranchial 8 – 9 (mode 9) and on first epibranchial 3 – 4 (mode 3).

Head pale yellow with gray marks and interorbital gray to brown. Operculum black.

Gular region pale yellow. Lower jaw with blue green outline. Lateral side with silver ground color. Scales with yellow outline. Diagonal stripe uninterrupted. Breast pale yellow while belly white. Dorsal fin gray with yellow tinged orange tips. Caudal rays clear with membranes with yellow vermiculations. Anal fin clear with yellow marks. Pelvic fin pale yellow to clear while pectoral rays with pale yellow membranes.

Field observations

Some individuals at Mumbo Island have been observed to roll over small pebbles in the same fashion as M. labidodon. Most individuals behave as opportunistic scavengers that are also attracted to stirred-up material. Breeding individuals have been encountered only at Boadzulu

Island, where they defend small sand-scrape bowers at a depth of about 20 to 25 meters.

Mouthbrooding females have been seen at the same depths and were solitary (Konings, 2007).

Distribution

Mylochromis lithoschalis is found in the southern part of Lake Malaŵi. It occurs in the intermediate habitats. It was first recognized at Mumbo Island and later at most other locations south of Senga Point, where it is quite found in pure rocky habitats such as Chinyankhwazi

Island and Zimbabwe Rock (Konings, 2007).

138

Discussion

Although there was an overlap between the character states of M. lithoschalis and M. rhabdos, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 46).

0.2 M. lithoschalis

M. rhabdos

)

a d

0.1

h p

r 0.0

(

P _

D -0.1

H S

-0.2 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 PCA1 (meristic data)

Figure 46. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lithoschalis and M. rhabdos.

139

Table 17. Morphometric and meristic values of Mylochromis lithoschalis (n = 12)

Holotype Mean Range

Standard length, mm 106.6 93.7 85.3 – 106.6

Head length, mm 35.6 31.9 28.7 – 36.6

Percent standard length

Head length 33 34.2 33 – 36

Snout to dorsal-fin origin 39 39.1 37 – 41

Snout to pelvic-fin origin 40 39.5 34 – 44

Dorsal-fin base length 58 55.8 53 – 58

Anterior dorsal to anterior anal 50 49.3 48 51

Anterior dorsal to posterior anal 62 59.8 57 – 62

Posterior dorsal to anterior anal 32 31.0 30 – 32

Posterior dorsal to posterior anal 16 14.9 14 – 16

Posterior dorsal to ventral caudal 19 18.0 17 – 19

Posterior anal to dorsal caudal 19 19.5 16 – 21

Anterior dorsal to pelvic-fin origin 40 38.2 37 – 40

Posterior dorsal to pelvic-fin origin 53 54.5 53 – 56

140

Caudal-peduncle length 16 16.2 15 – 18

Least caudal-peduncle depth 12 11.8 11 – 13

Body depth 38 36.6 34 – 39

Percent head length

Snout length 28 28.7 25 – 33

Postorbital head length 39 28.6 26 – 31

Horizontal eye diameter 31 32.5 30 – 35

Vertical eye diameter 32 32.1 30 – 34

Preorbital length 22 23.4 22 – 25

Cheek depth 23 21.8 20 – 25

Lower-jaw length 29 28.7 23 – 32

Head depth 63 67.3 61 – 75

Counts Mode Range

Dorsal-fin spines 17 17 16 – 17

Dorsal-fin rays 10 11 9 – 11

Anal-fin spines 3 3 3

Anal-fin rays 7 8 7 – 9

141

Pectoral-fin rays 13 13 13 – 14

Pelvic-fin rays 5 5 5

Lateral-line scales 33 32 31 – 34

Pored scales posterior of lateral line 1 0 0 – 1

Scale rows on cheek 3 3 2 – 3

Gill rakers on first ceratobranchial 9 9 8 – 9

Gill rakers on first epibranchial 3 3 3 – 4

Teeth in outer row of left lower jaw 9 8 7 – 15

Teeth rows on upper jaw 3 3 2 – 5

Teeth rows on lower jaw 3 4 2 – 5

142

4. Mylochromis lupingui, new species

Figure 47. Holotype of Mylochromis lupingui.

Etymology

From the Greek, „lupingui‟ means from Lupinga, which indicates it is from Lupinga

Island.

Material examined

Holotype. PSU 6012; 1; 93.2 mm SL; Lupingu, Lake Malaŵi, Tanzania, 10 04.451S

34 32.378E; Stauffer, 8th February 2005.

Paratypes. PSU 6013; 3; 73.3 – 93.2 mm SL; data as for holotype.

143

Diagnosis

Mylochromis lupingui along with Mylochromis balteatus, Mylochromis incola, Mylochromis lateristriga, Mylochromis melanotaenia, Mylochromis mola, Mylochromis sphaerodon,

Mylochromis subocularis, Mylochromis boadzului (new species), Mylochromis lapararhabdos

(new species), Mylochromis lithoschalis (new species), Mylochromis lupingui (new species),

Mylochromis mesembrinos (new species), Mylochromis notos (new species), Mylochromis rhabdos (new species) and Mylochromis strombodaptes (new species) have a snout to dorsal fin origin length greater than 35 % SL and a preorbital head length of less than 45 % HL.

Mylochromis lupingui has a shallower cheek depth (13 – 18 % versus 22 – 29 % HL), more dorsal spines (17 versus 15 – 16) and more gill rakers on the first ceratobranchial (12 – 14 versus

8 – 10) than M. balteatus. Mylochromis lupingui has more dorsal spines (17 versus 15 – 16) and more gill rakers on the first ceratobranchial (12 – 14 versus 8 – 10) than M. incola. Mylochromis lupingui has a longer snout length (42 – 44 % versus 31 – 41 % HL) and more dorsal spines (17 versus 15 – 16) than M. lateristriga. Mylochromis lupingui has a longer preorbital length (31 –

34 % versus 26 – 27 % HL), a shallower cheek depth (13 – 18 % versus 23 – 27 % HL), more dorsal spines (17 versus 15 – 16), fewer cheek scales (2 – 3 versus 4) and more gill rakers on the first ceratobranchial (12 – 14 versus 9) than M. melanotaenia. Mylochromis lupingui has a shallower cheek depth (13 – 18 % versus 21 – 23 % HL), more gill rakers on the first ceratobranchial (12 – 14 versus 9 - 10) and more dorsal spines (17 versus 16) than M. mola.

Mylochromis lupingui has a longer snout length (42 – 44 % versus 35 – 36 % HL), a shallower cheek depth (13 – 18 % versus 20 % HL), more dorsal spines (17 versus 15 – 16) and more gill

144 rakers on the first ceratobranchial (12 – 14 versus 9) than M. sphaerodon. Mylochromis lupingui has longer preorbital length (31 – 34 % versus 18 – 24 % HL), a longer snout length (42 – 44 % versus 28 – 34 % HL), more gill rakers on the first ceratobranchial (12 – 14 versus 8 - 9), and more dorsal spines (17 versus 14 – 16) than M. subocularis. M. lupingui has a shallower cheek depth (13 – 18 % versus 20 – 24 % HL), more gill rakers on the first ceratobranchial (12 – 14 versus 8 – 9), fewer lateral line scales (30 – 31 versus 33 – 35) and fewer anal rays (8 versus 9 –

10) than M. notos. Mylochromis lupingui has more gill rakers on the first ceratobranchial (12 –

14 versus 8 – 12) and more teeth rows on the upper jaw (4 – 6 versus 2 – 4) than M. mesembrinos. Mylochromis lupingui has a longer snout length (42 – 44 % versus 30 – 39 % HL) and more gill rakers on the first ceratobranchial (12 – 14 versus 9 – 11) than M. strombodaptes.

Mylochromis lupingui has a longer lower jaw length (32 – 38 % versus 26 – 31 % HL), a longer snout length (42 – 44 % versus 32 – 40 % HL) and more gill rakers on the first ceratobranchial

(12 – 14 versus 8 – 9) than M. boadzului. Mylochromis lupingui has a longer snout length (42 –

44 % versus 25 – 33 % HL), a longer preorbital length (31 – 34 % versus 22 – 25 % HL) and more gill rakers on the first ceratobranchial (12 – 14 versus 8 – 9) than M. lithoschalis.

Mylochromis lupingui has a longer preorbital length (31 – 34 % versus 21 – 26 % HL), a longer snout length (42 – 44 % versus 26 – 39 % HL) and more gill rakers on the first ceratobranchial

(12 – 14 versus 9 – 11) than M. rhabdos. Mylochromis lupingui has a bigger horizontal eye diameter (29 – 32 % versus 22 – 27 % HL) than M. lapararhabdos.

Description

Morphometric and meristic data in Table 18. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 17 spines and 10 - 11 dorsal rays. Anal fin with 3 spines and 8

145 anal rays. Lateral lines scales 30 - 31 (mode 30) with 1 – 2 pored scales (mode 1). Gill rakers on first ceratobranchial 12 – 14 (mode 14) and on first epibranchial 4 – 5 (mode 4).

Head brown with black marks, black opecular spot, yellow gular. Dark brown ground color dorsally to light brown ventrally; breast pale yellow; breast pale yellow, belly white. Seven brown bas. Anterior portion of scale outlined in gold. Caudal peduncle brown. Dorsal fin gay with orange/brown spots; caudal fin brown; anal fin brown; pectoral fin clear with brown tinge; pelvic fin brown with clear membranes.

Discussion

Although there was an overlap between the character states of M. lupingui and M. mesembrinos, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 48).

146

M. lupungui

0.3 M. mesembrinos

)

a d

0.2

o h

p 0.1

(

C P

_ 0.0

H S

-0.1

-1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 PCA1 (meristic data)

Figure 48. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. lupingui and M. mesembrinos.

147

Table 18. Morphometric and meristic values of Mylochromis lupingui (n = 4)

Holotype Mean Range

Standard length, mm 93.2 81.8 73.3 – 93.2

Head length, mm 36.2 31.5 27.2 – 36.2

Percent standard length

Head length 39 38.3 37 - 39

Snout to dorsal-fin origin 43 42.3 42 – 43

Snout to pelvic-fin origin 44 44.5 44 - 45

Dorsal-fin base length 50 51.3 50 – 53

Anterior dorsal to anterior anal 45 44.5 44 – 45

Anterior dorsal to posterior anal 54 54.5 54 - 56

Posterior dorsal to anterior anal 27 27.3 27 – 28

Posterior dorsal to posterior anal 13 13.8 13 – 14

Posterior dorsal to ventral caudal 18 15.8 15 – 18

Posterior anal to dorsal caudal 17 17.0 15 – 18

Anterior dorsal to pelvic-fin origin 33 32.8 32 - 33

Posterior dorsal to pelvic-fin origin 47 48.3 47 – 50

148

Caudal-peduncle length 16 15.5 15 – 16

Least caudal-peduncle depth 11 10.8 10 - 11

Body depth 30 31.3 30 - 33

Percent head length

Snout length 43 43.0 42 - 44

Postorbital head length 33 33.8 31 – 38

Horizontal eye diameter 30 30.3 29 – 32

Vertical eye diameter 27 28.5 26 – 32

Preorbital length 34 33.3 31 – 34

Cheek depth 14 15.0 13 – 18

Lower-jaw length 38 35.0 32 – 38

Head depth 54 56.5 54 - 60

Counts Mode Range

Dorsal-fin spines 17 17 17

Dorsal-fin rays 10 10 10 – 11

Anal-fin spines 3 3 3

Anal-fin rays 8 8 8

149

Pectoral-fin rays 14 14 14

Pelvic-fin rays 5 5 5

Lateral-line scales 31 30 30 – 31

Pored scales posterior of lateral line 1 1 1 – 2

Scale rows on cheek 2 2 2 – 3

Gill rakers on first ceratobranchial 14 14 12 – 14

Gill rakers on first epibranchial 5 4 4 – 5

Teeth in outer row of left lower jaw 13 13 13 – 18

Teeth rows on upper jaw 5 5 4 – 6

Teeth rows on lower jaw 4 4 3 - 7

150

5. Mylochromis mesembrinos, new species

Figure 49. Holotype of Mylochromis mesembrinos.

Etymology

From the Greek, „mesembrinos‟ means southern, which indicates it‟s from southern Lake

Malaŵi.

Material examined

Holotype. PSU 6004; 1; 140.5 mm SL; South-East arm of Malaŵi; Stauffer, 17th December

1995.

Paratypes. PSU 6005; 16; 68.3 – 142.4 mm SL; data as for holotype.

151

Diagnosis

Mylochromis mesembrinos along with Mylochromis balteatus, Mylochromis incola,

(new species), Mylochromis mesembrinos (new species), Mylochromis notos (new species),

Mylochromis rhabdos (new species) and Mylochromis strombodaptes (new species) have a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than 45 % HL.

Mylochromis mesembrinos has a shorter lower jaw length (24 – 34 % versus 31 – 40 % HL), more dorsal spines (16 – 18 versus 15 – 16) and fewer teeth rows on lower jaw (2 – 4 versus 3 –

5) than M. balteatus. Mylochromis mesembrinos has more dorsal spines (16 – 18 versus 15 – 16) and fewer teeth rows (2 – 4 versus 3 – 6) than M. incola. Mylochromis mesembrinos has a shorter lower jaw length (24 – 34 % versus 30 – 38 % HL), more dorsal spines (16 – 18 versus 15 – 16), more lateral line scales (31 – 34 versus 26 – 32) and more anal rays (8 – 9 versus 7 – 9) than M. lateristriga. Mylochromis mesembrinos has a shorter lower jaw length (24 – 34 % versus 35 – 38

% HL) than M. melanotaenia. Mylochromis mesembrinos has fewer teeth rows on upper jaw (2 –

4 versus 6) than M. mola. Mylochromis mesembrinos has more lateral line scales (31 – 34 versus

30) than M. sphaerodon. Mylochromis mesembrinos has more lateral line scales (31 – 34 versus

26 – 30) than M. subocularis. Mylochromis mesembrinos has fewer lateral line scales (31 – 34 versus 33 – 35) and more teeth rows (3 – 7 versus 3) than M. notos. Mylochromis mesembrinos has more anal rays than M. strombodaptes (10 – 11 versus 7 – 9). Mylochromis mesembrinos has more anal rays (10 – 11 versus 7 – 8) than M. boadzului. Mylochromis mesembrinos has a longer post orbital head length (39 – 42 % versus 26 – 31 % HL) and a longer preorbital length (26 – 37

152

% versus 22 – 25 % HL) than M. lithoschalis. Mylochromis mesembrinos has fewer gill rakers on the first ceratobranchial (8 – 12 versus 12 – 14) and fewer teeth rows on the upper jaw (2 – 4 versus 4 – 6) than M. lupingui. Mylochromis mesembrinos has a shorter lower jaw length (26 –

35 % versus 31 – 38 % HL) and a shorter vertical eye diameter (25 – 36 % versus 31 – 40 % HL) than M. rhabdos. Mylochromis mesembrinos has fewer pectoral rays than M. lapararhabdos (13

– 14 versus 14 – 15).

Description

Morphometric and meristic data in Table 20. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 16 – 18 spines (mode 17) and 10 - 11 dorsal rays (mode 11). Anal fin with 3 spines and 8 – 9 anal rays (mode 8). Lateral lines scales 31 – 34 (mode 33) with 0 - 1 pored scales (1). Gill rakers on first ceratobranchial 8 – 12 (mode 9) and on first epibranchial 3 –

4 (mode 3).

Broad diagonal stripe from above operculum to caudal peduncle. White lappets with orange tips. Anal fin whitish with a dusky margin and several egg dummies (yellow with white halos).

Dusky margin on caudal Faint yellow spots on membranes of dorsal fin, more distinct posteriorly. More distinct yellow-gold spots on membranes of caudal fin. Body ground color white/silvery with gold blue metallic highlights dorsal to oblique stripe and with blue green metallic sheen on infraorbital/preorbital region. White belly, chest, gular and chin. Pelvics clear with a slightly dusky submarginal region.

153

Discussion

Although there was an overlap between the character states of M. mesembrinos and M. balteatus, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 50).

0.10 M. mesembrinos M. balteatus

) 0.05

c i

r 0.00

o h

p -0.05

(

C -0.10

D R

H -0.15 S

-0.20 -2 -1 0 1 2 PCA1 (mersistic data)

Figure 50. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. balteatus.

Although there was an overlap between the character states of M. mesembrinos and M. incola, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were

154 heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 51).

M. mesembrinos

0.10 M. incola

) a

t 0.05

r t

e 0.00

h p

r -0.05

(

C -0.10

R H

S -0.15

-0.20 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 PCA1 (meristic data)

Figure 51. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. incola.

Although there was an overlap between the character states of M. mesembrinos and M. lateristriga, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 52).

155

0.15 M. mesembrinos

M. lateristriga )

a 0.10

i r

t 0.05

h p

r 0.00

(

C -0.05

R H

S -0.10

-0.15 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 PCA1 (meristic data)

Figure 52. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. lateristriga.

There was also an overlap between the character states of M. mesembrinos and M. notos. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data showed that the two populations could be distinguished (Figure 53). An ANOVA of the principal components scores showed that the two species were significantly different along the SHRD_PC2 (p < 0.01) and the PCA1 axis (p <

0.05) independent of each other (Table 12).

156

M. mesembrinos

0.10 M. notos

)

a d

0.05

h p

r 0.00

(

P _

D -0.05

H S

-0.10 -3 -2 -1 0 1 PCA1 (meristic data)

Figure 53. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. notos.

157

Table 19. Analysis of variance for the PCA scores, which formed the minimum polygon clusters for the morphometric (SHRD_PC2) and meristic (PCA1) data for M. mesembrinos and M. notos.

Source DF Sum of Mean F Value P > F

SPCA2 Squares Square

Model 1 0.0208 0.208 15.84 0.0007

Error 21 0.276 0.0013

Corrected 22 0.0482

Total

Source

PCA1

Model 1 3.822 3.822 4.42 0.048

Error 21 18.178 0.866

Corrected 22 21.999

Total

158

Although there was an overlap between the character states of M. mesembrinos and M. lupingui, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 54).

M. mesembrinos

0.3 M. lupungui

)

a d

0.2

o h

p 0.1

(

C P

_ 0.0

H S

-0.1

-1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 PCA1 (meristic data)

Figure 54. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. lupingui.

159

Although there was an overlap between the character states of M. mesembrinos and M. rhabdos, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 55).

0.25 M. mesembrinos M. rhabdos 0.20

0.15

0.10

C P

_ 0.05

R H S 0.00

-0.05

-0.10

-0.15 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 Factor1

Figure 55. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. rhabdos.

160

Although there was an overlap between the character states of M. mesembrinos and M. lapararhabdos, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 56).

0.1 M. mesembrinos

M. lapararhabdod

)

a t

a 0.0

e m

o -0.1

(

C -0.2

H S -0.3

-1 0 1 2 3 PCA1 (meristic data)

Figure 56. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. mesembrinos and M. lapararhabdos.

161

Table 20. Morphometric and meristic values of Mylochromis mesembrinos (n = 17)

Holotype Mean Range

Standard length, mm 140.5 116.5 68.3 – 142.4

Head length, mm 44.7 37.3 21.2 – 46.6

Percent standard length

Head length 32 31.9 31 – 33

Snout to dorsal-fin origin 38 37.7 37 – 39

Snout to pelvic-fin origin 39 38.5 36 – 42

Dorsal-fin base length 56 56.1 53 – 59

Anterior dorsal to anterior anal 51 51.2 46 – 54

Anterior dorsal to posterior anal 61 61.1 57 – 64

Posterior dorsal to anterior anal 32 32.2 28 – 34

Posterior dorsal to posterior anal 16 15.6 12 – 17

Posterior dorsal to ventral caudal 19 18.9 18 – 21

Posterior anal to dorsal caudal 20 20.9 19 – 23

Anterior dorsal to pelvic-fin origin 40 38.4 32 – 42

Posterior dorsal to pelvic-fin origin 55 54.2 53 – 55

162

Caudal-peduncle length 19 18.5 16 - 21

Least caudal-peduncle depth 11 11.4 11 – 12

Body depth 37 36.1 30 – 41

Percent head length

Snout length 40 38.2 30 – 45

Postorbital head length 42 40.9 39 – 42

Horizontal eye diameter 27 30.9 27 – 38

Vertical eye diameter 25 29.9 25 – 36

Preorbital length 34 33.0 26 – 37

Cheek depth 21 21.8 16 – 25

Lower-jaw length 31 30.8 24 – 34

Head depth 75 74.9 62 - 88

Counts Mode Range

Dorsal-fin spines 16 17 16 – 18

Dorsal-fin rays 11 11 10 – 11

Anal-fin spines 3 3 3

Anal-fin rays 9 8 8 - 9

163

Pectoral-fin rays 14 14 13 - 14

Pelvic-fin rays 5 5 5

Lateral-line scales 33 33 31 - 34

Pored scales posterior of lateral line 0 1 0 - 1

Scale rows on cheek 3 3 2 - 4

Gill rakers on first ceratobranchial 8 9 8 – 12

Gill rakers on first epibranchial 3 3 3 – 4

Teeth in outer row of left lower jaw 12 12 7 - 17

Teeth rows on upper jaw 3 3 2 - 4

Teeth rows on lower jaw 3 3 3 - 7

164

6. Mylochromis notos, new species

Figure 57. Holotype of Mylochromis notos.

Etymology

From the Greek, „notos‟ means south, which indicates it is from southern Lake Malaŵi.

Material examined

Holotype. PSU 6002; 1; 139.1 mm SL; South East arm of Lake Malaŵi; Stauffer, 17th

December 1995.

Paratypes. PSU 6003; 5; 127.1 – 137.1 mm SL; data as for holotype.

Diagnosis

Mylochromis notos along with Mylochromis balteatus, Mylochromis incola, Mylochromis lateristriga, Mylochromis melanotaenia, Mylochromis mola, Mylochromis sphaerodon,

Mylochromis subocularis, Mylochromis boadzului (new species), Mylochromis lapararhabdos

(new species), Mylochromis lithoschalis (new species), Mylochromis lupingui (new species),

Mylochromis mesembrinos (new species), Mylochromis notos (new species), Mylochromis

165 rhabdos (new species) and Mylochromis strombodaptes (new species) have a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than 45 % HL.

Mylochromis notos has less teeth rows on the lower jaw (3 versus 4), more anal rays (9 –

10 versus 8) and more lateral line scales (33 – 35 versus 31 – 32) than Mylochromis balteatus.

Mylochromis notos has more lateral line scales (33 – 35 versus 26 – 32) than M. lateristriga.

Mylochromis notos has fewer cheek scales (3 versus 4), more dorsal rays (11 versus 9 – 10) and fewer teeth rows on the lower jaw (3 versus 4 - 5) than M. melanotaenia. Mylochromis notos has fewer teeth rows on lower jaw (2 – 3 versus 6), fewer teeth rows on upper jaw (3 versus 6) and more lateral line scales (33 – 35 versus 30 – 32) than M. mola. Mylochromis notos has fewer teeth rows on the lower jaw (3 versus 5) and more lateral line scales (33 – 35 versus 30) than M. sphaerodon. Mylochromis notos has more anal rays (9 – 10 versus 7 – 8), more dorsal rays (11 versus 8 – 10) and more lateral line scales (33 – 35 versus 26 – 30) than M. subocularis.

Mylochromis notos has more lateral line scales than M. strombodaptes (new species) (33 – 35 versus 28 – 32). Mylochromis notos has more dorsal rays (11 versus 8 – 10) and more anal rays

(9 – 10 versus 7 – 8) than M. boadzului (new species). Mylochromis notos has longer snout length (40 – 46 % versus 25 – 33 % HL) and a longer preorbital length (29 – 35 % versus 22 –

25 % HL) than M. lithoschalis (new species). Mylochromis notos has a deeper cheek depth (20 –

24 % versus 13 – 18 % HL), fewer gill rakers on the first ceratobranchial (8 – 9 versus 12 – 14), more lateral line scales (33 – 35 versus 30 – 31) and more anal rays (9 – 10 versus 8) than M. lupingui (new species). Mylochromis notos has a longer snout length (40 – 46 % versus 26 – 39

% HL), more dorsal rays (11 versus 9 – 10), more lateral line scales (33 – 35 versus 28 – 32) and fewer cheek scales (3 versus 4) than M. rhabdos (new species). Mylochromis notos has a shorter head length (32 – 34 % versus 37 – 40 % SL), fewer gill rakers on the first ceratobranchial (8 – 9

166 versus 11), more lateral line scales (33 – 35 versus 30) and fewer teeth rows on the upper jaw (2

– 3 versus 4) than M. lapararhabdos (new species). Mylochromis notos has a shorter snout to pelvic fin length than Mylochromis incola (37 – 42 % versus 42 – 47 % HL), more dorsal rays

(11 versus 10 – 11), more dorsal spines (16 – 17 versus 15 – 16) and more anal rays (9 – 10 versus 8 – 9) than M. incola. Mylochromis notos has fewer lateral line scales (33 – 35 versus 31

– 34) and fewer teeth rows (3 versus 3 – 7) than M. mesembrinos.

Description

Morphometric and meristic data see Table 22. Solid diagonal stripe along the side of the body. Dorsal body profile downward to caudal peduncle; ventral body profile convex. dorsal head profile convex. Dorsal fin with 16 – 17spines (mode 17) and 11 dorsal rays. Anal fin with 3 spines and 9 - 10 anal rays (mode 9). Lateral lines scales 33 – 35 (mode 34) with 0 – 2 pored scales (mode 0). Gill rakers on first ceratobranchial 8 – 9 (mode 9) and on first epibranchial 3 – 4

(mode 4).

Broad diagonal stripe from above operculum to caudal peduncle. White lappets with orange tips. Anal fin whitish with a dusky margin and several egg dummies (yellow with white halos).

167

Discussion

Although there was an overlap between the character states of M. notos and M. incola, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 58).

0.10 M. notos

M. incola

) a

t 0.05

t e

m 0.00

m (

-0.05

_ D

R -0.10

H S

-0.15 -1.5 -1.0 -0.5 0.0 0.5 1.0 PCA1 (meristic data)

Figure 58. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. notos and M. incola.

168

There was also an overlap between the character states of M. notos and M. mesembrinos. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data showed that the two populations could be distinguished (Figure 59). An ANOVA of the principal components scores showed that the two species were significantly different along the SHRD_PC2 (p < 0.01) and the PCA1 axis (p <

0.05) independent of each other (Table 21).

Figure 59. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. notos and M. mesembrinos.

169

Table 21. Analysis of variance for the PCA scores, which formed the minimum polygon clusters for the morphometric (SHRD_PC2) and meristic (PCA1) data for M. mesembrinos and M. notos.

Source DF Sum of Mean F Value P > F

SPCA2 Squares Square

Model 1 0.096 0.096 54.29 <0.0001

Error 23 0.041 0.002

Corrected 24 0.137

Total

Source

PCA1

Model 1 4.019 4.019 4.63 0.0422

Error 23 19.981 0.869

Corrected 24 24.000

Total

170

Table 22. Morphometric and meristic values of Mylochromis notos (n = 6)

Holotype Mean Range

Standard length, mm 139.1 134.81 127.1 - 139.1

Head length, mm 46.4 44.0 40.9 - 46.4

Percent standard length

Head length 33 32.7 32 – 34

Snout to dorsal-fin origin 40 37.8 36 – 40

Snout to pelvic-fin origin 40 39.7 37 – 42

Dorsal-fin base length 56 56.0 55 – 57

Anterior dorsal to anterior anal 50 50.0 49 – 51

Anterior dorsal to posterior anal 60 60.2 59 – 61

Posterior dorsal to anterior anal 32 32.2 31 – 33

Posterior dorsal to posterior anal 16 15.3 15 – 16

Posterior dorsal to ventral caudal 20 18.8 17 – 20

Posterior anal to dorsal caudal 22 21.7 20 – 23

Anterior dorsal to pelvic-fin origin 39 38.7 38 – 39

Posterior dorsal to pelvic-fin origin 53 53.2 53 – 54

171

Caudal-peduncle length 18 19.2 18 – 20

Least caudal-peduncle depth 12 11.8 11 - 12

Body depth 39 36.8 35 - 39

Percent head length

Snout length 46 42.8 40 – 46

Postorbital head length 38 39.0 38 – 41

Horizontal eye diameter 30 29.8 27 – 33

Vertical eye diameter 29 29.0 25 – 33

Preorbital length 29 31.7 29 – 35

Cheek depth 24 21.5 20 – 24

Lower-jaw length 35 32.7 28 – 37

Head depth 81 76.8 71 - 81

Counts Mode Range

Dorsal-fin spines 17 17 16 – 17

Dorsal-fin rays 11 11 11

Anal-fin spines 3 3 3

Anal-fin rays 10 9 9 – 10

172

Pectoral-fin rays 13 13 13 - 14

Pelvic-fin rays 5 5 5

Lateral-line scales 33 34 33 – 35

Pored scales posterior of lateral line 0 0 0 – 2

Scale rows on cheek 3 3 3

Gill rakers on first ceratobranchial 9 9 8 – 9

Gill rakers on first epibranchial 4 4 3 – 4

Teeth in outer row of left lower jaw 10 10 10 – 13

Teeth rows on upper jaw 3 3 3

Teeth rows on lower jaw 3 3 3

173

7. Mylochromis rhabdos, new species

Figure 60. Holotype of Mylochromis rhabdos.

Etymology

From the Greek, „rhabdos‟ means stripe, which indicates the diagonal stripe on the side of the body.

Material examined

Holotype. PSU 6014; 1; 98.2 mm SL; Nkhata Bay, Lake Malaŵi, 10 04.45S 34

32.37E; Konings, January, 2010.

Holotype. PSU 6014; 9; 57.5 – 93.5 mm SL; data as for holotype.

174

Diagnosis

Mylochromis rhabdos along with Mylochromis balteatus, Mylochromis incola, Mylochromis lateristriga, Mylochromis melanotaenia, Mylochromis mola, Mylochromis sphaerodon,

Mylochromis subocularis, Mylochromis boadzului (new species), Mylochromis lapararhabdos

(new species), Mylochromis lithoschalis (new species), Mylochromis lupingui (new species),

Mylochromis rhabdos has a shallower cheek depth (14 – 21 % versus 22 – 29 % HL), a shorter caudal peduncle length (14 – 18 % versus 19 % SL), a shorter preorbital length (21 – 26

% versus 29 – 35 % HL) and more dorsal spines (17 – 18 versus 15 – 16) than M. balteatus.

Mylochromis rhabdos has a shorter preorbital length (21 – 26 % versus 30 – 33 % HL), a longer dorsal-fin base length (54 – 59 % versus 48 – 52 % SL), a longer anterior dorsal to posterior anal length (58 – 61 % versus 54 – 56 % SL) and more dorsal spines (17 – 18 versus 15 – 16) than M. incola. Mylochromis rhabdos has more dorsal spines (17 – 18 versus 15 – 16) than M. lateristriga. Mylochromis rhabdos has a shallower cheek depth (14 – 21 % versus 23 – 27 %

HL), a shorter post dorsal to ventral caudal length (16 – 19 % versus 20 % SL), a shorter caudal peduncle length (14 – 18 % versus 19 – 20 % SL), and more dorsal spines (17 – 18 versus 15 –

16) than M. melanotaenia. Mylochromis rhabdos has fewer teeth rows on upper jaw (3 – 4 versus

6), fewer teeth rows on lower jaw (2 – 4 versus 6), and more dorsal spines (17 – 18 versus 16) than M. mola. Mylochromis rhabdos has a shorter preorbital length (21 – 26 % versus 31 – 32 %

175

HL), more cheek scales (4 versus 2 – 3), fewer teeth rows on lower jaw (2 – 4 versus 5), and more dorsal spines (17 – 18 versus 15 - 16) than M. sphaerodon. Mylochromis rhabdos has more dorsal spines (17 – 18 versus 14 – 16) and more cheek scales (4 versus 3 – 4) than M. subocularis. M. rhabdos has a shorter snout length (26 – 39 % versus 40 – 46 % HL), fewer dorsal rays (9 – 10 versus 11), fewer lateral line scales (28 – 32 versus 33 – 35) and more cheek scales (4 versus 3) than M. notos. Mylochromis rhabdos has a longer lower jaw length (31 – 38

% versus 26 – 35 %) and a longer vertical eye diameter (31 – 40 % versus 25 – 36 % HL) than

M. mesembrinos. Mylochromis rhabidos has a shorter caudal peduncle length (14 – 18 % versus

17 – 21 %), more dorsal spines (17 – 18 versus 15 – 17) and fewer dorsal rays (9 – 10 versus 10

– 11) than M. strombodaptes. Mylochromis rhabdos has a longer lower jaw length (31 – 38 % versus 26 – 31 % HL) and more gill rakers on the first ceratobranchial (9 – 11 versus 8 – 9) than

M. boadzului. Mylochromis rhabdos has a longer jaw length (31 – 38 versus 23 – 32 % versus %

HL), a longer post orbital head length (30 – 35 % versus 26 – 31 % HL) and more gill rakers on the first epibranchial (9 – 11 versus 8 – 9) than M. lithoschalis. Mylochromis rhabdos has a shorter preorbital length (21 – 26 % versus 31 – 34 % HL), a shorter snout length (26 – 39 % versus 42 – 44 % HL) and fewer gill rakers on the first ceratobranchial (9 – 11 versus 12 – 14) than M. lupingui. Mylochromis rhabdos has a shorter preorbital length (21 – 26 % versus 30 – 32

% HL), a bigger horizontal eye diameter (33 – 41 % versus 22 – 27 % HL), a shorter snout length (26 – 39 versus 43 – 45 % HL) and fewer dorsal fin rays (9 – 10 versus 11) than M. lapararhabdos.

Description

Morphometric and meristic data in Table 23. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head

176 profile convex. Dorsal fin with 17 – 18 spines (mode 17) and 9 – 10 dorsal rays (mode 10). Anal fin with 3 spines and 8 - 9 anal rays (mode 8). Lateral lines scales 28 – 32 (mode 30) with 0 - 1 pored scales (mode 0). Gill rakers on first ceratobranchial 9 – 11 (mode 10) and on first epibranchial 3 – 4 (mode 4).

Discussion

Although there was an overlap between the character states of M. rhabdos and M. mesembrinos, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supports the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 61).

0.25 M. rhabdos M. mesembrinos

0.20

)

t a

d 0.15

r t

e 0.10

o h

p 0.05

m (

0.00

P _

D -0.05

R H S -0.10

-0.15 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 PCA1 (meristic data)

Figure 61. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. rhabdos and M. mesembrinos.

177

Although there was an overlap between the character states of M. rhabdos and M. strombodaptes, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 62).

0.20 M. rhabdos M. strombodaptes

) 0.15

i 0.10

m o

h 0.05

m (

0.00

_ D

R -0.05

H S

-0.10

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 PCA1 (meristic data)

Figure 62. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. rhabdos and M. strombodaptes.

Although there was an overlap between the character states of M. rhabdos and M. boadzului, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species are heterospecific. The

178 minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 63).

0.2 M. rhabdos

M. boadzului

)

t a

d 0.1

o h

p 0.0

(

P _

D -0.1

H S

-0.2 -1.5 -1.0 -0.5 0.0 0.5 1.0 PCA1 (meristic data)

Figure 63. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. rhabdos and M. boadzului.

Although there was an overlap between the character states of M. rhabdos and M. lithoschalis, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 64).

179

0.2 M. rhabdos

M. lithoschalis

)

a d

0.1

h p

r 0.0

(

P _

D -0.1

H S

-0.2 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 PCA1 (meristic data)

Figure 64. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. rhabdos and M. lithoschalis.

180

Table 23. Morphometric and meristic values of Mylochromis rhabdos (n = 10)

Holotype Mean Range

Standard length, mm 98.2 79.9 57.5 – 98.2

Head length, mm 34.1 27.4 19.3 – 34.1

Percent standard length

Head length 35 34.4 33 – 35

Snout to dorsal-fin origin 38 38.3 36 – 40

Snout to pelvic-fin origin 40 40.1 37 – 42

Dorsal-fin base length 57 56.1 54 – 59

Anterior dorsal to anterior anal 49 48.1 46 – 50

Anterior dorsal to posterior anal 60 59.3 58 – 61

Posterior dorsal to anterior anal 29 28.2 27 – 30

Posterior dorsal to posterior anal 14 13.4 13 – 14

Posterior dorsal to ventral caudal 18 17.3 16 – 19

Posterior anal to dorsal caudal 19 18.2 16 - 19

Anterior dorsal to pelvic-fin origin 35 33.3 30 - 35

Posterior dorsal to pelvic-fin origin 53 52.1 51 – 53

181

Caudal-peduncle length 16 15.7 14 – 18

Least caudal-peduncle depth 12 11.3 10 – 12

Body depth 34 32.2 30 - 34

Percent head length

Snout length 39 34.5 26 – 39

Postorbital head length 33 32.6 30 – 35

Horizontal eye diameter 33 37.3 33 – 41

Vertical eye diameter 31 36.3 31 – 40

Preorbital length 25 24.0 21 – 26

Cheek depth 21 17.2 14 – 21

Lower-jaw length 33 34.6 31 – 38

Head depth 60 61.6 57 - 67

Counts Mode Range

Dorsal-fin spines 17 17 17 – 18

Dorsal-fin rays 10 10 9 – 10

Anal-fin spines 3 3 3

Anal-fin rays 9 8 8 – 9

182

Pectoral-fin rays 13 14 13 - 14

Pelvic-fin rays 5 5 5

Lateral-line scales 29 30 28 – 32

Pored scales posterior of lateral line 0 0 0 – 1

Scale rows on cheek 4 4 4

Gill rakers on first ceratobranchial 11 10 9 – 11

Gill rakers on first epibranchial 4 4 3 – 4

Teeth in outer row of left lower jaw 11 12 10 – 12

Teeth rows on upper jaw 3 3 3 – 4

Teeth rows on lower jaw 3 3 2 - 4

183

8. Mylochromis strombodaptes, new species

Figure 65. Holotype of Mylochromis strombodaptes.

Etymology

From the Greek, „strombodaptes‟ means snail eater, which indicates it eats snails.

Material examined

Holotype. PSU 6006; 1; 109.6 mm SL; Thumbi East Island, Lake Malaŵi; Stauffer, 2nd

August 2004.

Paratypes. PSU 6007; 19; 56.9 – 122.7 mm SL; Thumbi East Island, Lake Malaŵi; Stauffer,

2nd August 2004.

184

Diagnosis

Mylochromis strombodaptes along with Mylochromis balteatus, Mylochromis incola,

(new species), Mylochromis mesembrinos (new species), Mylochromis notos (new species),

Mylochromis rhabdos (new species) and Mylochromis strombodaptes (new species) have a snout to dorsal fin origin length greater than 35 % SL, a preorbital head length of less than 45 % HL.

Mylochromis strombodaptes has a shorter lower jaw length (26 – 35 % versus 31 – 40 % HL) and fewer teeth rows on the upper jaw (2 – 4 versus 3 – 5) than M. balteatus. Mylochromis strombodaptes has a shorter snout length (30 – 39 % versus 39 – 46 % HL), a longer post dorsal to post anal length (14 - 16 % versus 12 – 14 % SL) and fewer teeth rows on the upper jaw (2 – 4 versus 3 – 6) than M. incola. Mylochromis strombodaptes has a longer post dorsal to post anal length (14 – 16 versus 11 – 15 % SL) and fewer teeth rows (2 – 4 versus 3 – 6) than M. lateristriga. Mylochromis strombodaptes has a shorter lower jaw length (26 – 35 % versus 35 –

38 % HL) and fewer teeth rows on upper jaw (2 – 4 versus 4 – 6) than M. melanotaenia.

Mylochromis strombodaptes has fewer teeth rows in lower jaw (2 – 4 versus 6) and fewer teeth rows in lower jaw (2 – 5 versus 6) than M. mola. Mylochromis strombodaptes has fewer teeth rows on the upper jaw (2 -4 versus 4 – 6) and fewer teeth rows on the lower jaw (2 – 5 versus 5) than M. sphaerodon. Mylochromis strombodaptes has more dorsal rays (10 – 11 versus 8 – 10) and more pectoral rays (12 – 15 versus 10 – 13) than M. subocularis. Mylochromis

185 strombodaptes has fewer lateral line scales than M. notos (new species) (28 – 32 versus 33 – 35).

Mylochromis strombodaptes has fewer anal rays than M. mesembrinos (7 – 9 versus 10 – 11).

Mylochromis strombodaptes has a shorter least caudal peduncle length (10 – 12 % versus 12 – 13

% SL), more dorsal rays (10 – 11 versus 8 – 10) and more lateral line scales (31 – 33 versus 28 -

32) than M. boadzului. Mylochromis strombodaptes has a longer postorbital head length than (34

– 42 % versus (26 – 31 % HL) than M. lithoschalis. Mylochromis strombodaptes has a shorter snout length (30 – 39 % versus 42 – 44 % HL) and fewer gill rakers on the first ceratobranchial

(9 – 11 versus 12 – 14) than M. lupingui. Mylochromis strombodaptes has a longer caudal peduncle length (17 – 21 % versus 14 – 18 % SL), fewer dorsal spines (15 – 17 versus 17 – 18) and more dorsal rays (10 – 11 versus 9 – 10) than M. rhabdos. Mylochromis strombodaptes has a shorter snout length (30 – 39% versus 43 – 45 % HL) than M. lapararhabdos.

Description

Morphometric and meristic data in Table 25. Solid diagonal stripe along the side of the body.

Dorsal body profile downward to caudal peduncle; ventral body profile convex. Dorsal head profile convex. Dorsal fin with 15 - 17 spines (mode 16) and 10 – 11 (mode 11) dorsal rays. Anal fin with 3 spines and 7 – 9 anal rays (mode 8). Lateral lines scales 29 - 32 with 0 - 2 pored scales

(mode 0). Gill rakers on first ceratobranchial 9 – 10 (mode 9) and on first epibranchial 3 – 4

(mode 4).

Color description not available for live specimen.

Discussion

Although there was an overlap between the character states of M. strombodaptes and M. balteatus, analysis of the sheared principal components of the morphometric data the principal

186 components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 66).

0.10 M. strombodaptes

M. balteatus

)

a t

a 0.05

e m

o 0.00

(

C -0.05

H S -0.10

-2 -1 0 1 2 PCA1 (meristic data)

Figure 66. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. balteatus.

Although there was an overlap between the character states of M. strombodaptes and M. incola, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 67).

187

0.10 M. strombodaptes

M. incola

) a

t 0.05

r t

e 0.00

o m

( -0.05

_ D

R -0.10

H S

-0.15 -2 -1 0 1 2 3 PCA1 (meristic data)

Figure 67. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. incola.

There was also an overlap between the character states of M. strombodaptes and M. lateristriga. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data showed that the two populations could be distinguished (Figure 68). An ANOVA of the principal components scores showed that the two species were significantly different along the SHRD_PC2 (p < 0.001) and the PCA1 axis (p < 0.001) independent of each other (Table 24).

188

M. strombodaptes

0.10 M. lateristriga

)

a t

a 0.05

t e

m 0.00

M (

-0.05

D R

H -0.10 S

-0.15 -2 -1 0 1 2 3 PCA1 (meristic data)

Figure 68. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. lateristriga.

189

Table 24. Analysis of variance for the PCA scores, which formed the minimum polygon clusters for the morphometric (SHRD_PC2) and meristic (PCA1) data for M. strombodaptes and M. lateristriga.

Source DF Sum of Mean F Value P > F

SPCA2 Squares Square

Model 1 0.095 0.095 72.85 <0.0001

Error 34 0.045 0.001

Corrected 35 0.140

Total

Source

PCA1

Model 1 16.046 16.046 28.78 <0.0001

Error 34 18.954 0.557

Corrected 35 35.000

Total

Although there was an overlap between the character states of M. strombodaptes and M. melanotaenia, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were

190 heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 69).

0.15 M. strombodaptes

M. melanotaenia

)

a t

a 0.10

t e

m 0.05

m (

0.00

_ D

R -0.05

H S

-0.10 -2 -1 0 1 2 3 PCA1 (meristic data)

Figure 69. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. melanotaenia.

Although there was an overlap between the character states of M. strombodaptes and M. sphaerodon, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 70).

191

0.10 M. strombodaptes

M. sphaerodon )

a 0.05

r t

e 0.00

p r

o -0.05

(

C P

_ -0.10

H S

-0.15

-2 -1 0 1 2 PCA1 (meristic data)

Figure 70. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. sphaerodon.

Although there was an overlap between the character states of M. strombodaptes and M. subocularis, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 71).

192

0.2 M. strombodaptes

M.subocularis

)

a d

0.1

h p

r 0.0

(

P _

D -0.1

H S

-0.2 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 PCA1 (meristic data)

Figure 71. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. subocularis.

Although there was an overlap between the character states of M. strombodaptes and M. boadzului, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 72).

193

0.10 M. strombodaptes

M. boadzului

) a

t 0.05

r t

e 0.00

r o

m -0.05

(

_ D

R -0.10

H S

-0.15 -2 -1 0 1 2 PCA1 (meristic data)

Figure 72. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. boadzului.

Although there was an overlap between the character states of M. strombodaptes and M. rhabdos, analysis of the sheared principal components of the morphometric data the principal components of the meristic data, supported the contention that these two species were heterospecific. The minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap (Figure 73).

194

0.20 M. strombodaptes M. rhabdos

) 0.15

i 0.10

m o

h 0.05

m (

0.00

_ D

R -0.05

H S

-0.10

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 PCA1 (meristic data)

Figure 73. Plot of sheared second principal components of morphometric data and first principal components of meristic data for M. strombodaptes and M. rhabdos.

195

Table 25. Morphometric and meristic values of Mylochromis strombodaptes (n = 20)

Holotype Mean Range

Standard length, mm 109.6 77.9 56.9 – 122.7

Head length, mm 37.7 26.3 19.1 – 41.9

Percent standard length

Head length 34 33.8 32 - 35

Snout to dorsal-fin origin 39 39.2 38 – 42

Snout to pelvic-fin origin 40 39.6 38 – 42

Dorsal-fin base length 57 54.2 51 – 57

Anterior dorsal to anterior anal 50 48.0 46 – 51

Anterior dorsal to posterior anal 61 58.5 57 – 61

Posterior dorsal to anterior anal 31 29.9 28 – 32

Posterior dorsal to posterior anal 16 14.6 14 - 16

Posterior dorsal to ventral caudal 20 18.6 17 – 21

Posterior anal to dorsal caudal 21 20.0 16 – 23

Anterior dorsal to pelvic-fin origin 39 36.4 34 – 39

Posterior dorsal to pelvic-fin origin 53 52.0 50 – 53

196

Caudal-peduncle length 19 18.7 17 – 21

Least caudal-peduncle depth 11 11.2 10 - 12

Body depth 35 34.5 33 – 37

Percent head length

Snout length 38 33.9 30 – 39

Postorbital head length 40 37.6 34 – 42

Horizontal eye diameter 28 34.2 28 – 41

Vertical eye diameter 28 34.6 28 – 41

Preorbital length 21 28.8 23 – 36

Cheek depth 23 19.6 15 – 23

Lower-jaw length 31 30.0 26 – 35

Head depth 66 64.4 57 - 73

Counts Mode Range

Dorsal-fin spines 15 16 15 – 17

Dorsal-fin rays 11 11 10 – 11

Anal-fin spines 3 3 3

Anal-fin rays 8 8 7 – 9

197

Pectoral-fin rays 13 5 12 - 15

Pelvic-fin rays 5 14 5

Lateral-line scales 31 31 28 – 32

Pored scales posterior of lateral line 1 0 0 – 2

Scale rows on cheek 4 2 1 – 4

Gill rakers on first ceratobranchial 9 9 9 – 11

Gill rakers on first epibranchial 4 4 3 – 4

Teeth in outer row of left lower jaw 13 13 6 – 15

Teeth rows on upper jaw 2 3 2 – 4

Teeth rows on lower jaw 4 4 2 – 5

198

General discussion on systematic of the genus Mylochromis

Using the sheared principal components analysis resulted in the description of eight new species of the genus Mylochromis. Although, there were overlaps between the character states of some species, in most cases, analysis of the sheared principal components of the morphometric data and the principal components of the meristic data supported the contention that the species were heterospecific. This was because minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data did not overlap. Where there was an overlap between the character states of any two species, the minimum polygon clusters of the sheared second principal components of morphometric data and first principal components of meristic data was inspected to see if the two populations could be distinguished. An ANOVA of the principal components scores was carried out to determine if the any two species whose minimum polygon clusters overlap were significantly different along the SHRD_PC2 and the PCA1 axis independent of each other.

The new species described here are valid species based on the evolutionary species concept. Since the evolutionary species concept is non-operational, the morphological species concept was used as a surrogate species in delimiting these new species based on their differences in shape and meristic characters. Based on morphological and meristic differences, I believe that these new species are on independent evolutionary trajectories that are separate from other lineages I the genus Mylochromis.

Konings (2007) suggested that the members of the genus Mylochromis should be split into two genera: the genus should contain only species with a continuous diagonal stripe (Figure

199

74) because the type species M. lateristriga has a continuous diagonal stripe and another with those having a blotched and interrupted diagonal stripe (Figure 75). This study failed to find support for this split. This is because in literature, it has been indicated that some species could have members with both forms of diagonal stripe. For example, members of M. labidodon from central and southern part of Lake Malaŵi appear to have no such stripe while those from the northern part of the lake have a diagonal stripe. The diagonal stripe of M. formosus is usually continuous but sometimes is broken up into spots. In M. ericotaenia, the diagonal stripe is blotchy in adults and continuous in juveniles (Konings 2007). M. incola has a continuous diagonal band, which is sometimes partly divided into spots (Eccles and Trewavas 1989).

Figure 74. Mylochromis lapararhabdos showing a continuous diagonal stripe.

Figure 75. Mylochromis lithoschalis showing the blotchy and interrupted diagonal stripe.

200

The genus Mylochromis is an unsatisfactory grouping. While those species with a diagonal stripe, large mouth and predatory life style are placed in the genus Buccochromis and those with a diagonal stripe and laterally compressed body snout are placed in the genus

Lichnochromis, those species with a diagonal stripe and lacking specialized morphologies are placed in the genus Mylochromis. I conclude that the genus Mylochromis is probably polyphyletic. Based on my knowledge of this genus, the feeding behavior can be used to split this genus. I suggest that the snail-eating fishes should probably be put in their own genus since they have heavy molariform teeth on their pharyngeal bones. I recommend that further studies should try to look for apormorphic characters that could be used to split this genus into monophyletic groups.

201

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208

Vita

Wilson Wesley Lazaro Jere

Education

 PhD in Wildlife and Fisheries Science, Pennsylvania State University, PA, USA, 2010  MSc. in Aquaculture and Aquatic Resources Management, Asian Institute of Management, Thailand, 2002  BSc. in Agriculture with Distinction, University of Malaŵi, 1998.  Diploma in Agriculture with Credit, University of Malaŵi, 1995

Work Experience

 Lecturer in Fish Genetics and Breeding at Bunda College of Agriculture, University of Malaŵi, December 2002 to present  District Environmental Officer, Ministry of Forestry, Fisheries and Environmental Affairs, Malaŵi Government. December 1998 to December 1999.

Publications

DZIYANJANANI, J. AND W. W. L. JERE. 2005. The Effect of Water Temperature on the Sex Ratios of Oreochromis shiranus. In: Safalaoh, A. C. L.; J. P. Gowela. and A. H. Mtethiwa (Editors) Proceedings of the 2nd Bunda College Research Dissemination Conference, Lilongwe. pp 5-7. ISSN 1816-2930.

JERE, W. W. L.; BART, A.; MAIR, G. AND YI, Y. 2003. The Use of Correction of Correction Factors in the Evaluation of Growth Performance of Tilapia Genotypes. Aqua-Fish Technical Report. Aquaculture and Fisheries Science Department, Bunda College of Agriculture, Lilongwe, Malaŵi. pp 18-22. ISSN 1729-4177.

KAUNDA, E. K. W., J. L. ANDERSON, J. KANG‟OMBE AND W. W. L. JERE. 2007. Effect of clear plastic sheeting on water temperature and growth of Tilapia rendalli in earthen ponds. Aquaculture Research, 38, 1113-1116.

MSUKA, C. G., J. S. LIKONGWE, J. J. KANG‟OMBE, W. W. L. JERE AND A. H. MTETHIWA. 2009. The effects of dietary protein and water temperature on performance of T. rendalli juveniles reared in indoor tanks. Pakistan Journal of Nutrition 8: 1526 – 1531